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Hey - what a bold move. We had dagger boards on our crowther and replaced them with fixed "minikeels". Our cat was already extended to 54 ft with sugar scoops. In the process we moved the keels more towards the stern as our cat had a tendency to turn into wind (weather helm). The surface area/wet area was kept about the same as it was with the daggerboards. Keels were moved closer to the stern and now we enjoy much better performance. Plus easier to sail as one does not have to work the daggerboards...interesting to see how this will affect on your upwind performance. Maybe one knot increase is on conservative side going downwind. All the best and please keep making these videos! Arto Sailing Catamaran Paws
Arto! Great to hear from you! Hope the hawksberry is treating you well. It was a bold move and we are excited to see if it all pans out the way we hope. Mini keels would make things easier, wow so you have 4 ft extensions! Hope to see you out there. Sam
Hi Sam. Well done for cutting off the water brakes. I had to read all your comments to find that they were an addition to the original design and therefore cutting them off has no structural impact on the integrity of your boat. I could not understand why you had dagger boards and skegs as cats are designed with one or the other. Belt and braces as my bridging design engineers would call it. 😂
Totally agree with what you've done. The sheer thickness of those skegs is enough to scare the speed gods away lol. But if they weren't parallel then it's like driving with a hand brake on. The weight will make a slight difference but then again 60kg is just one extra pretty girl and I'm sure that's gonna happen haha so let's forget about the weight saving. You'll save loads on drag, draw less which is a real bonus and go faster toboot, win win all round. You have your welder guy there, have him check the structure/support at the low parts of the hulls, they would have originally been strengthened to take the boats weight via the skegs, I'd be surprised if you couldn't beach the boat as it is, you may need a folding prop if your prop blades are the lowest part of the hull . But well done for even looking for and finding the issue, I doubt many people would even do that and then to fix it.... Well in my book your daily dairy just got a gold star ⭐ Cheers guys 🍻
Hahaha love your answer. I must say I already have 2 pretty girls on board which is enough for me lol. Surprisingly they didn't add any extra supports but it may be because we are aluminium and strong enough lol. Thanks again for your comment it has made my morning. -sam
Yep I was one that questioned the removal of the skegs last week, and I'm still questioning it this week. Your boat, your choice. But I see a lot of disadvantages for a 1knot increase in speed, even if it was 2knots it's still a disadvantage imo. But increasing the hull length should help with the boat speed.
Hi Wayne, I definitely see your point and believe me we agonised over this for quiet a bit. I even phoned a few friends lol. The only thing I can say is that our economic speed was 4.2 kts with a clean hull and the world is a big place at that speed. For us we only have a limited amount of time until we run out of money and I have to go back to work full time so we felt it was worth the risk to ensure we reach our goal of going round the world. All we can do is hope that its the right decision but I couldn't look you in the eye and say I am 100% confident that we have done the right thing. Sam
@sailingwiththejamess appreciate your honesty. Understand that speed is important on crossings. At least with aluminium it's easy to put them back if it doesn't work to plan. I'm hoping for you that it doesn't create a problem where the boat slides off swells. I guess time will tell whether it was a smart move or not removing them. I know I couldn't remove them, I'm not that brave.
Sam Crowther has designed them to be towed in as any multihull racing sailor will tell you,water release beween the two foils is the reason not compressing water between the two and basically putting the brakes on,research it mate,love the channel guys
Hey Rex, I looked onto it, consulted a couple of multi hull racers and a naval architect. I don't believe lock designed these skegs. They aren't asymmetrical like foils now we're they slanted inward for lift. I believe there primarily function was to provide protection for the drive train and give us the ability to beach most other things were comprised in order to achieve this. Thank you for the comment I found it absolutely fascinating talking to the multi hull racers. Sam
Not sure you'll gain much through this exercise but hope it works for you. The weight of the skegs would have been negated by the bouyancy provided by the air trapped inside. They probably have approx 50 litres internal capacity so they displace around 50 kilograms of water, more than supporting the weight of the aluminium in their construction. Did you take a lateral measurement across the boat to see if those skegs were parallel? That would be a more important consideration than how each skeg was in relation to it's hull. I doubt the few millimeters of offset would create much drag. Your gain wil come from less wetted surface more than any other thing but you'l lose downwind directional stability. Fairing in those raised welds and having a smooth underwater surface will also increase your performance in light wind. I'd suggest you mark your dagger boards above the deck so you can be sure they're slightly deeper than your props and rudders as a means of protecting the stern gear.
I think you are right with regards to weight. We have been struggling to get the weight off this girl and I may have gotten a bit excited lol. Measuring between the hulls would have been a great idea! I will definitely mark the dagger boards to ensure we protect our rudders as best we can. -sam
@@sailingwiththejamessShorter slimmer & better shaped skeggs that are better aligned with your hulls is probably the best idea those were rather wide & badly shaped with terrible alignment.
Yes I definitely agree with that. I think they went so wide to try and reduce how toed in they would be whilst still encasing the stern tube. We looked into it and we would have to get a naval architect to come look at it and make drawings and them have them fabricated. At this stage we couldn't get a naval architect on such short notice and we don't want to delay our launch date by a month as it would have us finishing close to Christmas and we have already been up here for months. We are ready to get back on the water so we decided to put new skegs on the back burner for a bit (or until we hit our first log lol). -sam
Zoom Zoom. You guys are going to fly with all your tweekings of the hull! Very impressed and cant wait to see what she can do with all your modifications!
Cheers Brad, At this stage we are just working in the underwater side of things. We have big plans for the top sides aswell! It should make a difference, our goal is to have a 7 kt boat after this but only time will tell. Sam
Like a surf board skeg provide directional stability, wait till your surfing down waves in big seas then you'll see why the skegs are there. I know some boats even spinaround with just wind pressure when their skegs are removed.
Cheers, yes I can't agree with you more, when Charlie isn't loving life then we all arnt loving life lol. Great to hear from you and we hope you are travelling well. -sam
Cheers, we hope they will work well. I'll look into the blow up fenders but it will be hard to compete with the price of free Hessian bags that they give out for cyclones or floods lol -sam
Holy moly what a project. I don't know anything about it so I really can't comment but I hope it works out even better than what you are planned. I liked that Kung Fu kick Cait' , Sam Don't want to mess with the wife she can kick a heavy piece of metal like that she could kick your head right off your body. 🤣 Can't wait till your next video My goodness you guys are doing a lot of upgrades to the boat very excited for you both can't wait to see it all. As always stay safe out there and God bless
Hahaha yes I wouldn't want to mess with cait lol. Yeah we are doing as much as we can before we leave Australia as we know the quality of the aluminium here. We always look foward to you kind and encouraging comments. Thank you so much. -sam
I reckon you did the right thing, especially if they were out of whack with each other and towing in does to my thinking not have a good effect going through the water
The belly of the boat and the rudders are both deeper than the props. We will also mark the dagger boards so they will be the deepest point. Hoping not to hit to many rocks 🙏. -sam
Yes it is vonrable but we are swapping our kiwi props for flexofolds which would reduce the chance of damage if we come across submerged objects. We looked into extending the skegs but it would be hard to make them structurally sound and twist then so we don't have them toed in any more. -Sam
That is a courageous move...however with that much 'toe in' it will be really interesting to see what increase in speed you get. I take it your rudders are not designed to take the weight when beached? I used to beach my pescott cat (40' so a lot smaller and lighter than yours) and she'd happily sit on the rudders-- the sand bags is a good idea. Phil
Hi Phil, Unfortunately our rudders aren't designed to take the boats weight. It would be awesome if they could but the bottom of ours are sacrificial and designed to snap on when they (or me) hit something. -sam
@@sailingwiththejamess That is an interesting take on rudders by the builder-- I had mine over built so they wouldn't snap and could take the weight of the boat-- I like the idea of the sandbags, it's so handy being able to beach.
Yes we have seen poeple use sandbags but haven't done it ourselves yet. We look foward to giving it a go. The sacrificial part of the rudders was another thing not part of the design but put on by the previous owner. I do plan to modify the rudders at some point and that feature will not be part of my new design. -sam
I would have liked to have seen the modified skeg built centered and with more depth to still protect the prop and allow careening, the importance of protecting the prop cannot be understated, I d definitely be carrying spare props now you have done that . Also correct me if I m wrong that increasing sugarscoop length will only help with speed if your boat suffered with stern drag ? Our boat does and we have considered lengthening.
Hi Shane, Waterline length helps in many different ways apart from paying for berths or slipping lol. We do bog down in the back end but we are extending primarily to have an easy place to embark and disembark from. Secondly was for buoyancy as we are adding things to our back deck that wernt on the plan so we need to counteract the weight then 3rdly was for increased speed. We have folding props and as there are 2 we are (at this stage) going to risk it. -sam
@@sailingwiththejamesssaw the mod today when we dropped off our little fishing boat for some ally work , looks like solid work you had done , I d still be nervous of accidental running aground and having prop and rudder damage but to be honest you are right you definitely need more speed
@@sailingwiththejamess Was waiting for Ben and saw your boat , had a look and didn't see anyone home so I didn't get to close , will be back in a few days or so to pick up our tow tender , having a heavy duty tow point added , we moved out to Green today as the weather is looking nice for the reef
Oh right I'll look for your tow tender tomorrow. Robin I'd meant to be round this weekend building a table and chairs for us so he should be able to do your tender aswell. Are you on a bigger cat that was up in TI at the end of last yr?
For beaching you might consider suitably sized tyres with lines each side so that they can be adjusted underneath the hull just before drying. They would also serve as heavy grade fenders. Of course the boat’s wingdeck configuration might make line placement and tying off a consideration
I saw in one of the other comments you said your speed was about 4+ knots, for a cat this is terrible , it really should be twice that speed. After you talked about the toe in on the skegs I think the drag would have been huge . I know you have center boards so sideways movement should be minimal when you use those. I wish you the best of luck with the new configuration. Thanks for the video.
Cheers Stephen, I just wish I had thought of measuring across between the 2 to know exactly how far in they were. At a guess measuring the welds they were in about 120mm a side. Can't wait to see the difference when we get launched. -sam
Oh, have not been to the bpat yard for a while, willbegreatto see the progress. We have been putting the tender in at packers camp. Save clogging the yard up with car and trailer.
Hello hello! Have not see you around the yard lately! There's been major headway with all the projects, you will have to see the next time you're in the yard! 🙌 Cait
Like the hessian bag idea. Only issue is that if you unintentionally beach on shingle….as I did when bringing my cat home, it went dark just before I entered home port, all electric gone, including iPad Navigation, was unaware of how far the spit extended. As I understand the line between the lowest part of the hull and the rudder is above the props? And you have very substantial rudders, so you should be ok, though a square of board to place under the rudder would help prevent them sinking into the sand.
Hey Mark! Thank you! We like that Hessian bags won't weigh much, if anything at all, and we can have the option to beach in an emergency. We will miss the protection the skegs gave -Cait
@ I don’t have hessian bags (or polytarp bags, which they now use). But what I do carry is a ‘one ton’ builders bag, we get sand etc delivered in them, non return. I keep it for a make shift sea anchor…might even try it one day
Hi guys you are definitely brave! In your videos you reference the fact that you have some daggerboards somewhere on the boat but you dont say what and where hence my comments are based on an incomplete understanding of your boats configuration. My first observation is that your boat is a heavy old girl! 17 tonnes is a lot of boat to get moving! As a comparison if you look up a Dazcat 1495 which is about the same size as your boat its 5.5 tonnes lightship and 8.5 tonnes fully loaded. The Dazcat is one of the fastest 15 m cruiser racer cats available. Its power to weight ration is at the very top end of the 15m class. Your weight is the biggest influence on your performance! I used to sail a Hobie 14 but I am a few (quite a few) kilos heavier than the guys I raced against. My boat was always much slower than the guys I raced against! Weight is the enemy of catamarans. I was also a rubbish sailor compared to the others hence I was pretty much always last! I'm not sure minor changes to the underwater profile on your boat is going to result in a significant speed change. You have removed 60 kilo of hull weight but also removed some bouyancy hence the change to wetted surface area is probably relatively minor or zero. I cant comment on the level of drag generated by keels that are not quite in line. In engineering terms I suspect the level of drag would depend on whether the water flow over the keels remained "laminar" or whether it was "turbulent" at the back edge of the keels. I am doubtful that turbulent flow would be induced at the sort of speeds you are moving at. Have you worked out how your hull changes (Keels and Sterns) will affect your "centre of lateral resistance"? The "centre of effort" of your boat under sail is normally a few feet behind the mainsail luff. Ideally the "CofLR" should be right below the "CofE". The boat designer will have worked this out to achieve a balanced boat. Chopping bits off and adding bits on may result in your "CofLR" ahead of or aft of your "CofE". If this is the case then to hold a steady course you may need a few degrees of rudder to hold your course which will produce drag and hence slow you down! Not what you want! I wish you luck with your changes and I look forward to hearing about the results. I have spent many years and many £s trying to make my boat go faster. The bottom line is that a clean bottom and reducing weight by dumping some of the rubbish I seem to keep aboard makes the biggest difference. PS I would keep hold of those keels just in case!
Hi Chris, I appreciate your thoughts. We have a crowther #85 mark 4. You do have a point with the centre of lateral resistance. Our boom is 1.5 meters longer than all our sisterships (which don't have skegs). To counteract that we have squared off the sterns to carry the water rail all the way to the end of the sterns. Hopefully this will counter act not having skegs. Once we are launched we will revisit the weight situation but unfortunately we will never be a dazcat. We have 7.5t of aluminium in her but as with us the boat wouldn't hurt if it lost a couple of kgs lol -sam
@@sailingwiththejamess Sam, it sounds like you have given this way more thought than you have let on in the videos! I was shown an interesting way of determining CofLR by Daz of Dazcat when he extended my sterns. (my boat is a 1995 Dazcat...Cloud 9) If you have a decent sized line drawing of your Crowther then make a cardboard cutout of your hull shape below the waterline....add on or take off any alterations then simply work out the balance point of the cutout shape using a thin piece of wood as a fulcrum just like a see saw. That point is approximately your CofLR and you can compare that with where your mast is and your estimated CofE. Trouble is CofE moves around with different headsails and with sail trim so its all a very much a bit of a guess! Good luck with the changes. Your videos are extremely interesting for me as they really take me back to some of the similar changes I made to my boat 20 years ago....I even debated taking my skegs off and replacing them with dagger boards but was persuaded not to. Best wishes Chris
Hi Chris, I just looked up the cloud 9. Did you have the 35 and then extended it to 40, or was it a 40 extended even further. I have been an admirer of dazcats for quite some time now. I absolutely love them. We have all the drawings from the build so I will work out the fulcrum over the next couple of days. -sam
Sam, I have the 35 extended to 40(almost). She is strip plank cedar epoxy glass hulls and foam epoxy glass bridgedeck.There is a launch video somewhere on utube with my younger self and Daz. Interestingly your new keel configuration is very similar to the Dazcat 1495...shortish fixed skegs supporting the prop shaft and daggerboards. Somewhere on the Dazcat/Multi marine website there is a line drawing of the underwater profile for the 1495 which can be beached I think as the skeg is longer and it rocks the boat bow down when beached. Take a look. I am guessing but given that the big keel was never meant to be there on your boat the longer boom and the longer sterns will cancel each other out and you will have a balanced boat. The cardboard exercise might help. Cheers Chris
Chris, I love theorising and I will definitely be doing the cardboard even if it's just for fun. I love that coincidently we have come in line with such awesome boats as the dazcats. We are due for a new set of sails but I am holding off until we are launched in case the boat sint as balanced as what it's supposed to be. -sam
I don't know your boat, but are you positive the weld seam does run down the centreline? Maybe run a string line from bow to stern and then check the skegs. I have built four multis and would not use a seam to check for centreline - use a string line. AS for hessian bags - I am pretty sure this will not work in most situations. Say in Percy Lagoon - the tide sweeps around as it enters and moves the hulls as they settle each tide - so you don't know exactly where you will settle, so the hessian bag idea would not work there. In fact for most of the creeks/lagoons we dry out in, it is hard to know exactly where she will sit and I would not like to have to prop bags under the hulls unless conditions were absolutely perfect. Being able to dry out easily is one of the most wonderful things about cats and I would give up performance to ensure we can do this. Because you don't seen to have used string lines to line up the skegs, I am not sure they are off centre and the drag reduction may not be significant. AS for one extra knot - put me down as a no. It is your boat - but I reckon the kids will miss being able to have a boat that can't go into Hill inlet, Leekes Creek, Percy lagoon, Zoe North and all the other spots we have dried out in. I wouldn't trade a speed incease of a knot and loise that
We have a 10mm keel plate running the length of the vessel marking the centre line. The design of the boat is a classic crowther so if you imagine normal hulls then kick them out 8 degrees. This makes our centre line off the actual centre, our engines are in the actual centre horizontal (not at 8 degrees) which has caused the problem. The boat was designed with sail drives and was modified at build for inboards. This is what has caused the problems, we will definitely miss all the places that you have listed and hope to not test the strength of the rudders. I will keep you posted on what the speed ends up being. -sam
@@sailingwiththejamess Ah yes, the Crowther flare. This will change things in a strange way - I hadn't thought of that. Maybe you can work out a better skeg that is aligned with the water flow. Maybe put a GoPro under the water with some telltales on the bottom and you can find the flow and make a small skeg so you can take the bottom again. I would hate to have a tough cat that can't take the ground.
Hi Frank, yes I definitely think so. We would idle along at 1200 rpm to do 4.2 kts and if we brought the engines up to peak torque which is 1800 rpm we would only come up to about 5.8 to 6 kts but our fuel consumption would over double. There are dogs in the yard to keep the snakes and vermin away but they haven't made friends with Frank yet so he stays on the boat for the most part and we just take him for walks every now and again. -sam
It will be interesting to see how much difference you see. I would guess it would make a noticeable difference especially with the toe in you measured. Have you measured the hull centre line to check to see if they are parallel?
No I didn't measure and wish I had. You could see with the naked eye that they weren't and for intrests sake I went down there and measured across where the weld marks were And found that there was a 235 mm difference. I know this is a terrible and inaccurate way of doing it and I should have done it with the skegs on but I couldn't help but have a look. -sam
Well I have had to re-visit your post. I went to bed for a Nanna Knapp, but had to get up and make a comment. I think you have done reprehensible damage to you boat. In an engineering manner it is best If I explain my issue with the removal of your skeggs. An easy explanation is by using say a knife. Hols this knife horizontal in the water and slide it side ways. Is is easy. Now turn that knife vertical and try it, it is going to be harder. Now using a meat cleaver and so the same and you get a far greater resistance through the water. You on the other hand have taken away stability in sideways and forward motion. You will need to increase the size of your rudders to give you a lot more control you have lost. Gaining a knot in speed at the loss of control is detrimental. You are going to slide sideways when in motion for 1. 2 you are losing forward direction by about 45% so you are putting more pressure on the rudder system. My family have built river paddle boats for years and these boats draw only 12 to 18" in depth. This we notice that when it is a windy day we are blown all over the place. Forward motion with the flat bottom you travel almost twice the distance as there is no forward stability. So with you removal of the skeggs you are going to fall into the same problem, and that 1 knot you saved you are going to travel further negating this knot of speed. Just my opinion and sorry about the rant.
All options are welcome my friend and don't be sorry about the rant. I love passionate people especially when it comes to boats because it is my passion also. One thing to bear in mind is that we have dagger boards. Granted that we hardly used them when we had skeds but we do have the ability to achieve lateral resistance. As the dagger boards are slot further away from the rudders giving us far greater turning moments we are hoping for better steering. We understand that we may have to modify our daggerboards for better efficiency. At this stage we will not be increasing the size of the rudders ut I am open to in down the track if need be. -sam
Agreed with sam. Was a bit horrified. But if you have daggerboards then thats not so bad. It does seem shame to leave props exposed to nets/strikes more so but guess your prepared to live with that. Kates video editing is getting good! All the best team👍
Cheers, hoping to be lucky with regards to prop strikes and Kate's editing is getting real good. We have learnt a lot over the last couple of years. Thank you so much for noticing. -sam
Hi Sam Cait Charlie, U do know Emma is a big boat, heavy anyway, I'm not real sure that was a good idea at all, even to gain 3knts. Filling heshan sacks with sand will be a pain, try dragging a heavy sand bag, no thanks, she's ur boat goodluck. Much love xx what's going to protect the rudders now?
Thank you, hence the big debate in the yard! We agonised over this for a long time and made the decision to cut them off. We are excited to get her splashed and see what she can do! -Cait
Haha I truly hope I am wrong but I do believe that s vandalism, I cant believe you will be able to get insurance now? Massively comprimised the stability and safety of the boat but Ido wish you the very best
I dont understand, you either need mini keels or daggerboards, otherwise the leeway will totally offset any other advantages, Changes like this need to be be assessed by marine engineers, its not a thing for amateurs to play with. If the boat was not built to design in terms of the mini keels, then that would need to be rectified, but just removing them is a dangerous option IMO. I would definitely recommend getting some professional advice.
I completely agree you definitely need daggerboards or mini keels. We have daggerboards as per the design, what we cut off were the skegs. The skegs were not part of the design but were added on in the build process. They gave us the wonderful ability to beach and added great protection to our running gear which we will miss. -sam
@@sailingwiththejamess LOL! Totally missed that you had daggerboards, despite watching every episode!! Now I get it. Lots of cats with daggerboards are able to be beached, I guess the complication for you is shaft drives and rudders that cant be swung up. Shaftdrives and props probably fine with the skegs, but rudders would be problematic.
Lol no worries you definitely arent the only one. I think we need to work on our explanations. Yes rudders would definitely be problematic. The last time we beached we busted our paddle wheel (speed log) aswell so at this stage we don't plan to Bach any more and will be putting an ablative anti fowl on. -sam
@@sailingwiththejamess Its definitely handy to be able to beach, we do it every 3 months or so and scrape our hulls, we use an ablative anti-foul (Micron 1), but it still needs a scrape regularly, I guess if we were sailing full time it would help, but thats not our reality.
Beaching ability is always handy, the hessan bags should do the trick if we ever need. Have heard good thing of Micron 1, we currently have Pettit Vivid on, hull prep and anti fouling days are fast approaching as relaunch is soon! -Cait
Hey Jo, Yes it would have been better but I didn't want to mess with our engine alignment. We have found all these things that we want to change but they weren't in the initial budget so we are improving them and doing what we can whilst keeping the costs down. We figure doing something is better than doing nothing at all. -sam
hello: If you have other gone too far along I Wish I can talk you you about SCACCOARDS INSTEAD OF daggerboards.......It is tbe SAFEST design you can pla e instead of daggerboards and have the SAFETY of centerboards
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Hey - what a bold move.
We had dagger boards on our crowther and replaced them with fixed "minikeels". Our cat was already extended to 54 ft with sugar scoops. In the process we moved the keels more towards the stern as our cat had a tendency to turn into wind (weather helm). The surface area/wet area was kept about the same as it was with the daggerboards. Keels were moved closer to the stern and now we enjoy much better performance. Plus easier to sail as one does not have to work the daggerboards...interesting to see how this will affect on your upwind performance. Maybe one knot increase is on conservative side going downwind.
All the best and please keep making these videos!
Arto
Sailing Catamaran Paws
Arto! Great to hear from you! Hope the hawksberry is treating you well. It was a bold move and we are excited to see if it all pans out the way we hope. Mini keels would make things easier, wow so you have 4 ft extensions! Hope to see you out there.
Sam
Hi Sam. Well done for cutting off the water brakes. I had to read all your comments to find that they were an addition to the original design and therefore cutting them off has no structural impact on the integrity of your boat. I could not understand why you had dagger boards and skegs as cats are designed with one or the other. Belt and braces as my bridging design engineers would call it. 😂
Hahaha cheers for the positive feed back. The proof will be when we get re launched. Fingers crossed it does all we hope it will
-sam
Totally agree with what you've done. The sheer thickness of those skegs is enough to scare the speed gods away lol. But if they weren't parallel then it's like driving with a hand brake on.
The weight will make a slight difference but then again 60kg is just one extra pretty girl and I'm sure that's gonna happen haha so let's forget about the weight saving.
You'll save loads on drag, draw less which is a real bonus and go faster toboot, win win all round.
You have your welder guy there, have him check the structure/support at the low parts of the hulls, they would have originally been strengthened to take the boats weight via the skegs, I'd be surprised if you couldn't beach the boat as it is, you may need a folding prop if your prop blades are the lowest part of the hull .
But well done for even looking for and finding the issue, I doubt many people would even do that and then to fix it.... Well in my book your daily dairy just got a gold star ⭐
Cheers guys 🍻
Hahaha love your answer. I must say I already have 2 pretty girls on board which is enough for me lol. Surprisingly they didn't add any extra supports but it may be because we are aluminium and strong enough lol. Thanks again for your comment it has made my morning.
-sam
Yep I was one that questioned the removal of the skegs last week, and I'm still questioning it this week. Your boat, your choice. But I see a lot of disadvantages for a 1knot increase in speed, even if it was 2knots it's still a disadvantage imo. But increasing the hull length should help with the boat speed.
Hi Wayne,
I definitely see your point and believe me we agonised over this for quiet a bit. I even phoned a few friends lol. The only thing I can say is that our economic speed was 4.2 kts with a clean hull and the world is a big place at that speed. For us we only have a limited amount of time until we run out of money and I have to go back to work full time so we felt it was worth the risk to ensure we reach our goal of going round the world. All we can do is hope that its the right decision but I couldn't look you in the eye and say I am 100% confident that we have done the right thing.
Sam
@sailingwiththejamess appreciate your honesty. Understand that speed is important on crossings. At least with aluminium it's easy to put them back if it doesn't work to plan. I'm hoping for you that it doesn't create a problem where the boat slides off swells. I guess time will tell whether it was a smart move or not removing them. I know I couldn't remove them, I'm not that brave.
I will keep everyone posted as to the improvements and hope that Lady luck looks after our rudders.
-sam
Sam Crowther has designed them to be towed in as any multihull racing sailor will tell you,water release beween the two foils is the reason not compressing water between the two and basically putting the brakes on,research it mate,love the channel guys
Hey Rex, I looked onto it, consulted a couple of multi hull racers and a naval architect. I don't believe lock designed these skegs. They aren't asymmetrical like foils now we're they slanted inward for lift. I believe there primarily function was to provide protection for the drive train and give us the ability to beach most other things were comprised in order to achieve this. Thank you for the comment I found it absolutely fascinating talking to the multi hull racers.
Sam
Not sure you'll gain much through this exercise but hope it works for you. The weight of the skegs would have been negated by the bouyancy provided by the air trapped inside. They probably have approx 50 litres internal capacity so they displace around 50 kilograms of water, more than supporting the weight of the aluminium in their construction.
Did you take a lateral measurement across the boat to see if those skegs were parallel? That would be a more important consideration than how each skeg was in relation to it's hull. I doubt the few millimeters of offset would create much drag.
Your gain wil come from less wetted surface more than any other thing but you'l lose downwind directional stability. Fairing in those raised welds and having a smooth underwater surface will also increase your performance in light wind.
I'd suggest you mark your dagger boards above the deck so you can be sure they're slightly deeper than your props and rudders as a means of protecting the stern gear.
I think you are right with regards to weight. We have been struggling to get the weight off this girl and I may have gotten a bit excited lol. Measuring between the hulls would have been a great idea! I will definitely mark the dagger boards to ensure we protect our rudders as best we can.
-sam
@@sailingwiththejamessShorter slimmer & better shaped skeggs that are better aligned with your hulls is probably the best idea those were rather wide & badly shaped with terrible alignment.
Yes I definitely agree with that. I think they went so wide to try and reduce how toed in they would be whilst still encasing the stern tube. We looked into it and we would have to get a naval architect to come look at it and make drawings and them have them fabricated. At this stage we couldn't get a naval architect on such short notice and we don't want to delay our launch date by a month as it would have us finishing close to Christmas and we have already been up here for months. We are ready to get back on the water so we decided to put new skegs on the back burner for a bit (or until we hit our first log lol).
-sam
Zoom Zoom. You guys are going to fly with all your tweekings of the hull! Very impressed and cant wait to see what she can do with all your modifications!
Cheers Brad,
At this stage we are just working in the underwater side of things. We have big plans for the top sides aswell! It should make a difference, our goal is to have a 7 kt boat after this but only time will tell.
Sam
Like a surf board skeg provide directional stability, wait till your surfing down waves in big seas then you'll see why the skegs are there. I know some boats even spinaround with just wind pressure when their skegs are removed.
Ahh yes you are right and like surf boards they were toed in. The difference is they are toed in on a surf board to loosen up the back end.
-sam
Chop chop! Sometimes an extra 1 knot over even a short passage can make the difference between a very unhappy toddler and a happy one! Great work! 👏
Cheers, yes I can't agree with you more, when Charlie isn't loving life then we all arnt loving life lol. Great to hear from you and we hope you are travelling well.
-sam
Hessian bags are a great idea, those blow up fenders would be great too, not sure how expensive they are. Enjoying your repairs.
Cheers, we hope they will work well.
I'll look into the blow up fenders but it will be hard to compete with the price of free Hessian bags that they give out for cyclones or floods lol
-sam
Interesting, cheers guys!
Thank you Trev, youre a legend mate!
Bloody impresive mate looking forward to the results
THANK YOU MAL! We are looking forward to getting her in the water and seeing what she can do!
-Cait
Holy moly what a project. I don't know anything about it so I really can't comment but I hope it works out even better than what you are planned. I liked that Kung Fu kick Cait' , Sam Don't want to mess with the wife she can kick a heavy piece of metal like that she could kick your head right off your body. 🤣 Can't wait till your next video My goodness you guys are doing a lot of upgrades to the boat very excited for you both can't wait to see it all. As always stay safe out there and God bless
Hahaha yes I wouldn't want to mess with cait lol. Yeah we are doing as much as we can before we leave Australia as we know the quality of the aluminium here. We always look foward to you kind and encouraging comments. Thank you so much.
-sam
I reckon you did the right thing, especially if they were out of whack with each other and towing in does to my thinking not have a good effect going through the water
Cheers! We are confident that we have done the right thing and I just over a week we will know for sure when we get launched!
-sam
Is there anything to protect the prop blades from hitting rocks or sitting on the blades if a low tide?
The belly of the boat and the rudders are both deeper than the props. We will also mark the dagger boards so they will be the deepest point. Hoping not to hit to many rocks 🙏.
-sam
I probably would have gone for 'Shortening' the skeggs , Possibly new more slippery shape ,That prop looks awfully vulnerable now. ?
Yes it is vonrable but we are swapping our kiwi props for flexofolds which would reduce the chance of damage if we come across submerged objects. We looked into extending the skegs but it would be hard to make them structurally sound and twist then so we don't have them toed in any more.
-Sam
That is a courageous move...however with that much 'toe in' it will be really interesting to see what increase in speed you get. I take it your rudders are not designed to take the weight when beached? I used to beach my pescott cat (40' so a lot smaller and lighter than yours) and she'd happily sit on the rudders-- the sand bags is a good idea. Phil
Hi Phil,
Unfortunately our rudders aren't designed to take the boats weight. It would be awesome if they could but the bottom of ours are sacrificial and designed to snap on when they (or me) hit something.
-sam
@@sailingwiththejamess That is an interesting take on rudders by the builder-- I had mine over built so they wouldn't snap and could take the weight of the boat-- I like the idea of the sandbags, it's so handy being able to beach.
Yes we have seen poeple use sandbags but haven't done it ourselves yet. We look foward to giving it a go. The sacrificial part of the rudders was another thing not part of the design but put on by the previous owner. I do plan to modify the rudders at some point and that feature will not be part of my new design.
-sam
I would have liked to have seen the modified skeg built centered and with more depth to still protect the prop and allow careening, the importance of protecting the prop cannot be understated, I d definitely be carrying spare props now you have done that .
Also correct me if I m wrong that increasing sugarscoop length will only help with speed if your boat suffered with stern drag ? Our boat does and we have considered lengthening.
Hi Shane,
Waterline length helps in many different ways apart from paying for berths or slipping lol. We do bog down in the back end but we are extending primarily to have an easy place to embark and disembark from. Secondly was for buoyancy as we are adding things to our back deck that wernt on the plan so we need to counteract the weight then 3rdly was for increased speed.
We have folding props and as there are 2 we are (at this stage) going to risk it.
-sam
@@sailingwiththejamesssaw the mod today when we dropped off our little fishing boat for some ally work , looks like solid work you had done , I d still be nervous of accidental running aground and having prop and rudder damage but to be honest you are right you definitely need more speed
Speed is always good. Its easy to slow a boat down but sometimes hard to speed them up. We were in the yard all day today I must have missed you!
-sam
@@sailingwiththejamess Was waiting for Ben and saw your boat , had a look and didn't see anyone home so I didn't get to close , will be back in a few days or so to pick up our tow tender , having a heavy duty tow point added , we moved out to Green today as the weather is looking nice for the reef
Oh right I'll look for your tow tender tomorrow. Robin I'd meant to be round this weekend building a table and chairs for us so he should be able to do your tender aswell. Are you on a bigger cat that was up in TI at the end of last yr?
WOW! Nerves of Steel
Thank you!
@@sailingwiththejamessAl actually …
I may be a bit of an old man but what does Al mean?
-sam
Wait wait I think I got it. Aluminium actually lol. Wow I am An old man lol
-sam
@@sailingwiththejamess aluminium
For beaching you might consider suitably sized tyres with lines each side so that they can be adjusted underneath the hull just before drying. They would also serve as heavy grade fenders. Of course the boat’s wingdeck configuration might make line placement and tying off a consideration
Tyers would work. We just like the Hessian bags because they are free, don't take up much space and don't weigh much.
-sam
The added wieght in tyres will balance the wieght saving of the skegs
Yes it would but cait has already used up that weight allocation lol.
-sam
I saw in one of the other comments you said your speed was about 4+ knots, for a cat this is terrible , it really should be twice that speed. After you talked about the toe in on the skegs I think the drag would have been huge . I know you have center boards so sideways movement should be minimal when you use those. I wish you the best of luck with the new configuration. Thanks for the video.
Cheers Stephen,
I just wish I had thought of measuring across between the 2 to know exactly how far in they were.
At a guess measuring the welds they were in about 120mm a side.
Can't wait to see the difference when we get launched.
-sam
Oh, have not been to the bpat yard for a while, willbegreatto see the progress. We have been putting the tender in at packers camp. Save clogging the yard up with car and trailer.
Hello hello! Have not see you around the yard lately! There's been major headway with all the projects, you will have to see the next time you're in the yard! 🙌
Cait
Like the hessian bag idea.
Only issue is that if you unintentionally beach on shingle….as I did when bringing my cat home, it went dark just before I entered home port, all electric gone, including iPad Navigation, was unaware of how far the spit extended.
As I understand the line between the lowest part of the hull and the rudder is above the props? And you have very substantial rudders, so you should be ok, though a square of board to place under the rudder would help prevent them sinking into the sand.
Hey Mark! Thank you!
We like that Hessian bags won't weigh much, if anything at all, and we can have the option to beach in an emergency. We will miss the protection the skegs gave
-Cait
@ I don’t have hessian bags (or polytarp bags, which they now use).
But what I do carry is a ‘one ton’ builders bag, we get sand etc delivered in them, non return. I keep it for a make shift sea anchor…might even try it one day
Will do some research on them, thanks!
-Cait
Hi guys you are definitely brave!
In your videos you reference the fact that you have some daggerboards somewhere on the boat but you dont say what and where hence my comments are based on an incomplete understanding of your boats configuration.
My first observation is that your boat is a heavy old girl! 17 tonnes is a lot of boat to get moving! As a comparison if you look up a Dazcat 1495 which is about the same size as your boat its 5.5 tonnes lightship and 8.5 tonnes fully loaded. The Dazcat is one of the fastest 15 m cruiser racer cats available. Its power to weight ration is at the very top end of the 15m class. Your weight is the biggest influence on your performance! I used to sail a Hobie 14 but I am a few (quite a few) kilos heavier than the guys I raced against. My boat was always much slower than the guys I raced against! Weight is the enemy of catamarans. I was also a rubbish sailor compared to the others hence I was pretty much always last!
I'm not sure minor changes to the underwater profile on your boat is going to result in a significant speed change. You have removed 60 kilo of hull weight but also removed some bouyancy hence the change to wetted surface area is probably relatively minor or zero.
I cant comment on the level of drag generated by keels that are not quite in line. In engineering terms I suspect the level of drag would depend on whether the water flow over the keels remained "laminar" or whether it was "turbulent" at the back edge of the keels. I am doubtful that turbulent flow would be induced at the sort of speeds you are moving at.
Have you worked out how your hull changes (Keels and Sterns) will affect your "centre of lateral resistance"? The "centre of effort" of your boat under sail is normally a few feet behind the mainsail luff. Ideally the "CofLR" should be right below the "CofE". The boat designer will have worked this out to achieve a balanced boat. Chopping bits off and adding bits on may result in your "CofLR" ahead of or aft of your "CofE". If this is the case then to hold a steady course you may need a few degrees of rudder to hold your course which will produce drag and hence slow you down! Not what you want!
I wish you luck with your changes and I look forward to hearing about the results. I have spent many years and many £s trying to make my boat go faster. The bottom line is that a clean bottom and reducing weight by dumping some of the rubbish I seem to keep aboard makes the biggest difference.
PS I would keep hold of those keels just in case!
Hi Chris,
I appreciate your thoughts. We have a crowther #85 mark 4. You do have a point with the centre of lateral resistance. Our boom is 1.5 meters longer than all our sisterships (which don't have skegs). To counteract that we have squared off the sterns to carry the water rail all the way to the end of the sterns. Hopefully this will counter act not having skegs. Once we are launched we will revisit the weight situation but unfortunately we will never be a dazcat. We have 7.5t of aluminium in her but as with us the boat wouldn't hurt if it lost a couple of kgs lol
-sam
@@sailingwiththejamess
Sam, it sounds like you have given this way more thought than you have let on in the videos! I was shown an interesting way of determining CofLR by Daz of Dazcat when he extended my sterns. (my boat is a 1995 Dazcat...Cloud 9) If you have a decent sized line drawing of your Crowther then make a cardboard cutout of your hull shape below the waterline....add on or take off any alterations then simply work out the balance point of the cutout shape using a thin piece of wood as a fulcrum just like a see saw. That point is approximately your CofLR and you can compare that with where your mast is and your estimated CofE. Trouble is CofE moves around with different headsails and with sail trim so its all a very much a bit of a guess!
Good luck with the changes. Your videos are extremely interesting for me as they really take me back to some of the similar changes I made to my boat 20 years ago....I even debated taking my skegs off and replacing them with dagger boards but was persuaded not to.
Best wishes
Chris
Hi Chris,
I just looked up the cloud 9. Did you have the 35 and then extended it to 40, or was it a 40 extended even further. I have been an admirer of dazcats for quite some time now. I absolutely love them. We have all the drawings from the build so I will work out the fulcrum over the next couple of days.
-sam
Sam, I have the 35 extended to 40(almost). She is strip plank cedar epoxy glass hulls and foam epoxy glass bridgedeck.There is a launch video somewhere on utube with my younger self and Daz. Interestingly your new keel configuration is very similar to the Dazcat 1495...shortish fixed skegs supporting the prop shaft and daggerboards. Somewhere on the Dazcat/Multi marine website there is a line drawing of the underwater profile for the 1495 which can be beached I think as the skeg is longer and it rocks the boat bow down when beached. Take a look.
I am guessing but given that the big keel was never meant to be there on your boat the longer boom and the longer sterns will cancel each other out and you will have a balanced boat. The cardboard exercise might help.
Cheers
Chris
Chris, I love theorising and I will definitely be doing the cardboard even if it's just for fun. I love that coincidently we have come in line with such awesome boats as the dazcats. We are due for a new set of sails but I am holding off until we are launched in case the boat sint as balanced as what it's supposed to be.
-sam
I don't know your boat, but are you positive the weld seam does run down the centreline? Maybe run a string line from bow to stern and then check the skegs. I have built four multis and would not use a seam to check for centreline - use a string line.
AS for hessian bags - I am pretty sure this will not work in most situations. Say in Percy Lagoon - the tide sweeps around as it enters and moves the hulls as they settle each tide - so you don't know exactly where you will settle, so the hessian bag idea would not work there. In fact for most of the creeks/lagoons we dry out in, it is hard to know exactly where she will sit and I would not like to have to prop bags under the hulls unless conditions were absolutely perfect. Being able to dry out easily is one of the most wonderful things about cats and I would give up performance to ensure we can do this.
Because you don't seen to have used string lines to line up the skegs, I am not sure they are off centre and the drag reduction may not be significant. AS for one extra knot - put me down as a no. It is your boat - but I reckon the kids will miss being able to have a boat that can't go into Hill inlet, Leekes Creek, Percy lagoon, Zoe North and all the other spots we have dried out in. I wouldn't trade a speed incease of a knot and loise that
We have a 10mm keel plate running the length of the vessel marking the centre line. The design of the boat is a classic crowther so if you imagine normal hulls then kick them out 8 degrees. This makes our centre line off the actual centre, our engines are in the actual centre horizontal (not at 8 degrees) which has caused the problem. The boat was designed with sail drives and was modified at build for inboards. This is what has caused the problems, we will definitely miss all the places that you have listed and hope to not test the strength of the rudders. I will keep you posted on what the speed ends up being.
-sam
@@sailingwiththejamess Ah yes, the Crowther flare. This will change things in a strange way - I hadn't thought of that. Maybe you can work out a better skeg that is aligned with the water flow. Maybe put a GoPro under the water with some telltales on the bottom and you can find the flow and make a small skeg so you can take the bottom again. I would hate to have a tough cat that can't take the ground.
Yes I gree. It is a bummer having a tough cat that we can't beach. I like to gopro idea.
-sam
The engine will be happy that it doesn't have to work so hard. Looks like Frank knows which boat is home.
Hi Frank, yes I definitely think so. We would idle along at 1200 rpm to do 4.2 kts and if we brought the engines up to peak torque which is 1800 rpm we would only come up to about 5.8 to 6 kts but our fuel consumption would over double.
There are dogs in the yard to keep the snakes and vermin away but they haven't made friends with Frank yet so he stays on the boat for the most part and we just take him for walks every now and again.
-sam
@@sailingwiththejamess lol Frank would give them a hand.
Haha i bet he would love to but I don't know how impressed cait and Charlie would be if he brought his conquests back to the boat lol.
-sam
It will be interesting to see how much difference you see. I would guess it would make a noticeable difference especially with the toe in you measured. Have you measured the hull centre line to check to see if they are parallel?
No I didn't measure and wish I had. You could see with the naked eye that they weren't and for intrests sake I went down there and measured across where the weld marks were And found that there was a 235 mm difference. I know this is a terrible and inaccurate way of doing it and I should have done it with the skegs on but I couldn't help but have a look.
-sam
where are you? first time here, all the best
Hi Allan, we are currently in cairns qld Australia but all going well we will be heading down south in a couple of weeks to get put of the heat.
-sam
Emma James will be amazing. 1 knot? Go you good thing.
Thank you!! We will find out shortly when we are relaunched how much of a difference they have made!
-Cait
❤❤
Cheers.
-sam
Well I have had to re-visit your post. I went to bed for a Nanna Knapp, but had to get up and make a comment. I think you have done reprehensible damage to you boat. In an engineering manner it is best If I explain my issue with the removal of your skeggs. An easy explanation is by using say a knife. Hols this knife horizontal in the water and slide it side ways. Is is easy. Now turn that knife vertical and try it, it is going to be harder. Now using a meat cleaver and so the same and you get a far greater resistance through the water. You on the other hand have taken away stability in sideways and forward motion. You will need to increase the size of your rudders to give you a lot more control you have lost. Gaining a knot in speed at the loss of control is detrimental. You are going to slide sideways when in motion for 1. 2 you are losing forward direction by about 45% so you are putting more pressure on the rudder system. My family have built river paddle boats for years and these boats draw only 12 to 18" in depth. This we notice that when it is a windy day we are blown all over the place. Forward motion with the flat bottom you travel almost twice the distance as there is no forward stability. So with you removal of the skeggs you are going to fall into the same problem, and that 1 knot you saved you are going to travel further negating this knot of speed. Just my opinion and sorry about the rant.
All options are welcome my friend and don't be sorry about the rant. I love passionate people especially when it comes to boats because it is my passion also. One thing to bear in mind is that we have dagger boards. Granted that we hardly used them when we had skeds but we do have the ability to achieve lateral resistance. As the dagger boards are slot further away from the rudders giving us far greater turning moments we are hoping for better steering. We understand that we may have to modify our daggerboards for better efficiency. At this stage we will not be increasing the size of the rudders ut I am open to in down the track if need be.
-sam
Agreed with sam. Was a bit horrified. But if you have daggerboards then thats not so bad. It does seem shame to leave props exposed to nets/strikes more so but guess your prepared to live with that. Kates video editing is getting good! All the best team👍
Cheers, hoping to be lucky with regards to prop strikes and Kate's editing is getting real good. We have learnt a lot over the last couple of years. Thank you so much for noticing.
-sam
Sad to loose the ability to beach. . .
Yes very sad. Especially for those unplanned beachings that we all experience from time to time.
-sam
You'll definitely be faster. Having the brakes on all the time would be very annoying
Cheers Mr sensible! I agree it was annoying.
-sam
Hi Sam Cait Charlie, U do know Emma is a big boat, heavy anyway, I'm not real sure that was a good idea at all, even to gain 3knts. Filling heshan sacks with sand will be a pain, try dragging a heavy sand bag, no thanks, she's ur boat goodluck. Much love xx what's going to protect the rudders now?
Thank you, hence the big debate in the yard! We agonised over this for a long time and made the decision to cut them off. We are excited to get her splashed and see what she can do!
-Cait
@@sailingwiththejamess awesome, I know it will be fine, just want the best 4 u all xxx
Thanks for your kind thoughts.
-sam
Haha I truly hope I am wrong but I do believe that s vandalism, I cant believe you will be able to get insurance now? Massively comprimised the stability and safety of the boat but Ido wish you the very best
Hey Jeremy, as the skegs are not part of the vessels plans but additional add ons done at the initial build it won't affect insurance at all.
-sam
I dont understand, you either need mini keels or daggerboards, otherwise the leeway will totally offset any other advantages, Changes like this need to be be assessed by marine engineers, its not a thing for amateurs to play with. If the boat was not built to design in terms of the mini keels, then that would need to be rectified, but just removing them is a dangerous option IMO. I would definitely recommend getting some professional advice.
I completely agree you definitely need daggerboards or mini keels. We have daggerboards as per the design, what we cut off were the skegs. The skegs were not part of the design but were added on in the build process. They gave us the wonderful ability to beach and added great protection to our running gear which we will miss.
-sam
@@sailingwiththejamess LOL! Totally missed that you had daggerboards, despite watching every episode!! Now I get it. Lots of cats with daggerboards are able to be beached, I guess the complication for you is shaft drives and rudders that cant be swung up. Shaftdrives and props probably fine with the skegs, but rudders would be problematic.
Lol no worries you definitely arent the only one. I think we need to work on our explanations. Yes rudders would definitely be problematic. The last time we beached we busted our paddle wheel (speed log) aswell so at this stage we don't plan to Bach any more and will be putting an ablative anti fowl on.
-sam
@@sailingwiththejamess Its definitely handy to be able to beach, we do it every 3 months or so and scrape our hulls, we use an ablative anti-foul (Micron 1), but it still needs a scrape regularly, I guess if we were sailing full time it would help, but thats not our reality.
Beaching ability is always handy, the hessan bags should do the trick if we ever need. Have heard good thing of Micron 1, we currently have Pettit Vivid on, hull prep and anti fouling days are fast approaching as relaunch is soon!
-Cait
If they were still toed in wouldn't it be better to put p bracket in and get rid of the sides all together?
Hey Jo,
Yes it would have been better but I didn't want to mess with our engine alignment. We have found all these things that we want to change but they weren't in the initial budget so we are improving them and doing what we can whilst keeping the costs down. We figure doing something is better than doing nothing at all.
-sam
hello: If you have other gone too far along I Wish I can talk you you about SCACCOARDS INSTEAD OF daggerboards.......It is tbe SAFEST design you can pla e instead of daggerboards and have the SAFETY of centerboards
Hey Norman, I appreciate the comment! You are about 20 years too late, she was designed and built with daggerboards 😊
-Cait
Maybe carry a spare prop.
We have new props, very excited, stay tuned!
We have new props, very excited, stay tuned!