We have crossed both the North Atlantic and the South Atlantic and, that small sample, strongly agrees with your assessment. The North Atlantic can pack a punch. Admittedly our timing for the South Atlantic crossing was more careful since it was a long 3650 nautical miles so they aren't directly comparable but the northern one was definitely more challenging from a weather perspective.
Interesting to see the fuel bladders. I've been running the numbers on taking a Ranger Tug across the Tasman Sea using a cockpit fuel bladder. Nice to see someone else using them also. You guys are a masterclass in open ocean trawling. Keep up the great work. Thanks for the content.
Thanks for the feedback. A great source for fuel bladders is ATL with a broad selection of standard sizes and they also do custom designs. Our experience is that the key to a stable bladder is fully filling it. We have had ours out in heavy weather and they never shifted. As an example of how full we aim to get it, we have a picture of me standing on one where I'm hard sinking in at all. Good luck with your project.
This is the best yacht vid I have seen. Tells what reallity is over the walk thoughts. Besides, I have owned half those yacht but always have to stop daydreaming and get back to earning the rent.
Interesting. I always just assumed if your boat couldnt hold enough fuel you couldnt go. I didnt even think about carrying extra fuel bladders! learned alot, thanks for sharing!
It's a common trick from the aircraft sector where short distance planes need to rarely need to do a larger hop. The military is another frequent user where they often need to store fuel at temporary locations. Another popular use of fuel bladders is in high speed sports fishers that need to run out a hundred miles or so to get out past the continental shelf on the US east coast. These are fuel hungry boats running at 20 and sometimes even beyond 30 kts so bladders are frequently used.
I Love the Thoughfulness and planning that goes into your videos. This has taught me quite a few helpful pointers, as I too will become a Yacht Operator.
You two have such a great aura! I love listening and learning from you both! We hope to buy a Nordhavn after I retire and go up and down E and W coasts! More videos please! I’ve watched this one at least 4 times!😳😎😎😎👊👊👊
I've had a little boating experience on friends boats and always enjoyed it---but I've never dreamed or wanted to own a boat until recently watching your Dirona videos.
Thanks for sharing! I've seen pictures of your boat and other Nordhavns, but seeing you crawl around in the engine room really helps understand the scale. Safe travels!
Boats are tight places but most places on Dirona are surprisingly easy to get to. However, as on all boats, there are a few service tasks where more space would really be welcome.
Great video to showcase how much better suited sailboats are for blue water crossings. Fuel bladders, storm covers, oh boy. Give me an equivalent length sailboat any day of the week.
It is true that more sailboats than powerboats make the trip but, having crossed every ocean in this boat, there are some upsides in comfort. In storm conditions, it's really nice to be inside a warm and dry pilot house.
@@MVDirona Oh, for sure and everybody to their own of course. You guys do an amazing job and your choice of vessel clearly works for you. Personally, I tried to love powered boats and never managed to. There's magic to the moment you switch off an engine and the wind takes over. I love how a boat just tenses and relaxes at the same time. And of course, there are very nice sailboats available with a pilot house. ;)
Absolutely brilliant video's you both do,I have a narrow boat that I travel round the inland canal system in and my favourite part of my trips are crossing tidal rivers and the Wash Boston to the Fens on a calm day of course.Thanks again and keep the video's coming.
Yes, fuel bladders are used frequently to extend the range of small aircraft. It's a nice solution and there are a lot of different applications: atlinc.com/rangeextender.html.
Most of our ocean crossings where great but we made the North Atlantic crossing at a less favorable time of the year so we saw some weather. Nothing dangerous but it was quite rough: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html
Parts of the North Atlantic crossing is in this video: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html. It's a bit rough but you can find lots of relaxing ocean crossings up at: th-cam.com/users/mvdirona.
The fuel bladders are connected to a bulkhead fitting via short fuel hoses with cam lock fittings. There is a fuel transfer pump inside the boat that is responsible for pumping fuel between tanks. From inside the boat, the fuel can be transferred from the bladders into the tanks below. More details on the process here: mvdirona.com/2012/12/fuel-for-the-crossing/.
Long range fishing on a smaller boat people will head out on a loop drop a bladder with a beacon in the ocean do your loop , refuel load the bladder and head back in
Just subscribed! I love watching nordhavns in their element, one day I hope to have a nordhavn of my own! Coming from a guy that has no experience in owning a boat, I have to say that nordhavn yachts are the best trawlers out there, and that's saying a lot... Lol love your videos, keep up the good work!
Y'all are so blessed to joy coursing across the ocean this way.... I've loved large boats as long as I can remember, but my wife of 40+ years is as scared of water as I am heights...LOL. I got her in a 14 foot fishing boat out on a small lake one time. All was go until the motor failed and the wind kicked up. I tried to paddle the boat back to shore but the wind was blowing us into the middle of the inland lake. She was freaking out. A couple of guys in a canoe towed to a near by dock and gave me a ride to get my truck and trailer. That next day the boat was sold!!! LOL... But I use to get out on out big old Lake Michigan on a friends 30 foot charter boat when ever the chance came my way... But no more physically able to do it. but at my age riding my 3 wheel motorcycle now and then is fun enough...LOL,LOL.. Her and I have ridden motorcycle for 38 years together. But she has always had to ride her own Harley which she's in love with...LOL... Oh well I've rambled on enough. Have fun, be safe, and most of all be blessed as y'all cross the ocean and your time in Ireland... May the Good LORD bring y'all into safe harbors... I'll be laying here watching for your vlog updates... BBE...
I'm not sure motorcycles are safer than long range cruisers but it's super hard to have an interesting life without accepting some risk. We're currently enjoying a nice slow run south through Scotland's Caledonian Canal: mvdirona.com
you are not a kid ,but you move around like ONE !!!!!! always believe a big boat is the best way to keep one fit !!!!! it takes TONs of calories keep a yacht in good shape !!!
I agree that, if you take care of your own boat, it does take some activity. Potentially an even more important factor is going to new places and seeing new things tends to make you more active both mentally and physically.
I sure as hell am a kid, whenever I’m on a ship, I’ll be walking around the whole thing but mostly at the bow or stern. Sound of the stern’s volume is highly increased from the engine.
I'm the same way when touring ships and, over the years, have toured some very interesting examples: *Oil Tanker: mvdirona.com/2019/09/oil-tanker-tour/ *Scalloper: mvdirona.com/2016/11/on-board-a-canadian-scalloper/ *Container Ship: mvdirona.com/2012/06/on-board-the-hanjin-oslo/ *Cruise Ship: mvdirona.com/2016/02/behind-the-scenes-on-the-westerdam-2/ *Steamship: mvdirona.com/2019/07/historic-steamship-tour/ *Nuclear Submarine: mvdirona.com/2016/05/uss-california-distinguished-visitor-embark/ *Cable Layer: perspectives.mvdirona.com/2017/01/cs-responder-trans-oceanic-cable-layer/ *Ice Breaker: mvdirona.com/2015/01/on-board-the-aurora-australis/ *Arctic Research Vessel: mvdirona.com/2015/10/on-board-the-marion-dufresne/
0:30 I see You don't have a flopper stopper on the starboard side. Is one flopper stopper on the port side as effective as when there are two, or is there a difference, and if so, is there a big difference?
There is a flopper stopper on both sides of the boat but we frequently only use one. A single flopper stopper seems to have about 70% of the anti-roll forces as using two. I suspect in the limit when it's really rough 2 floppers is 2 about twice as effective as a single flopper stopper. But, in more mild conditions, one is very effective and dome boats elect to only install one.
Really nice, everything has its place aboard your boat, electronics and electrical lay out is a electrical engineering feat! can’t understand the 41 miserable souls who put thumbs down?
Excellent video. I am impressed with your videos. they are factual and show the amount of real prep that is required for a ocean passage. thank you for sharing your journey.
I'm struck by the passion with which you pursue your dream. This is the second video of yours I've seen. The mind boggles at what effect your impressive knowledge and self-preservation skills would have if they were refocused from self-indulgence to more selfless pursuits.
I work full time as an engineer but I get paid for that so it probably doesn't qualify as selfless :-). This is my day job: th-cam.com/video/AyOAjFNPAbA/w-d-xo.html.
Of all the videos covering preparations for making a yacht sea ready yours was the most complete. The yacht turned out to be a Nordhavn a well thought out an complete package.
The crossing was one of our rougher ones and we had a couple of mechanical issues (th-cam.com/video/guEnTp2a6Sc/w-d-xo.html) but most of the time it's a nice relaxing run.
The transfer system is a fairly nice setup that avoids having the fuel tanks open to the weather or there being any risk of a spill. Nobody even has to be outside. There is a camlock connection on the bulkhead and on each bladder. A short hose connects the bladder to the bulkhead connection. Once there is space in the below decks tanks, we open the safety valve on the tank and then use the fuel transfer pump on the boat (it's use to move fuel around between tanks or to filter fuel in a given tank) to transfer the fuel from the bladder to the tank. This allows a risk from transfer and the bladder can be vacuumed down flat so it's totally empty and all fuel is filtered before it's put below decks as part of this process.
Getting small boats able to comfortably cover long distances takes a bit of work and thought but, clearly, starting out with a well designed and well thought out boat is crucial.
Thanks for the lovely video question: what method did you use to pump the fuel from the Bladders to the vessel main fuel tanks!? Thanks again and keep them coming Be safe & Safe sailing "boating"
Good question. The boat has a fuel transfer system designed to be able to move fuel between the 4 below deck fuel tanks. What we did was add another input to the fuel transfer pump manifold that connected to a fuel hose running to an exterior bulkhead at the back of the boat. There are short hoses that run between the exterior on deck fuel tanks to the bulkhead fitting. To pump out the fuel tanks, a manual safety valve needs to be opened on each tank after which, the fuel bladders can be pumped into the tanks below by going down to the engine room and decide where to pump the fuel, set the valves correctly and engage the fuel transfer pump. This has the advantages of not forcing the operator to be outside on deck, there is no risk of getting water into the fuel system, and you can evacuate the bladders fully. The ladder is particularly helpful in that fuel bladders with even tiny amounts of residual fuel are heavy and hard to pack away whereas fully emptied bladders are easy to deal with.
@@MVDirona thanks for the prompt reply, what a brilliant way. Love the risk assessment part of thinking. Great 👍🏼 job Thanks for sharing such technical specks It is really informative.
I haven't lost one yet but enough people have argued that just turning the boat around in the slip is probably faster and is definitely easier. We may just give in to low tech solutions and declare that the new standard operating procedure :-).
It's a pretty cool set up where, before leaving, a custom made hose is attached to each bladder by cam lock fittings and then connected to the aft bulkead also by cam locks. Then when it's time to transfer the fuel we just adjust the fuel manifold in the engine room to "Fuel Bladders" and do the transfer without going outside. Much more detail in this posting: mvdirona.com/2013/12/dirona-fuel-manifold/.
Fun video guys, thanks for sharing! I know you had a problem with flooding on the crossing but I'm sure James and Nordhavn will figure out the best solution you can come up with. I've enjoyed your Blog for a few years now. Doubt I will ever be able too buy a vessel like this, but it is fun to learn anyway. James attention to detail would do well in the Submarine Force, he'd fit right in. I spent 3yrs on a Submarine and I'm jealous James got to go out on the new Virginia Class Submarines. I haven't had the privilege. I'd love to see the changes made in the last 30yrs from my old Sturgeon Class Submarine.
I feel super lucky to have had the opportunity to take a trip on the USS California. I even got to crawl to the end of one of the forward torpedo tubes and sign my name on the outer door. Torpedo tubes look fairly big until you get down to the end :-)
There is a lot to be said for the Queen Mary approach. When taking on weather, size really does matter. Small boats put control in your hands, give us flexibility to go where we want to go when we want to go there but the weather is a downside risk we need to keep an eye on. We have crossed oceans many times but this one was rougher than usual: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html. I'll post the changes we made as a consequence of that trip sometime this week or next to mvdirona.com. We think these engineering changes are sufficient to make the weather we saw on our North Atlantic crossing a non-issues.
Did anyone else think that the first words out of his mouth would be, "great scott Marty!, if we don't fix the time machine we'll never get back to the future."
Thanks for a 'Reality Tube' on long distance voyaging. This is vital information for would-be boaters to come in contact with. Shipbuilder's crossing videos don't show the steps needed to fully secure windows at the cost of natural lighting and ventilation. What with the move to bigger windows at each level, I have been interested in just this detail.
You nailed it. All decisions in boat buildings are compromises. Small windows are better at sea but you mostly aren't at sea. Large windows are wonderful most of the time but aren't safe in extreme conditions. The solutions I like best are very thick windows or protection with storm plates. A broken window in storm conditions could end it all so it's worth being careful.
How about attaching a safety line to one of the bottom holes of the storm plate when attempting to install on the port side. That may save having to replace/dive for the plate in the event it slips. Once you have the top two screws in simply untie the safety line and carry on inserting the bottom screws. Just a friendly suggestion from someone who has dropped many things (mistakenly) into the drink!
It's hard to do it for many years without learning a quite a bit and I'm the sort of person that wants to know the "why?" behind everything but it's absolutely not required to enjoy the lifestyle at comfortable levels of risk.
How do you manage drawdown of the bladders? Fill the main tanks several times or wait till you can drop the entire stern bladder contents into each tank at one time? How do you transfer the fuel? How do the full bladders affect your stability?
Good question. We run until we have room below decks to bring a full bladder down. Once there is room to bring one down, we do it. The bladder pump down is super easy. There is a cam lock fitting on the bulkhead so pump down just requires plugging in the hose and, once that done, the tank can be pumped down without going outside. It's transferred by the central fuel transfer pump (same pump used for moving fuel between other fuel tanks) with the nice side effects of: 1) all fuel is filtered on the way below, 2) there is no chance of water ingress or fuel spills, and 3) don't need pumps outside etc. I've posted the fuel bladder stability data below but the short answer is it can still pass ISO Category A All Oceans when running with full bladders: mvdirona.com/2019/03/deck-fuel-and-vessel-stability/
Of course there is an chronological order of production but, with all the different topics covered, we don't really expect them to be watched in any specific order but I can see the upside of numbering them going forward. Thanks for the suggestion.
Just come across your video I subscribed because I'm thinking about getting one myself as there is only 2of us. We would like to stick around and enjoy your everyday experiences have a nice trip.
Probably true. It was an experiment because to avoid turning the boat around as we normally do. It takes some time to drop all the lines, unplug the boat, and then move all the lines to the other side. Then do it again. But, yes, doing that probably would have been easier.
Your right. There is currently a hurricane approaching Kinsale Ireland (where we made landfall after our North Atlantic crossing) and, even where we are currently are in Scotland (mvdirona.com) we have been seeing some big barometer swings.
Yeah, bladders in used frequently in military applications when deploying forces to new locations quickly. They are used to reposition short and medium range aircraft longer distances. They are in frequent use in the sports fisher fleets that need run longer distances to get to the pelagic fish. They are great tools to extend range.
PS, I was fascinated by the fuel bladders for long voyages. Really interesting as I only know about aviation applications. How do you pump into the tanks? Do you cross pump - ie run port tank low then pump starboard bladder into port tank to maintain trim?
Jjaus, we have a fairly simple fuel transfer system for the bladder fuel where we connect a cam to a permanent fitting on the bulkhead via a short hose section to a cam lock on the bladder tanks. When it is time to pump the fuel, the standard fuel transfer pump moves the fuel from the bladder, through the transfer filter (25 micron RACOR FPO-10), and then is directed into one of the main tanks. This has the advantage of allowing fuel to be pumped with nobody outside, doesn’t require the tank filler to be open to water ingress, filters all fuel as it leaves the bladders, and allows the bladders to be pumped completely dry so they are light and easy to handle. When fueling the main tanks, the fuel is brought in directly. We filter all fuel that is transferred from the main tanks to the day tank (wing engine) or the supply tank (all other engines) using the same 25 micron RACOR FPO-10) transfer filter and high capacity fuel pump. When transferring fuel we pump from the left side bladder to the left side tank and the same on the right side. This keeps the fuel on the same side so the fuel movement doesn't affect trim. The stern just rises slightly. If you are interested, there is a lot more information on the fuel management and transfer systems used on Dirona here: mvdirona.com/2013/12/dirona-fuel-manifold/
Ahh, makes sense. Will read your link tomorrow (sans red wine, it's Sat night here and almost bed time). We're planning buying a Prestige 550 fly and the CE rating is B. If we want to motor from EU to Carribean via N America, is it worth all the hassle and money or paying to transport it, then fly over? So many variables and new skills needed for trans-oceanic voyages. We are frankly too scared to motor from Australia to Europe through all the piracy zones, so have decided our adventure will begin somewhere in the Med.
Like you, we won't go anywhere near to any reported pirate activity. Never within 100s of miles. There are routes from Australia to North America that stay away from all pirate activity but it will force you to round South Africa which requires care with weather. We've done it and you can get lots of detail on the trip up at: mvdirona.com/Trips/indianocean2015/IndianOcean1.html. This links shows the Indian Ocean crossing but you can see the full trip by moving the map out to show the world and selecting the leg you wish to see in more detail. Certainly starting in the med is an easier plan and, generally, the run between Australia and North America is a lot of open ocean time.
You're right it is getting expensive to fuel a boat but we never found diesel to be one of the dominant costs. Even 5 years ago we were paying nearly $7/gal in some locations (e.g. Northern Australia) and we wish it were lower but it was never even close to our biggest cost. When operating a boat at displacement speeds, fuel burn can be kept relatively small. Lower costs would definitely help but world cruising is still practical at higher fuel costs.
We do move the fuel from the bladders down below as soon as we can. It does free up deck space but the primary reason we move the fuel down below is that is the most stable configuration for the boat. Just the below deck fuel load weighs more than 5 tons. For stability reasons, we want this weight as low in the boat as possible. So, as soon as there is space below, we pump the bladders empty, clean them up, and put them away. If you are interested in more details: mvdirona.com/2019/03/deck-fuel-and-vessel-stability/.
It's been awhile so I don't have the exact number but I suspect it will have been around $5,000. As you know, the price of fuel is much more in other parts of the world and, just filling the boat tanks without bladders in Australia cost over $7,0000. It can get pricey but it doesn't happen often. We have only filled the tanks twice this year and both times they weren't that low (over 1/3).
Great stuff. I'm glad that you guys took the time to show us how you prep your boat for long passages... I especially love the utilization of your fuel bladder for extra fuel for those far away excursion. I think that that's a great idea. Good for you guys! Furthermore, I would like to take this opportunity to state that I too would love to know, if you don't mind of course, how you transfer the fuel to your main tanks. I've visited the web site in which sells those bladders and seen that they have electrical powered fuel fill hoses and wonder if that's what you guys use?
Thanks for the comment Robert. We use a cool system where a passive hose is cam locked onto a permanently installed bulkhead fitting on one end and the fuel bladders on the other. Using the fuel manifold in the engine room, I can just pump the fuel below without going out side. There is a picture of the fuel transfer system in this article: mvdirona.com/2013/12/dirona-fuel-manifold/ I've outlined a bit more detail on the transfer process and advantages here: mvdirona.com/2017/10/preparing-dirona-for-the-north-atlantic-crossing/#comment-214735
As soon as we have 400 gallons used below, we pump the forward tank down. And then, once we use up enough to bring aft tanks below we do them as well. We basically clear the decks as soon as possible since it's bad for boat stability to have main tanks low with fuel on deck. It feels kind of weird to have full tanks, 1,000 nautical miles off shore and 7 days after leaving port.
Curious to know how much it costs to fuel stateside with the bladders. Also I thought the 52 and the 60 had enough fuel capacity to cross Atlantic? ...do you use the bladders to save fueling costs in Europe (must cost way more) or is it a necessity to have the extra for piece of mind? I ask as my wife and I are thinking of a Nordhavn 60 for our retirement..the main reason is for it's passagemaking ability as we have family all over the globe we wish to visit....your videos have been a great help. Thanks. Carl
Yes you are correct that both the 52 and the 60 can easily cross the Atlantic. Real range in ocean conditions is almost always far shorter than computed miledge but, at reasonable speed, Dirona can do 2500 nautical miles without bladders and 4000 with them. On fueling costs, it depends how much you need and the price but it carries 1750 gal without bladders and 2650 with them.
@@MVDirona wow...big difference in range. Having read a bit of you blog with the water ingress during your trip do you think it is still worth running the bladders ( think you said you struggled with access to lazerette to determine where the ingress was coming from) or do you thing the extra weight actually helped with stability in the bigger seas?
I'm pretty sure the bladders played no part in the water ingress problem but you bare right that they did block access to the locker that was leaking making it more difficult to correct the problem. The problems have all been mitigated: mvdirona.com/2017/12/alarms-at-115am-follow-up/ With those changes in place we wouldn't hesitate to use the bladders when we need additional range.
In this operating mode, the boat calculates out to continuing to meet CE Class A Ocean with the deck fuel. It actually can survive the main tanks being brought down to near empty with fuel on deck and remain CE Class A Ocean. It won't quite make it with empty tanks but, as I said, we don't run it this way. When we have 360 gallons of space below decks, we move the forward tank load below. Then once we have 600 gallons below decks, we move the aft load below. The goal is to have this fuel below decks in 7 to 10 days while weather reports remain fairly accurate. Dirona is CE Class A Ocean even when using fuel bladders. I'll post a more detailed blog on this at mvdirona.com.
Thanks for reply. Your Nordhavn is an impressive boat that's for sure. I've read your blog, and you had issues with flooding and a lot of water on the stern deck on your north Atlantic crossing. And I can hear you say in the vid that she's deep in the water after the fuel is stored, don't you think that could mess with the "self-draining" system on your stern deck and cause the flooding?
Our crossing was 17 days but there are more direct routes that are shorter. We went from Newport Rhode Island direct to Kinsale Ireland. That's 2,800 nautical miles. The downside of that routing is it's further north than the common one and we went early in the year so we could enjoy the summer in Ireland and Scotland so we saw 3 low pressure systems and some rough water on that crossing: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html.
Our longest cross ocean run was St. Helena to Barbados which was just under 26 days to cover 3689 nautical miles: mvdirona.com/2016/02/barbados-arrival/. Long enough that we needed to shut down the main engine for an oil change on the way across :-).
Yes, fuel bladders are heavily used in military applications where they want a quick base. They are used in military helicopters where they have special self healing properties that can allow them to take a shell and continue to hold fuel. They are used in race cars to allow massive collisions with less likelihood of fuel spills. They are used in recreational aircraft applications to move short range aircraft over longer distances. They are used by high horsepower sports fish boats to make long runs to deep water for pelagic fish hunting. And, of course, they are used by recreational boaters to increase range. Not super common but they can make a big difference. We have a 2,500 nautical mile range with good reserves in rough water which is sufficient to make any crossing but you need to chose routings carefully. Carrying deck fuel, we can reach 4,000 nautical miles under the same conditions. Another important limitation is vessel stability. Carrying deck fuel will reduce the stability of the boat and the amount of fuel that can be safely carried by a given boat depends upon boat design and worst conditions encountered. Here's some more data on our boat and the impact of deck fuel on stability: mvdirona.com/2019/03/deck-fuel-and-vessel-stability/.
@@MVDirona thank you for the information. I only knew about the land-based applications of bladders and also in combat helos. I'm an engineer by trade so I was indeed wondering about how bladders would raise a boat's center of gravity. I would expect you use the fuel from the bladders first, but I've just watched one of your videos where you explain your fuel system and it doesn't seem that's what you're doing. But maybe it isn't necessary, I suppose the limits you mention take into account the weight of the fuel in the internal tanks.
We effectively do what you are saying. We run the main tanks down 400 gallons, and then pump down the 360 gallons forward. Then we go until we have 650 gallons available below decks and pump the 600 gallons on the aft deck down. At that point, there is nothing left on deck (other than empty fuel bladders).
@@MVDirona thank you, nice to know I had the right intuition. Those Nordhavn yachts are really starting to interest me. It's probably going to be my retirement plan, in another 20 years or maybe even sooner.
A bit before retirement might make sense in that it takes time to know what you like, make sure you actually like boating, and then get a boat equipped and setup as you like for the kind of trips you plan. But, overall, your plan sounds like a good one.
When you were handling the storm covers for the side windows, i thought if they had a handle it would be easier. If it slips you have to get the scuba gear out.
I've considered using the suction holders used to install heavy glass plates in buildings. Having a handle would make handling those big, heavy plates much easier. I'll have to come up with something.
Your right that, in many ways, they would be better on the outside. Either inside or outside, the protect the boat from flooding but, on the outside, they protect the window as well. Presumably they are attached on the inside because they are so much easier to install there and they can provide the same last line of defense against flooding in either position.
We've been experimenting with different ways to install these port slide storm plates. Given the spot beside us in the marina was available, I think you are right that just moving over would have been easy/faster.
The boat has multiple fuel tanks and is equipped with a fuel transfer pump. It's a high speed electric pump that can move fuel from one tank to another. When the transfer pump transfers fuel it also forced it through a filter so the fuel can be "scrubbed" but pumping it from a tank and back to the same tank. I've added another connection on the fuel transfer manifold that connects to a bulkhead on deck. There are short hoses with quick connect fittings that connect between the on deck fuel tank and the bulk head. Once this is in place, you don't even need to go outside to tranfer fuel from the deck tanks to the main fuel tanks and there is no risk of open tank fittings allowing water ingress. It works fairly nicely and allows the fuel bladders to be pumped down flat removing all the fuel completely which makes them lighter and easier to store.
That's an important point A Nordhavn 52 can go anywhere in the world and cross any ocean but you don't have complete flexibility on routing. Fuel allows different routes, higher speed, or opens more options. The most important point to keep in mind is that most published range data you see is wildly optimistic. Ocean swell tends to reduce fuel economy greatly. As part of our boats original commisioning, John Deere engineers where on board and they did a two way (both directions) fuel economy test at 100 RPM increments. Using this data, our range with a 10% reserve was around 1,400 nautical miles at wide open throttle of 9.5 kts, 3,790nm at 6.5 kts, 4,500nm at 6kts, and an incredible 6,770nm at 5kts. Clearly you don't need more than 4,500 nautical mile range but ocean conditions are very different and we've learned our range is 2,500 nautical miles. This is excellent but there are times when you might want more. With deck fuel, our range is 4,000 nautical miles. The trip you were asking about was Newport Rhode Island to Kinsale Ireland which is just under 3,000 nautical miles. That run, if made directly does need external fuel. Even though we don't need deck fuel for runs of up to 2,500 miles, as soon as we get above about 2,000 nautical miles, we'll probably fill at least one deck tank to offer more flexibility. More data on these decisions at: mvdirona.com/2017/04/fuel-option-value-speed-safety/.
No, we keep the bladders full until there is room below decks to accept a full bladder load of fuel. Once we have that space with some headroom, we just pump the entire bladder below and put it away. If it's too rough to put it away, then we just leave it sucked down flat on deck. The way the tie downs work is they are fully secure to the boat and the tank is secured to them so nothing will go anywhere and there is no need to adjust anything.
The Nordhavn approach to pricing is to price a good, strong basic boat without electronics and most other equipment including safety equipment on the argument that each owner will make different choices. Some will be crossing oceans and some never will. Some want the very best and some will want adequate. New boat pricing for these boats makes most of this equipment an optional owner installation decision. Over the years, just about every Nordhavn owner elects to get an emergency wing engine, most elect to install active stabilizers, most but not all install lifeboats, some carry vast amounts of spares for repairs at sea or away from civilization but some carry just about none at all. It really depends upon the owners intended usage and, to some extent, their preferences.
The bridge windows are both thicker and far smaller so design to take a heavy hit. We once got hit with a big wave heady South on the east coast of South Africa that hit the front windows so hard it sounded like an explosion. I actually ducked at the wheel. The wave tore the top off one of our forward storage deck hatches. Those front windows appear to be able to take a lot of abuse and the boat builder did not provision them for storm plates.
Just curious and perhaps someone can answer this, from what I understand the Atlantic ocean can produce massive storms and high seas. This particular vessel seems a bit small for trans-Atlantic ocean voyages, how does it brave the high seas and storms that it will invariably run up against ?
Weather can be a problem so ocean crossings are best done during the calmest part of the year. Normally that works pretty well. Here's a video of some of what we saw in the North Atlantic -- its rough but not dangerously so: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html
The boat can easily go 2,500 nautical miles so can cross any ocean without needing deck fuel. At times we have gone as far as 3,850 nautical miles between fuel stops and we often go 3,000 so we do need extra fuel for these trips. The fuel bladders were all purchased Aero Tec Laboratories (www.atlinc.com/) and we're supper happy with them.
The flashpoint on diesel makes it far safer than gasoline but, if a fire develops on the boat and it gets hot, the bladders definitely could burn. Its similar to the boats built in fuel tanks. Below deck, there is 1,750 gallons of diesel housed in a fiberglass. Should the fiberglass start to burn for some other reasons, the diesel will support the resultant fire. The lesson is, on any boat but especially on a fiberglass boat, don't let fires start and fight them early and effectively. Once out of control, the boat will be lost.
It's actually more than a "ton of fuel" below decks. Just a bit more than 6 short tons or 1,750 gallons :-). Your question is why do we need more? Strictly speaking, we really don't. You can do anywhere in the world with our roughly 2,500 nautical mile range. With longer range, bigger runs become possible. We ran non-stop between St. Helena in the South Atlantic and Barbados and that's a 3,760 nautical mile passage. For sure, you can get from Cape Town South Africa to Barbados in a 2,500 nautical mile range boat but the routes are not as direct. More fuel allows more range and more speed for a given distance. We think of fuel as "option value" -- it opens up more possibilities. On this particular crossing, we are going 3,000 nautical miles so really do need some of the extra fuel we were carrying but not all of it. And, if we chose shorter routing through the Azores, we wouldn't need any deck fuel.
That's an important question: "how do you get fuel out of a bladder and into the main tanks?" A common choice is to pump it from the bladder to the tank opening using a portable electric pump. This is a nice simple solution but, in rough water, the tank fuel opening may be awash. What we do is have a bulkhead fitting that is directly plumbed to the fuel transfer pump. On this model, short hoses attached between the each bladder and the bulkhead fittings using camlock connections. When it's time to pump the fuel from the bladders below, I just go down to the engine room and set the valves to pump out the bladders into a specific fuel tank below, then turn on the pump. A couple of hours later, the transfer is done and the fuel bladder is vacuumed down flat and ready to be packed away. It's a super easy to use technique.
@@MVDirona This video popped up as a youtube recommendation and i found it fascinating. I was wondering about this exact issue and would have enjoyed watching a video from your crossing where you did this among other things. To date, this is the only video i have ever seen that displays the extra precautions needed for a crossing since a ship is usually large enough to not need extra precautions, or is too small to make the journey so special precautions are not a consideration. It just isnt something people think to document.
It used to be that the boats that cross oceans where either big boats or sail boats. Small boats for the most part, just don't carry enough fuel. Nordhavn is one of a few that specialized in ocean-capable power boats. Small boats that are comfortable but still small enough to be more affordable and yet still able to carry the fuel needed to cross an ocean.
Hello in Kuwait. We've long wanted to visit the Persian Gulf by boat but unfortunately, there is too much pirate activity ranging 100s of miles off the Somali coast and so, at least for us, it's a higher risk trip than we want to make.
That's an important question: "how do you get fuel out of a bladder and into the main tanks?" A common choice is to pump it from the bladder to the tank opening using a portable electric pump. This is a nice simple solution but, in rough water, the tank fuel opening may be awash. What we do is have a bulkhead fitting that is directly plumbed to the fuel transfer pump. On this model, short hoses attached between the each bladder and the bulkhead fittings using camlock connections. When it's time to pump the fuel from the bladders below, I just go down to the engine room and set the valves to pump out the bladders into a specific fuel tank below, then turn on the pump. A couple of hours later, the transfer is done and the fuel bladder is vacuumed down flat and ready to be packed away. It's a super easy to use technique.
MV Dirona Thanks so much for for this information and your excellent videos. You both are a wealth of knowledge, and it’s appreciated!! If you get a chance, I’d like to know more about the bulkhead fittings...Thanks in advance
Camlock fittings are nice, dual lever snap on fittings that are fluid tight. and popular in fuel transfer applications and many other industrial applications. Some examples: www.camlockfittings.co/.
If I calculated correctly, you took a total 2700 gallons of fuel. That's more than 10 thousand liters. According to the specifications of your boat, that's almost two distances you had to go. Why so much? How much you used from coast to coast?
There are two things going on. The first is manufacturer specifications are usually measures of boat range in flat water and real ocean conditions are remarkably worse. The real world range for our boat at more than 7 kts is 2,500 nautical miles. If you are willing to run much slower, it might be able to be stretched out to the full 3,000 nautical miles we needed to cover. It would be cutting it very close and we wouldn't be willing to do more than 2,500 nautical miles our selves. The second issue is we like having more fuel on board to allow faster crossing speed or deal with mechanical problems that increase fuel burn. As an example, we used less than 1/2 of our tender fuel exploring up the Brisbane river in Australia. We bent the problem which limited our top speed a bit but otherwise didn't seem to be a problem. When we were part way back, we learned that our fuel burn with a slightly bent prop was 30% worse than normal and we didn't have the fuel for the full return trip. There were lots of ways to solve that particular problem on the way back into Brisbane but there wouldn't be in middle of an ocean crossing. We like having more fuel than we need when off shore in a small boat.
They are held on by 4 1/4" machine screws which will take several tons of force but you are right that water is incredibly powerful. If bigger fastners where an option, I probably would have taken it.
People don't understand the difference between crossing the southern Atlantic and the northern Atlantic!!. The two of you ARE LEGENDS!!!
We have crossed both the North Atlantic and the South Atlantic and, that small sample, strongly agrees with your assessment. The North Atlantic can pack a punch. Admittedly our timing for the South Atlantic crossing was more careful since it was a long 3650 nautical miles so they aren't directly comparable but the northern one was definitely more challenging from a weather perspective.
Interesting to see the fuel bladders. I've been running the numbers on taking a Ranger Tug across the Tasman Sea using a cockpit fuel bladder. Nice to see someone else using them also. You guys are a masterclass in open ocean trawling. Keep up the great work. Thanks for the content.
Thanks for the feedback. A great source for fuel bladders is ATL with a broad selection of standard sizes and they also do custom designs. Our experience is that the key to a stable bladder is fully filling it. We have had ours out in heavy weather and they never shifted. As an example of how full we aim to get it, we have a picture of me standing on one where I'm hard sinking in at all. Good luck with your project.
That was so educational, a tad bit of a transatlantic crossing and how to prepare. Thank you
Thanks for the feedback.
this is really cool to see the process of running a boat.
Thanks for the feedback on the video.
This is the best yacht vid I have seen. Tells what reallity is over the walk thoughts. Besides, I have owned half those yacht but always have to stop daydreaming and get back to earning the rent.
Yeah, it's true. There is never enough time for everything.
World's greatest hairstyle......I'm totally serious.
Love the channel. Great content.
Thanks for the feedback on our videos.
Interesting. I always just assumed if your boat couldnt hold enough fuel you couldnt go. I didnt even think about carrying extra fuel bladders! learned alot, thanks for sharing!
It's a common trick from the aircraft sector where short distance planes need to rarely need to do a larger hop. The military is another frequent user where they often need to store fuel at temporary locations. Another popular use of fuel bladders is in high speed sports fishers that need to run out a hundred miles or so to get out past the continental shelf on the US east coast. These are fuel hungry boats running at 20 and sometimes even beyond 30 kts so bladders are frequently used.
I Love the Thoughfulness and planning that goes into your videos. This has taught me quite a few helpful pointers, as I too will become a Yacht Operator.
Thanks for the feedback on the videos.
Dude, you are my hero, I appreciate your Bob Dylanesque all black outfit when fitting the shields... epic and totally something I would do.
Yeah, I've got a bit of a Henry Ford approach to style: any color you want as long as it's black :-).
You two have such a great aura! I love listening and learning from you both! We hope to buy a Nordhavn after I retire and go up and down E and W coasts! More videos please! I’ve watched this one at least 4 times!😳😎😎😎👊👊👊
Good push. We'll get to work on getting another video posted.
Thorough preparation is the key to travel success! Fine!
I agree. And, when doing longer open ocean crossings, choosing a good weather window is even more important.
I've had a little boating experience on friends boats and always enjoyed it---but I've never dreamed or wanted to own a boat until recently watching your Dirona videos.
Absolutely love all the prep work. Thank you so much for making this video!!!!
Thanks.
Thanks for sharing! I've seen pictures of your boat and other Nordhavns, but seeing you crawl around in the engine room really helps understand the scale. Safe travels!
Boats are tight places but most places on Dirona are surprisingly easy to get to. However, as on all boats, there are a few service tasks where more space would really be welcome.
Matt Cross i
Great video to showcase how much better suited sailboats are for blue water crossings. Fuel bladders, storm covers, oh boy. Give me an equivalent length sailboat any day of the week.
It is true that more sailboats than powerboats make the trip but, having crossed every ocean in this boat, there are some upsides in comfort. In storm conditions, it's really nice to be inside a warm and dry pilot house.
@@MVDirona Oh, for sure and everybody to their own of course. You guys do an amazing job and your choice of vessel clearly works for you.
Personally, I tried to love powered boats and never managed to. There's magic to the moment you switch off an engine and the wind takes over. I love how a boat just tenses and relaxes at the same time.
And of course, there are very nice sailboats available with a pilot house. ;)
Absolutely brilliant video's you both do,I have a narrow boat that I travel round the inland canal system in and my favourite part of my trips are crossing tidal rivers and the Wash Boston to the Fens on a calm day of course.Thanks again and keep the video's coming.
Thanks Les. We do plan to post another video this weekend on a night time pass through the Brunswick lock in Liverpool.
What a great boat. A machine built for functionality has a a beauty all its own.
We'll take strong over beauty all day long and we're kind of partial to a vaguely commercial look.
I certainly agree with this comment I love the functionality and I am also partial to the commercial look! What a great vessel!
Great video. I have seen the fuel bladders used before on old DC3's in the Canadian Arctic to get fuel to remote locations.
Yes, fuel bladders are used frequently to extend the range of small aircraft. It's a nice solution and there are a lot of different applications: atlinc.com/rangeextender.html.
We used a 2500 gal bladder on the minesweeper I was on from Long Beach CA to Pearl Harbor during Vietnam.
Fascinating video! Thanks for sharing!
And I couldn’t help but keep thinking “Hey! It’s Robert Plant!!!”
Now to watch the videos of the crossing.....
Most of our ocean crossings where great but we made the North Atlantic crossing at a less favorable time of the year so we saw some weather. Nothing dangerous but it was quite rough: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html
I am amazed that you could easily find the screws for the windows! Thank you for the video. Would love seeing your travels on the seas.
Parts of the North Atlantic crossing is in this video: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html. It's a bit rough but you can find lots of relaxing ocean crossings up at: th-cam.com/users/mvdirona.
I really learned a lot thank you. He explains really good what he does.
Thanks.
Yes I was also wondering how you transfer your fuel from your bladder. What a great idea. I've never seen fuel bladders before now.
The fuel bladders are connected to a bulkhead fitting via short fuel hoses with cam lock fittings. There is a fuel transfer pump inside the boat that is responsible for pumping fuel between tanks. From inside the boat, the fuel can be transferred from the bladders into the tanks below. More details on the process here: mvdirona.com/2012/12/fuel-for-the-crossing/.
Long range fishing on a smaller boat people will head out on a loop drop a bladder with a beacon in the ocean do your loop , refuel load the bladder and head back in
I hadn't heard of this before but I suppose diesel is lighter than water so it would float and so it would work. Makes sense.
Just subscribed! I love watching nordhavns in their element, one day I hope to have a nordhavn of my own! Coming from a guy that has no experience in owning a boat, I have to say that nordhavn yachts are the best trawlers out there, and that's saying a lot... Lol love your videos, keep up the good work!
Great organization and video. And a sparkling clean lazz! Bravo!
you are my new heros !! real skippers ..... not a mickey mouse bayside captain !! impressive !!
Y'all are so blessed to joy coursing across the ocean this way.... I've loved large boats as long as I can remember, but my wife of 40+ years is as scared of water as I am heights...LOL. I got her in a 14 foot fishing boat out on a small lake one time. All was go until the motor failed and the wind kicked up. I tried to paddle the boat back to shore but the wind was blowing us into the middle of the inland lake. She was freaking out. A couple of guys in a canoe towed to a near by dock and gave me a ride to get my truck and trailer. That next day the boat was sold!!! LOL... But I use to get out on out big old Lake Michigan on a friends 30 foot charter boat when ever the chance came my way... But no more physically able to do it. but at my age riding my 3 wheel motorcycle now and then is fun enough...LOL,LOL.. Her and I have ridden motorcycle for 38 years together. But she has always had to ride her own Harley which she's in love with...LOL...
Oh well I've rambled on enough. Have fun, be safe, and most of all be blessed as y'all cross the ocean and your time in Ireland... May the Good LORD bring y'all into safe harbors...
I'll be laying here watching for your vlog updates... BBE...
I'm not sure motorcycles are safer than long range cruisers but it's super hard to have an interesting life without accepting some risk.
We're currently enjoying a nice slow run south through Scotland's Caledonian Canal: mvdirona.com
you are not a kid ,but you move around like ONE !!!!!! always believe a big boat is the best way to keep one fit !!!!! it takes TONs of calories keep a yacht in good shape !!!
I agree that, if you take care of your own boat, it does take some activity. Potentially an even more important factor is going to new places and seeing new things tends to make you more active both mentally and physically.
I sure as hell am a kid, whenever I’m on a ship, I’ll be walking around the whole thing but mostly at the bow or stern. Sound of the stern’s volume is highly increased from the engine.
I'm the same way when touring ships and, over the years, have toured some very interesting examples:
*Oil Tanker: mvdirona.com/2019/09/oil-tanker-tour/
*Scalloper: mvdirona.com/2016/11/on-board-a-canadian-scalloper/
*Container Ship: mvdirona.com/2012/06/on-board-the-hanjin-oslo/
*Cruise Ship: mvdirona.com/2016/02/behind-the-scenes-on-the-westerdam-2/
*Steamship: mvdirona.com/2019/07/historic-steamship-tour/
*Nuclear Submarine: mvdirona.com/2016/05/uss-california-distinguished-visitor-embark/
*Cable Layer: perspectives.mvdirona.com/2017/01/cs-responder-trans-oceanic-cable-layer/
*Ice Breaker: mvdirona.com/2015/01/on-board-the-aurora-australis/
*Arctic Research Vessel: mvdirona.com/2015/10/on-board-the-marion-dufresne/
This guy is my spirit animal 🤙
0:30 I see You don't have a flopper stopper on the starboard side. Is one flopper stopper on the port side as effective as when there are two, or is there a difference, and if so, is there a big difference?
There is a flopper stopper on both sides of the boat but we frequently only use one. A single flopper stopper seems to have about 70% of the anti-roll forces as using two. I suspect in the limit when it's really rough 2 floppers is 2 about twice as effective as a single flopper stopper. But, in more mild conditions, one is very effective and dome boats elect to only install one.
Hey guys, great boat and interesting video. I like your faith in the crane ! Keep living the dream.
Very interesting video, thanks for sharing.
Thanks for the feedback. Glad you enjoyed it.
Really nice, everything has its place aboard your boat, electronics and electrical lay out is a electrical engineering feat! can’t understand the 41 miserable souls who put thumbs down?
Excellent video. I am impressed with your videos. they are factual and show the amount of real prep that is required for a ocean passage. thank you for sharing your journey.
I'm struck by the passion with which you pursue your dream. This is the second video of yours I've seen. The mind boggles at what effect your impressive knowledge and self-preservation skills would have if they were refocused from self-indulgence to more selfless pursuits.
I work full time as an engineer but I get paid for that so it probably doesn't qualify as selfless :-). This is my day job: th-cam.com/video/AyOAjFNPAbA/w-d-xo.html.
Billy Connolly putting the window cover on, nice 😉
I was thinking it was Brian May, but yeah, I see Billy there.
Great content, well narrated. Thanks for sharing.
Of all the videos covering preparations for making a yacht sea ready yours was the most complete. The yacht turned out to be a Nordhavn a well thought out an complete package.
The crossing was one of our rougher ones and we had a couple of mechanical issues (th-cam.com/video/guEnTp2a6Sc/w-d-xo.html) but most of the time it's a nice relaxing run.
Nice video. How do you transfer fuel out of the bladders to present to the engine?
The transfer system is a fairly nice setup that avoids having the fuel tanks open to the weather or there being any risk of a spill. Nobody even has to be outside. There is a camlock connection on the bulkhead and on each bladder. A short hose connects the bladder to the bulkhead connection. Once there is space in the below decks tanks, we open the safety valve on the tank and then use the fuel transfer pump on the boat (it's use to move fuel around between tanks or to filter fuel in a given tank) to transfer the fuel from the bladder to the tank. This allows a risk from transfer and the bladder can be vacuumed down flat so it's totally empty and all fuel is filtered before it's put below decks as part of this process.
@@MVDirona very nice setup indeed. I always enjoy hearing about long haul journeys like this and the mechanics and prep that goes into them!
Getting small boats able to comfortably cover long distances takes a bit of work and thought but, clearly, starting out with a well designed and well thought out boat is crucial.
Really enjoy this video👍🏻👍🏻👍🏻👍🏻 thank you for taking the time to post it. Safe journey
Thanks for the lovely video
question:
what method did you use to pump the fuel from the Bladders to the vessel main fuel tanks!?
Thanks again and keep them coming
Be safe
& Safe sailing "boating"
Good question. The boat has a fuel transfer system designed to be able to move fuel between the 4 below deck fuel tanks. What we did was add another input to the fuel transfer pump manifold that connected to a fuel hose running to an exterior bulkhead at the back of the boat. There are short hoses that run between the exterior on deck fuel tanks to the bulkhead fitting.
To pump out the fuel tanks, a manual safety valve needs to be opened on each tank after which, the fuel bladders can be pumped into the tanks below by going down to the engine room and decide where to pump the fuel, set the valves correctly and engage the fuel transfer pump. This has the advantages of not forcing the operator to be outside on deck, there is no risk of getting water into the fuel system, and you can evacuate the bladders fully. The ladder is particularly helpful in that fuel bladders with even tiny amounts of residual fuel are heavy and hard to pack away whereas fully emptied bladders are easy to deal with.
@@MVDirona thanks for the prompt reply, what a brilliant way.
Love the risk assessment part of thinking.
Great 👍🏼 job
Thanks for sharing such technical specks
It is really informative.
great video and very innovative to use a bumper as a exhaust cover.
How about adding a downward curve to that exhaust. Done
Very informational video! I have to ask....how many port side pieces of plexiglass have you dropped while doing the port side from the tender?...lol
I haven't lost one yet but enough people have argued that just turning the boat around in the slip is probably faster and is definitely easier. We may just give in to low tech solutions and declare that the new standard operating procedure :-).
Well done. I enjoyed your video and even learned a bit. Thank you.
Just what I was expecting to find once on you tube ! Good shots, well done.
Thanks!
How do you transfer the fuel from a bladder to the engine. Thanks for the interesting video.
It's a pretty cool set up where, before leaving, a custom made hose is attached to each bladder by cam lock fittings and then connected to the aft bulkead also by cam locks. Then when it's time to transfer the fuel we just adjust the fuel manifold in the engine room to "Fuel Bladders" and do the transfer without going outside. Much more detail in this posting: mvdirona.com/2013/12/dirona-fuel-manifold/.
@@MVDirona what is your total on board fuel, l was guessing 3,400 usg?
Below decks we carry 1,750 US gallons and, when fully loaded with deck fuel, can carry 2,710 USG.
Fun video guys, thanks for sharing! I know you had a problem with flooding on the crossing but I'm sure James and Nordhavn will figure out the best solution you can come up with. I've enjoyed your Blog for a few years now. Doubt I will ever be able too buy a vessel like this, but it is fun to learn anyway. James attention to detail would do well in the Submarine Force, he'd fit right in. I spent 3yrs on a Submarine and I'm jealous James got to go out on the new Virginia Class Submarines. I haven't had the privilege. I'd love to see the changes made in the last 30yrs from my old Sturgeon Class Submarine.
I feel super lucky to have had the opportunity to take a trip on the USS California. I even got to crawl to the end of one of the forward torpedo tubes and sign my name on the outer door. Torpedo tubes look fairly big until you get down to the end :-)
Very interesting and informative video. The smallest ship I crossed the Atlantic on was the Queen Mary. Hope you had a good one!
There is a lot to be said for the Queen Mary approach. When taking on weather, size really does matter. Small boats put control in your hands, give us flexibility to go where we want to go when we want to go there but the weather is a downside risk we need to keep an eye on. We have crossed oceans many times but this one was rougher than usual: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html.
I'll post the changes we made as a consequence of that trip sometime this week or next to mvdirona.com. We think these engineering changes are sufficient to make the weather we saw on our North Atlantic crossing a non-issues.
Enjoy your trip and God bless you.
What a great video! Very interesting. Thanks for sharing that. Keep em coming.
Thanks.
Did anyone else think that the first words out of his mouth would be, "great scott Marty!, if we don't fix the time machine we'll never get back to the future."
Thanks for a 'Reality Tube' on long distance voyaging. This is vital information for would-be boaters to come in contact with. Shipbuilder's crossing videos don't show the steps needed to fully secure windows at the cost of natural lighting and ventilation. What with the move to bigger windows at each level, I have been interested in just this detail.
You nailed it. All decisions in boat buildings are compromises. Small windows are better at sea but you mostly aren't at sea. Large windows are wonderful most of the time but aren't safe in extreme conditions. The solutions I like best are very thick windows or protection with storm plates.
A broken window in storm conditions could end it all so it's worth being careful.
How about attaching a safety line to one of the bottom holes of the storm plate when attempting to install on the port side. That may save having to replace/dive for the plate in the event it slips. Once you have the top two screws in simply untie the safety line and carry on inserting the bottom screws. Just a friendly suggestion from someone who has dropped many things (mistakenly) into the drink!
I think your right that it would be easy to drop a panel and a safety line wouldn't be that difficult to install. It's a good suggestion.
Great stuff...I love videos like this...Thank you
what a nice video (for a skipper like me , i guess !!) what a nice toy is that little ship !
Very interesting video. Man, you really need a ton of knowledge and a lot of work to live this life safely.
It's hard to do it for many years without learning a quite a bit and I'm the sort of person that wants to know the "why?" behind everything but it's absolutely not required to enjoy the lifestyle at comfortable levels of risk.
Accumulated, first hand knowledge tends to stick with me best. Thanks for sharing. _Comfortable levels of risk._ Lol.
How do you manage drawdown of the bladders? Fill the main tanks several times or wait till you can drop the entire stern bladder contents into each tank at one time? How do you transfer the fuel? How do the full bladders affect your stability?
Good question. We run until we have room below decks to bring a full bladder down. Once there is room to bring one down, we do it.
The bladder pump down is super easy. There is a cam lock fitting on the bulkhead so pump down just requires plugging in the hose and, once that done, the tank can be pumped down without going outside. It's transferred by the central fuel transfer pump (same pump used for moving fuel between other fuel tanks) with the nice side effects of: 1) all fuel is filtered on the way below, 2) there is no chance of water ingress or fuel spills, and 3) don't need pumps outside etc.
I've posted the fuel bladder stability data below but the short answer is it can still pass ISO Category A All Oceans when running with full bladders: mvdirona.com/2019/03/deck-fuel-and-vessel-stability/
great set of videos!! could i suggest you number them in the title it would make watching them in order easier
Of course there is an chronological order of production but, with all the different topics covered, we don't really expect them to be watched in any specific order but I can see the upside of numbering them going forward. Thanks for the suggestion.
Just come across your video I subscribed because I'm thinking about getting one myself as there is only 2of us. We would like to stick around and enjoy your everyday experiences have a nice trip.
That's the way we travel as well Billy. Just the two of us.
Probably easier to move the boat 6' to port to install storm windows from dock?
Probably true. It was an experiment because to avoid turning the boat around as we normally do. It takes some time to drop all the lines, unplug the boat, and then move all the lines to the other side. Then do it again. But, yes, doing that probably would have been easier.
Never realized Robert PlNt went cruising.😁
Hoping all is well. Noticing the weather for crossing not good !
Your right. There is currently a hurricane approaching Kinsale Ireland (where we made landfall after our North Atlantic crossing) and, even where we are currently are in Scotland (mvdirona.com) we have been seeing some big barometer swings.
I had no idea fuel Bladders existed very cool
Yeah, bladders in used frequently in military applications when deploying forces to new locations quickly. They are used to reposition short and medium range aircraft longer distances. They are in frequent use in the sports fisher fleets that need run longer distances to get to the pelagic fish. They are great tools to extend range.
I liked it but can’t understand how you fix the storm catcher plexiglass??
The permanent window frames in the boat have 1/4" threads and cap screws run through holes in the plexiglass storm plates into the permanent sockets.
PS, I was fascinated by the fuel bladders for long voyages. Really interesting as I only know about aviation applications. How do you pump into the tanks? Do you cross pump - ie run port tank low then pump starboard bladder into port tank to maintain trim?
Jjaus, we have a fairly simple fuel transfer system for the bladder fuel where we connect a cam to a permanent fitting on the bulkhead via a short hose section to a cam lock on the bladder tanks. When it is time to pump the fuel, the standard fuel transfer pump moves the fuel from the bladder, through the transfer filter (25 micron RACOR FPO-10), and then is directed into one of the main tanks. This has the advantage of allowing fuel to be pumped with nobody outside, doesn’t require the tank filler to be open to water ingress, filters all fuel as it leaves the bladders, and allows the bladders to be pumped completely dry so they are light and easy to handle.
When fueling the main tanks, the fuel is brought in directly. We filter all fuel that is transferred from the main tanks to the day tank (wing engine) or the supply tank (all other engines) using the same 25 micron RACOR FPO-10) transfer filter and high capacity fuel pump.
When transferring fuel we pump from the left side bladder to the left side tank and the same on the right side. This keeps the fuel on the same side so the fuel movement doesn't affect trim. The stern just rises slightly.
If you are interested, there is a lot more information on the fuel management and transfer systems used on Dirona here: mvdirona.com/2013/12/dirona-fuel-manifold/
Ahh, makes sense. Will read your link tomorrow (sans red wine, it's Sat night here and almost bed time). We're planning buying a Prestige 550 fly and the CE rating is B. If we want to motor from EU to Carribean via N America, is it worth all the hassle and money or paying to transport it, then fly over? So many variables and new skills needed for trans-oceanic voyages. We are frankly too scared to motor from Australia to Europe through all the piracy zones, so have decided our adventure will begin somewhere in the Med.
Like you, we won't go anywhere near to any reported pirate activity. Never within 100s of miles. There are routes from Australia to North America that stay away from all pirate activity but it will force you to round South Africa which requires care with weather. We've done it and you can get lots of detail on the trip up at: mvdirona.com/Trips/indianocean2015/IndianOcean1.html. This links shows the Indian Ocean crossing but you can see the full trip by moving the map out to show the world and selecting the leg you wish to see in more detail.
Certainly starting in the med is an easier plan and, generally, the run between Australia and North America is a lot of open ocean time.
Do you still travel as much with diesel over $5 a gallon now!! I just love all your technical explanations!
You're right it is getting expensive to fuel a boat but we never found diesel to be one of the dominant costs. Even 5 years ago we were paying nearly $7/gal in some locations (e.g. Northern Australia) and we wish it were lower but it was never even close to our biggest cost.
When operating a boat at displacement speeds, fuel burn can be kept relatively small. Lower costs would definitely help but world cruising is still practical at higher fuel costs.
Wonderful video. I may have missed it, but do you use the bladder fuel first to free up deck space?
We do move the fuel from the bladders down below as soon as we can. It does free up deck space but the primary reason we move the fuel down below is that is the most stable configuration for the boat. Just the below deck fuel load weighs more than 5 tons. For stability reasons, we want this weight as low in the boat as possible. So, as soon as there is space below, we pump the bladders empty, clean them up, and put them away. If you are interested in more details: mvdirona.com/2019/03/deck-fuel-and-vessel-stability/.
Wish you mentioned how much all of that fuel cost!
It's been awhile so I don't have the exact number but I suspect it will have been around $5,000. As you know, the price of fuel is much more in other parts of the world and, just filling the boat tanks without bladders in Australia cost over $7,0000. It can get pricey but it doesn't happen often. We have only filled the tanks twice this year and both times they weren't that low (over 1/3).
That’s incredible! Thanks for sharing.
Great stuff. I'm glad that you guys took the time to show us how you prep your boat for long passages... I especially love the utilization of your fuel bladder for extra fuel for those far away excursion. I think that that's a great idea. Good for you guys! Furthermore, I would like to take this opportunity to state that I too would love to know, if you don't mind of course, how you transfer the fuel to your main tanks. I've visited the web site in which sells those bladders and seen that they have electrical powered fuel fill hoses and wonder if that's what you guys use?
Thanks for the comment Robert. We use a cool system where a passive hose is cam locked onto a permanently installed bulkhead fitting on one end and the fuel bladders on the other. Using the fuel manifold in the engine room, I can just pump the fuel below without going out side. There is a picture of the fuel transfer system in this article: mvdirona.com/2013/12/dirona-fuel-manifold/
I've outlined a bit more detail on the transfer process and advantages here: mvdirona.com/2017/10/preparing-dirona-for-the-north-atlantic-crossing/#comment-214735
Most enjoyable video--thankyou
Thanks for the feedback.
I will let James captain my ship anytime! Cool Dude!!
Does the fuel in the bladders go to the engine or do you transfer it into the boats tanks ?,,Love your Adventures
As soon as we have 400 gallons used below, we pump the forward tank down. And then, once we use up enough to bring aft tanks below we do them as well. We basically clear the decks as soon as possible since it's bad for boat stability to have main tanks low with fuel on deck.
It feels kind of weird to have full tanks, 1,000 nautical miles off shore and 7 days after leaving port.
Curious to know how much it costs to fuel stateside with the bladders. Also I thought the 52 and the 60 had enough fuel capacity to cross Atlantic? ...do you use the bladders to save fueling costs in Europe (must cost way more) or is it a necessity to have the extra for piece of mind? I ask as my wife and I are thinking of a Nordhavn 60 for our retirement..the main reason is for it's passagemaking ability as we have family all over the globe we wish to visit....your videos have been a great help. Thanks. Carl
Yes you are correct that both the 52 and the 60 can easily cross the Atlantic. Real range in ocean conditions is almost always far shorter than computed miledge but, at reasonable speed, Dirona can do 2500 nautical miles without bladders and 4000 with them.
On fueling costs, it depends how much you need and the price but it carries 1750 gal without bladders and 2650 with them.
@@MVDirona wow...big difference in range. Having read a bit of you blog with the water ingress during your trip do you think it is still worth running the bladders ( think you said you struggled with access to lazerette to determine where the ingress was coming from) or do you thing the extra weight actually helped with stability in the bigger seas?
I'm pretty sure the bladders played no part in the water ingress problem but you bare right that they did block access to the locker that was leaking making it more difficult to correct the problem.
The problems have all been mitigated:
mvdirona.com/2017/12/alarms-at-115am-follow-up/
With those changes in place we wouldn't hesitate to use the bladders when we need additional range.
Very well done video !thanks
Nice videos and what an amazing boat. But storing more than 3 tonnes of fuel on deck doesn't that mess with the stability?
In this operating mode, the boat calculates out to continuing to meet CE Class A Ocean with the deck fuel. It actually can survive the main tanks being brought down to near empty with fuel on deck and remain CE Class A Ocean. It won't quite make it with empty tanks but, as I said, we don't run it this way. When we have 360 gallons of space below decks, we move the forward tank load below. Then once we have 600 gallons below decks, we move the aft load below. The goal is to have this fuel below decks in 7 to 10 days while weather reports remain fairly accurate.
Dirona is CE Class A Ocean even when using fuel bladders. I'll post a more detailed blog on this at mvdirona.com.
Thanks for reply. Your Nordhavn is an impressive boat that's for sure. I've read your blog, and you had issues with flooding and a lot of water on the stern deck on your north Atlantic crossing. And I can hear you say in the vid that she's deep in the water after the fuel is stored, don't you think that could mess with the "self-draining" system on your stern deck and cause the flooding?
Thank you, I've never heard of dead plates before.
It's the protective cover (essentially a shutter) over the windows with the design point being a broken window would remain sealed and not take water.
How many days to get across?
Our crossing was 17 days but there are more direct routes that are shorter. We went from Newport Rhode Island direct to Kinsale Ireland. That's 2,800 nautical miles. The downside of that routing is it's further north than the common one and we went early in the year so we could enjoy the summer in Ireland and Scotland so we saw 3 low pressure systems and some rough water on that crossing: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html.
MV Dirona brave crossing!
Our longest cross ocean run was St. Helena to Barbados which was just under 26 days to cover 3689 nautical miles: mvdirona.com/2016/02/barbados-arrival/. Long enough that we needed to shut down the main engine for an oil change on the way across :-).
I didn't know you can store additional fuel like that ! Interesting.
Yes, fuel bladders are heavily used in military applications where they want a quick base. They are used in military helicopters where they have special self healing properties that can allow them to take a shell and continue to hold fuel. They are used in race cars to allow massive collisions with less likelihood of fuel spills. They are used in recreational aircraft applications to move short range aircraft over longer distances. They are used by high horsepower sports fish boats to make long runs to deep water for pelagic fish hunting. And, of course, they are used by recreational boaters to increase range. Not super common but they can make a big difference. We have a 2,500 nautical mile range with good reserves in rough water which is sufficient to make any crossing but you need to chose routings carefully. Carrying deck fuel, we can reach 4,000 nautical miles under the same conditions.
Another important limitation is vessel stability. Carrying deck fuel will reduce the stability of the boat and the amount of fuel that can be safely carried by a given boat depends upon boat design and worst conditions encountered. Here's some more data on our boat and the impact of deck fuel on stability: mvdirona.com/2019/03/deck-fuel-and-vessel-stability/.
@@MVDirona thank you for the information. I only knew about the land-based applications of bladders and also in combat helos. I'm an engineer by trade so I was indeed wondering about how bladders would raise a boat's center of gravity. I would expect you use the fuel from the bladders first, but I've just watched one of your videos where you explain your fuel system and it doesn't seem that's what you're doing. But maybe it isn't necessary, I suppose the limits you mention take into account the weight of the fuel in the internal tanks.
We effectively do what you are saying. We run the main tanks down 400 gallons, and then pump down the 360 gallons forward. Then we go until we have 650 gallons available below decks and pump the 600 gallons on the aft deck down. At that point, there is nothing left on deck (other than empty fuel bladders).
@@MVDirona thank you, nice to know I had the right intuition. Those Nordhavn yachts are really starting to interest me. It's probably going to be my retirement plan, in another 20 years or maybe even sooner.
A bit before retirement might make sense in that it takes time to know what you like, make sure you actually like boating, and then get a boat equipped and setup as you like for the kind of trips you plan. But, overall, your plan sounds like a good one.
When you were handling the storm covers for the side windows, i thought if they had a handle it would be easier. If it slips you have to get the scuba gear out.
I've considered using the suction holders used to install heavy glass plates in buildings. Having a handle would make handling those big, heavy plates much easier. I'll have to come up with something.
why wouldn't the port hole covers go on the outside to protect the windows?
Your right that, in many ways, they would be better on the outside. Either inside or outside, the protect the boat from flooding but, on the outside, they protect the window as well. Presumably they are attached on the inside because they are so much easier to install there and they can provide the same last line of defense against flooding in either position.
wondering why you didn't just push over to the dock next to yours for the 30 minutes it took to put the storm plates on?
We've been experimenting with different ways to install these port slide storm plates. Given the spot beside us in the marina was available, I think you are right that just moving over would have been easy/faster.
Great boat🥰
How to you transfer the fuel from the bladders? Do you have a portable manual pump? Would love to see that process please.
The boat has multiple fuel tanks and is equipped with a fuel transfer pump. It's a high speed electric pump that can move fuel from one tank to another. When the transfer pump transfers fuel it also forced it through a filter so the fuel can be "scrubbed" but pumping it from a tank and back to the same tank. I've added another connection on the fuel transfer manifold that connects to a bulkhead on deck. There are short hoses with quick connect fittings that connect between the on deck fuel tank and the bulk head. Once this is in place, you don't even need to go outside to tranfer fuel from the deck tanks to the main fuel tanks and there is no risk of open tank fittings allowing water ingress. It works fairly nicely and allows the fuel bladders to be pumped down flat removing all the fuel completely which makes them lighter and easier to store.
i thought these nordhavns can do that distance on internal tanks only?
That's an important point A Nordhavn 52 can go anywhere in the world and cross any ocean but you don't have complete flexibility on routing. Fuel allows different routes, higher speed, or opens more options.
The most important point to keep in mind is that most published range data you see is wildly optimistic. Ocean swell tends to reduce fuel economy greatly. As part of our boats original commisioning, John Deere engineers where on board and they did a two way (both directions) fuel economy test at 100 RPM increments. Using this data, our range with a 10% reserve was around 1,400 nautical miles at wide open throttle of 9.5 kts, 3,790nm at 6.5 kts, 4,500nm at 6kts, and an incredible 6,770nm at 5kts.
Clearly you don't need more than 4,500 nautical mile range but ocean conditions are very different and we've learned our range is 2,500 nautical miles. This is excellent but there are times when you might want more. With deck fuel, our range is 4,000 nautical miles. The trip you were asking about was Newport Rhode Island to Kinsale Ireland which is just under 3,000 nautical miles. That run, if made directly does need external fuel.
Even though we don't need deck fuel for runs of up to 2,500 miles, as soon as we get above about 2,000 nautical miles, we'll probably fill at least one deck tank to offer more flexibility. More data on these decisions at: mvdirona.com/2017/04/fuel-option-value-speed-safety/.
Very well done. Must you keep readjusting the tie downs on those bladders as the fuel is used up?
No, we keep the bladders full until there is room below decks to accept a full bladder load of fuel. Once we have that space with some headroom, we just pump the entire bladder below and put it away. If it's too rough to put it away, then we just leave it sucked down flat on deck. The way the tie downs work is they are fully secure to the boat and the tank is secured to them so nothing will go anywhere and there is no need to adjust anything.
Thank you. Another good informative video.
I wonder if all of this safety gear is included with the purchase of the boat!
The Nordhavn approach to pricing is to price a good, strong basic boat without electronics and most other equipment including safety equipment on the argument that each owner will make different choices. Some will be crossing oceans and some never will. Some want the very best and some will want adequate. New boat pricing for these boats makes most of this equipment an optional owner installation decision.
Over the years, just about every Nordhavn owner elects to get an emergency wing engine, most elect to install active stabilizers, most but not all install lifeboats, some carry vast amounts of spares for repairs at sea or away from civilization but some carry just about none at all. It really depends upon the owners intended usage and, to some extent, their preferences.
I imagine it depends on how much and where you sail. I was actually referring to the window plates and port hole covers in general!
The port hole covers are standard but the storm plates are an additional cost option.
Great insight and education, thank you
I am surprised you did not protect the bridge windows ??
The bridge windows are both thicker and far smaller so design to take a heavy hit. We once got hit with a big wave heady South on the east coast of South Africa that hit the front windows so hard it sounded like an explosion. I actually ducked at the wheel. The wave tore the top off one of our forward storage deck hatches. Those front windows appear to be able to take a lot of abuse and the boat builder did not provision them for storm plates.
@@MVDirona Thanks for comprehensive reply, much appreciated. Lovely videos, good luck to you both.
Another great video, thank you for the great info.
Thanks for the feedback on the video.
Just curious and perhaps someone can answer this, from what I understand the Atlantic ocean can produce massive storms and high seas. This particular vessel seems a bit small for trans-Atlantic ocean voyages, how does it brave the high seas and storms that it will invariably run up against ?
Weather can be a problem so ocean crossings are best done during the calmest part of the year. Normally that works pretty well. Here's a video of some of what we saw in the North Atlantic -- its rough but not dangerously so: th-cam.com/video/guEnTp2a6Sc/w-d-xo.html
Do the bladders come with the boat, or do you rent them, or did you have to buy them?
The boat can easily go 2,500 nautical miles so can cross any ocean without needing deck fuel. At times we have gone as far as 3,850 nautical miles between fuel stops and we often go 3,000 so we do need extra fuel for these trips.
The fuel bladders were all purchased Aero Tec Laboratories (www.atlinc.com/) and we're supper happy with them.
It is probably a dumb question but aren't those bladders dangerous because of fire hazard?
The flashpoint on diesel makes it far safer than gasoline but, if a fire develops on the boat and it gets hot, the bladders definitely could burn. Its similar to the boats built in fuel tanks. Below deck, there is 1,750 gallons of diesel housed in a fiberglass. Should the fiberglass start to burn for some other reasons, the diesel will support the resultant fire. The lesson is, on any boat but especially on a fiberglass boat, don't let fires start and fight them early and effectively. Once out of control, the boat will be lost.
JENNIFER and James please could you tell me why you need all these fuel bags I thought your ship carries a load of fuel in its hull.
It's actually more than a "ton of fuel" below decks. Just a bit more than 6 short tons or 1,750 gallons :-).
Your question is why do we need more? Strictly speaking, we really don't. You can do anywhere in the world with our roughly 2,500 nautical mile range. With longer range, bigger runs become possible. We ran non-stop between St. Helena in the South Atlantic and Barbados and that's a 3,760 nautical mile passage. For sure, you can get from Cape Town South Africa to Barbados in a 2,500 nautical mile range boat but the routes are not as direct. More fuel allows more range and more speed for a given distance. We think of fuel as "option value" -- it opens up more possibilities.
On this particular crossing, we are going 3,000 nautical miles so really do need some of the extra fuel we were carrying but not all of it. And, if we chose shorter routing through the Azores, we wouldn't need any deck fuel.
How do you transfer the fuel that you put in those bladders so that it can be used by the engines?🙋♂️😷👏❤️👌🏼
That's an important question: "how do you get fuel out of a bladder and into the main tanks?" A common choice is to pump it from the bladder to the tank opening using a portable electric pump. This is a nice simple solution but, in rough water, the tank fuel opening may be awash. What we do is have a bulkhead fitting that is directly plumbed to the fuel transfer pump.
On this model, short hoses attached between the each bladder and the bulkhead fittings using camlock connections. When it's time to pump the fuel from the bladders below, I just go down to the engine room and set the valves to pump out the bladders into a specific fuel tank below, then turn on the pump. A couple of hours later, the transfer is done and the fuel bladder is vacuumed down flat and ready to be packed away. It's a super easy to use technique.
@@MVDirona This video popped up as a youtube recommendation and i found it fascinating. I was wondering about this exact issue and would have enjoyed watching a video from your crossing where you did this among other things. To date, this is the only video i have ever seen that displays the extra precautions needed for a crossing since a ship is usually large enough to not need extra precautions, or is too small to make the journey so special precautions are not a consideration. It just isnt something people think to document.
It used to be that the boats that cross oceans where either big boats or sail boats. Small boats for the most part, just don't carry enough fuel. Nordhavn is one of a few that specialized in ocean-capable power boats. Small boats that are comfortable but still small enough to be more affordable and yet still able to carry the fuel needed to cross an ocean.
good luck and be safe , wacthing from kuwait 😉
Hello in Kuwait. We've long wanted to visit the Persian Gulf by boat but unfortunately, there is too much pirate activity ranging 100s of miles off the Somali coast and so, at least for us, it's a higher risk trip than we want to make.
Fantastic....
How do you get the fuel from the bladders to the main supply tanks? Great videos by the way. Thanks for producing them!!
That's an important question: "how do you get fuel out of a bladder and into the main tanks?" A common choice is to pump it from the bladder to the tank opening using a portable electric pump. This is a nice simple solution but, in rough water, the tank fuel opening may be awash. What we do is have a bulkhead fitting that is directly plumbed to the fuel transfer pump.
On this model, short hoses attached between the each bladder and the bulkhead fittings using camlock connections. When it's time to pump the fuel from the bladders below, I just go down to the engine room and set the valves to pump out the bladders into a specific fuel tank below, then turn on the pump. A couple of hours later, the transfer is done and the fuel bladder is vacuumed down flat and ready to be packed away. It's a super easy to use technique.
MV Dirona Thanks so much for for this information and your excellent videos. You both are a wealth of knowledge, and it’s appreciated!!
If you get a chance, I’d like to know more about the bulkhead fittings...Thanks in advance
Camlock fittings are nice, dual lever snap on fittings that are fluid tight. and popular in fuel transfer applications and many other industrial applications. Some examples: www.camlockfittings.co/.
If I calculated correctly, you took a total 2700 gallons of fuel. That's more than 10 thousand liters. According to the specifications of your boat, that's almost two distances you had to go. Why so much? How much you used from coast to coast?
There are two things going on. The first is manufacturer specifications are usually measures of boat range in flat water and real ocean conditions are remarkably worse. The real world range for our boat at more than 7 kts is 2,500 nautical miles. If you are willing to run much slower, it might be able to be stretched out to the full 3,000 nautical miles we needed to cover. It would be cutting it very close and we wouldn't be willing to do more than 2,500 nautical miles our selves.
The second issue is we like having more fuel on board to allow faster crossing speed or deal with mechanical problems that increase fuel burn. As an example, we used less than 1/2 of our tender fuel exploring up the Brisbane river in Australia. We bent the problem which limited our top speed a bit but otherwise didn't seem to be a problem. When we were part way back, we learned that our fuel burn with a slightly bent prop was 30% worse than normal and we didn't have the fuel for the full return trip. There were lots of ways to solve that particular problem on the way back into Brisbane but there wouldn't be in middle of an ocean crossing. We like having more fuel than we need when off shore in a small boat.
maybe i'm not appreciating the fasteners, but heavy plexi for water that could break windows, held on by 4 screws for each window ? that seems light.
They are held on by 4 1/4" machine screws which will take several tons of force but you are right that water is incredibly powerful. If bigger fastners where an option, I probably would have taken it.