Thank you! We are happy to learn that Axel's ideas and our project sparked so much interest and curiosity! We hope we turn it into a successful project! Thanks for commenting and a simple "like" and "share" go a long way! Hope to see you next Sunday!
the definition of Ducted props actually sets it as somewhat sensible within the sailing vessel realm. the problem is the drag when not in use, However, that could be overcome by making it Also re-gen system.....prop re-gen can generate quite a bit of power, but many systems produce pathetic amounts of power because they don't include dedicated circuitry to handle the battery charging.....where with dedicated charging circuitry, prop re-gen could make more power than a deck full of solar panels ..... but the duct needs to be a revolved air foil for efficientcy, and airfoil duct design is complicated, being contingent on many parameters.
@@buildingwilda or to say, I would cut those PVC ducts as short as practically possible, and try to emulate an airfoil shape in the edge treatments. and build dedicated battery charging circuits.
We will not be able to create an efficient foil in the duct. Perhaps something we can work with in the future. The drag will be a non issue as the drive is retractable. We don't have dedicated charging circuitry, but the controller is designed for regenerative breaking and this setting can be tuned to optimise regen. The type of prop should lend itself nicely to regen .. I hope. And should be able to generate power at a much lower boat speed than other systems I've seen. Large surface area, low pitch... Should generate higher rpm earlier, leading to increased regen efficiency. We'll see how efficient... The drawback is speed under engine, but it's a sailboat ⛵ Thanks for the comments! Hope you stick around as we get it all together and into the water 🌊
@@buildingwilda Oh , Sorry, i didn't realize they were going to be made retractable... the Sevcons don't regen so well....but it helps to dig into the programming and get what you can out of it....regen braking, on a wheeled vehicle, wants to push against battery voltage....where prop Regen, you want rectification into a large low voltage capacitor bank, and a switching boost regulator, to boost to charge from there.
This is cool, its been around for a while like you said. My favorite version used rim drives because they can pass ropes and other items through without fowling. The other versions also added and upper cap to keep the cavity protected, I also thing it kept to much seawater from being trapped inside the tube. You might want to add a way to remove any trapped seawater from the tube. If you want to be environmentally aware you can turn the propeller into a sort of a self washing machine by pumping some fresh water into the propeller tube. The fresh water is a hostile environment for the sea life that wants to attach to your equipment. I am not sure how much fresh water to add but I don't think it would take to much. The not so environmentally nice way it to build a pocket in the tube for a bleach puck or some other method of injecting the water in the cavity with a cleaner, biodegradable soap is an option, but I'm not sure how much of a hostile environment it would create, and if you turn on the propellers well.... have you ever seen what happens in a washing machine and dish soap. You would leave a trail of bubbles as you sailed away. 13 hp motors seem pretty small fort the size of boat, but if you are okay with it I say go. I would recommend a 25 hp outboard or larger on your dingy and a mod on the back of the boat to allow for use on the full size boat in an emergency. That way you have a double duty backup. It's a very cool concept, and I have only seen this on super yachts so this should be interesting to see how you solve your issues as they come up. Good Luck! -MG
Very close to our thinking. A 25 hp dinghy outboard would be great. We'll see when we get there. Planning on a 3m is tender, so may be limited to a little less power. As for the fouling in the cylinders... I'm hoping the lack of sunlight will keep growth down and almost all of the prop will be above the waterline when retracted. Rim drives are super cool. Just not an economically viable option. Nor are any other retractable options. Even fixed commercially available options are extremely pricey... I think we'll get it working well. How well, remains to be seen.
This is an exciting project. However I don’t understand the gross negativity people have with your adventure - are they just trying to troll you. If they don’t like what you are doing - don’t watch. I am both intrigued and admire your efforts. Congratulations on attempting something different - from what I have seen so far, it’s going to be a grand adventure.
Thank you! Appreciate your constructive feedback and we try to keep our eyes and ears open to feedback in general! However, we don't want to take to heart the not so positive comments :) It is indeed a fantastic adventure and it's taking much longer than we would have ever thought. But now we're in it and we "have to dance to the music" :) Thanks again! Hope to see you next Sunday!
My first reaction is: not another electric catamaran. Electricity is the worst thing in a sailboat. You can expect to have to replace all your electronics every few years (corrosion) if you don't get a lightning strike, then it's right away. I have been in the bahamas in a tiny catamaran with two outboard (one for the boat, another for the dighy) and we had to use the one of the dighny multible times to get out of trouble. I have seen many with luxury and complicated stuff break and people fall back on their dream of crusing because of tech that was broken. Sailing is more about duck tape and mcgiver than any other thing I know. If their dream is to build electronic stuff and fix it good, if their dream is to sail then this is *very* costly distraction. I recommend reading: champagne cruising on a beer budget and looking at this channel: www.youtube.com/@samholmessailing to see how you can go sailing on great adventure on a tiny budget. At the end, sailing is about the sea, the weather and the places you go way more than the boat. Still a big fan of EV, Tesla, etc, just not on a boat (for now)
Fantastic Axel and Rox , Cant wait for more of this electric propulsion build . putting the prop in a sleave like you have will make it more efficient. less cavitation so to speak .
It's called a kort nozzle.. or Azimuth drive ...there are several designs on the market German, French and UK and theres a company making retractable drives as he said. They have good thrust and are very safe the clear centered rim drive motors and blades have more advantages but both tend to top out at around ten knots but that is plenty for a sailing vessels auxillary propulsion. The one company that has designed a high-speed rim drive is the Italian Deep speed rim drive. .. it's more of an external water jet turbine.. more efficient though at higher speeds .. it's all external so no internal motor... There's a Transom mounted lifting stern drive system they can be bolted to and can be lifted out of the water to Allow beaching, removal and replacement and clearing. Top marks for doing this yourself.. 😎🧙🏼♂️🇬🇧 You can drive the motor from the center or use a rim driven electric motor.. They are safe and efficient but do require some fine hydrodynamic refinements . ..such as turblator rings and wavy edges on prop blades.. inspired by insects and whales.. the same company who makes the 3 types of auxiliary electric pod drives. 😉 If you're going to try best regen and optimum drive efficiency you might have to go down the tractor prop route. The other thing is is it possible to improve the efficiency by having a slightly wider entrance to the housing compared to the exit side from the prop. 🤔 all interesting stuff. RS/Pure built a regatta rescue center consul electric Rib in the UK using a retracting rim drive unit .. that pulled up in a open tunel in the rigid hull for shallow draft and running up the pebble beaches at speed. They built the rigid hull from flax and Basalt fiber .. for ballistic and abrasion resistance and the flax gave strength and lightness akin to carbon and beyond without the pollution and costs . It was also a lot greener and safer to produce compared to GRP or Carbon fiber.
When I saw your intro, and saw that you were planning to drive the boat with bow thrusters, I had to check that it wasn't April 1 already. 😂. Best of luck with the project. I'm sure you have worked it out.
🤣 Yes ... Not a great prop for propulsion... At least not for speed. The thing is though, Wilda is a sailboat, and the little bow thrusters provide amazing low speed thrust (for manoeuvring). Hopefully we'll be able to get a little bit of speed as well. Not much, but enough to get us going. If we don't get that balance good enough, we'll have to look at a higher pitch prop.... We'll see how the first tests go. Definitely not expecting a speed demon 🤣
@@buildingwilda As I said, I 'm sure tahat you have thought about it. If you have a look at the earlier Sailing Uma channel, you will see how they use their electric motor to dock, anchor and depart, then straight to the sails. You'll be fine.
Hi guys, I just watched it. I like the sound of the electric motors look forward to seeing how they go. Well done see you next week from Craig/ Sv one day .
The catamarans built in the Polynesians by the heritage societies and sailed around the Pacific had custom built electric outboards and solar panels. They were interesting but not powerful enough for extended use. I have electrified some displacement sailboats, all had gensets so were basically hybrids. Worked fine but they never got the regen they hoped for. Being a cat you should do better if they stand up to the stress of surfing. I heard of a cat that had two diesels and they were surfing so much that they put them in gear and the torque actually started the diesel. I also rebuilt a schooner built in 1938 that had an electric motor and a diesel built by a shipyard that built submarines.
I'm hoping to get better regen than most by using the prop we have... The drawback will be that it isn't any good at speed. When surfing down waves I intended to have the props retracted. We should generate enough power at much lower speeds..... I hope 🤣 Sounds like you have been on some interesting projects!
As an engineer it's very fascinating however fascinating isn't always safe and when you're crossing the ocean if any seal fails if anything fails on that system you're developing you will die, you should have just done a static placement of lower prop unit and a folding prop it would be much safer in the long run.... don't get me wrong it's a cool idea to get more efficiency by having it retract into the hole but in my opinion your safety is worth more than the slight efficiency you'll get by having a retracting system good luck
Absolutely right. If it was dependent on a seal. The top of the tube is well over the waterline, so should not be a problem. Can remove the unit entirely in the water. If it does break somehow, the boat itself has so many watertight sections we should still float really high.
Not sure about the 30% ..... But at least less power being wasted sideways. As for power efficiency... If a nozzle always made that sort of difference, all props would have shrouds of some sort. Props don't really throw that much water sideways, or paddlewheel.... It's a pressure differential thing that causes what's known as prop walk. Props work more like screws (really bad screws that slip all the time 🤣) that being said though.. if you look at props designed to direct thrust, they have nozzles and for good reason. To my knowledge, mostly in low speed high thrust applications. Pretty much what we are looking for.
@@buildingwilda i dont think engineers say kort nozzle's always make a difference, they do say kort shrouds make a big difference on heavy displacement hulls where you can't get up on plane, (like cruising catamarans & monohulls) it puzzles me that you've come this far and invested lots $ and think shaping a foil into your shroud is too much work (it doesn't have to be perfect to be effective BTW, you can roughly hand shape it to match plans online) you will see a difference in power and fuel economy since you will be running at lower RPM's than you would a non foiled shroud. But your build is still brilliant and im sure if will work well ..And Could you tell us where you bought the orange/red propeller? :) thx 🙏
Love this ! I’ve thought about this as an option ! Did you get different spec thrusters, the ones I know about have a short duty cycle.? These thruster tend to be very noisy so I expect you won’t plan on using very long anyway . A friend did similar tube in tube to create a gybing centerboard! Hmmm, my feeling is the gearbox should be in front so there is no restriction for the accelerated water to exit when in drive mode . But at least you can rotate the unit too and try it both ways if you not happy, in fact just comparing the thrust in fwd and reverse should tell you a lot! Re regen what I have read is you need a minimum 16”/400mm dia prop for regen but in a tube I don’t know . Cheers Warren
The thruster legs and props are from a hydraulic thruster capable of 30kw continuous. According to the manufacturer runtime should be pretty good. In reality I don't think they should be running for too long. We'll see how they go. I think the noise often comes from the way these are mounted more than the gearing... I'll try to mount them as quiet as possible. 12 (11.9)" prop, but huge area and low pitch, so I think it will turn for regen. There are also various settings to play with on the controller to optimise regen. I think it will be a good generator. I have my eyes on a different prop for increased speed performance.... That may be a way to go .. at the cost of less regeneration. Maybe two different props?... 🤔
I hope you recessed it into the outer skin of the Hull. This will give you a flush finish and make the install very clean and easy to do. The same way we mount through holes in race boats. Good luck
Very intersting concept. Besides that lower drag when retracted, this impeller style system should also have some energy efficiency benefits, due to less turbolences at the edges of the prop blades, as far as i know, when engineered correctly. Think it needs to have a very low distance from prop edges to the surrounding tube. And it gives protection to the propulsion system.
And it will also provide real Regen when we've been able to set it up right. High surface area, low pitch. Definitely won't give us high speeds, but that's not what it's for.
The propellers have a forward face (convex faces of the blades) and the rear or thrust faces. If you wish to optimise regeneration you will need to rotate your pods 180 degrees so the thrust faces face forward towards water flow to maximise rotational speed and torque. Easy to do with your setup. You are likely to find also that the prop pitch that provides the best boat speed is not the best pitch for optimum regen. I hope you show us your testing, please!
Yes. That is the idea. And the reason for going with a thruster prop... The low pitch and large surface area should be great for regen. The prop will not be great for propulsion... At least not for any speed. We have to decide which way to put them in soon... Clean water flow into the prop or clean thrust out ....
@@buildingwilda it has been said that a boat is a hole (two holes with a cat) in the water filled with compromises. Yes the low pitch suggests higher rotational speed during regen but less torque while more pitch would impart less speed but more torque. My feeling is that more pitch will be better as a low pitch propeller will be easier to stall as the charging load is increased? Yes more blade area should give more ‘grip’ on the water under power and better regen but with the compromise of increased rotational drag negating some of the benefit. Mount them as normal for propulsion then rotate the unit 180 to optimise clean water flow for regen. What is the pitch of your propellers? What speed will they turn at with those motors. A really interesting part of your overall project
Really interesting part of the project. Not the usual easy, diesel, way out. Will enjoy watching the process! I trust that you will have a generator back up for safety for those times you will be motoring off a lee shore for hours. I mean nothing but tremendous respect for what you have done on this project!
Thanks! A small generator should do the trick. And in worst case, an outboard, we'll be very conservative starting out. Until we really know our limits.
Being a thruster prop, it is made for high rpm. This suits direct drive electric very well. The drive leg has a 1.4:1 gearing. Should allow the motor and prop to turn close to optimal ranges ... Not perfect, but close. The faster we can get the prop to spin during regen, the better. I'd be super happy with anything above 500w, but I hope for 1000 in the right conditions. We'll see.
Really appreciate your exploring such a unique system, we all benefit from the courage to try something new. I'm unfamiliar with the prop in a tube, when it inevitably sucks some line in and fouls the prop, being in a tube could make it hard to untangle. I hope you experiment with directional thrust, that would give you amazing maneuverability
I've had the same thought.... I hope the nozzle stops some stuff from getting in there as well though... We'll see. Bound to happen at some point. I once got a tyre into a thruster and an icebox on another occasion... Not super easy to get rid of.
Its probably a bit late but i believe there are websites that can generate the curves you need. They give you a printable template that you wrap around the tube. I've seen people on other channels that using them when fabricating steel tubes.
Actually no. When the prop is placed in a shroud it doesn't really matter. If they were open I still think I wouldn't bother much. Propwalk can be as useful as it can be annoying. With these small short pitch props I don't think you'd notice much in any case.
Hi Guys, once again you're taking things to the next level. I love that you thought about drag and how to reduce it. However I am concerned you may be under powered in heavy seas or even coming to port in heavy winds for a safe anchorage. I'd suggest having 2 of these per hull, one close to the stern and the other 50-60% along the hull from the stern i.e. just forward from midships. You can not have it close to the bow as in heavy weather conditions the bow will be out of the water approx 50% of the time. If you had 2 each hull your regen capacity would double, meaning you could cope with a larger battery bank which in turn would give you a greater motoring range and higher power when and if needed. I'd like to see the cylinders, now stainless steel, be constructed from either fiberglass or carbon kevlar composite so that the bond between the hull and cylinder is as strong and stable as possible. With stainless steel / fiberglass join, specially under the waterline you will be relying on a sealant such as sikaflex and bolts. I'd be worried about the longevity of that. In any case, I would again suggest to create a water tight box around this assembly so if there is a "disaster" it's contained within the box and will not threaten the safety of the yacht. Also regarding the electric motors, have you looked at the radial flux motors? They are much lighter and thinner/narrower than standard electric motors. For the weight of your 10kw motor you could get at least a 25kw radial flux motor. That's a massive difference in power and regen when there's 4 units. Love that you're planning on them being rotating, another reason to have 4, you could maneuver the yacht to do a waltz in 50 knots of breeze lol Honestly you guys are putting more thought into your yacht than most of the high ticket yacht manufactures do. You're not just impressive, you're quickly becoming inspirational! Well done and thank you for sharing so much!
Thanks for your very kind comment! Originally i wanted to mount 2 drives diagonally. The thing is, space is very limited forward in these hulls. They are very narrow up front... I may have been able to squeeze one in forward, perhaps a smaller one. In the end I decided keeping them in the aft is more practical. I'd still like to add a small thruster up front at some point. Though it would provide some extra thrust, 4x25 kW is a 100kW draw from the battery. It would have to be a very big battery. And big cables, breakers etc. A lot of weight. 2x10 kW is not a huge amount of power. But really high torque low speed grunt. In some cases it may not be enough, we'll have to carefully learn our limits. Even with just two azimuth thrusters, we should be able to manoeuvre very nicely in any direction at any heading. (Would have been better with the diagonal setup)
I wanted to make the cylinders from fiberglass... It would just have been too time consuming. Couldn't get hold of the tube prefabricated and finding any suitable mold proved super difficult... Time was the real deal-breaker...
@@buildingwilda you've obviously given it lots of thought. When I have time I'll send you through some info on latest battery tech, I'm sure the weight you've allowed per kw of battery storage, if not been updated in the last few months, and I know you've both been extremely busy with hands on stuff haha, but you might be pleasantly surprised. 12 months ago it was roughly 900g /kw of battery storage, now it's less than 500g/kw and by the time your amazing yacht will be ready to launch I'd expect even lower weights per kw. Also a higher voltage circuit for your motors will reduce the weight as well. Lots to think about and even more to spend your money on LOL. Love the progress and the way you consider all options. Just a pleasure to watch! Once again, thank you!
@@buildingwilda This I understand, it's a complex moulding due to exact internal dimensions on one which is not so difficult but exact internal and external dimensions on the internal cylinder is complex in both the moulding and manufacturing process. That being said, bloody impressive when it's done! Hahaha
Love the concept and it is your version of an animus pod. As long as you get the thrust right,( easily achieved by changing the props). You will need at least 6 knots of boat speed. I am guessing you will fair in the thrust tube to the base as you progress your design. 🤙🏼🤙🏼🤙🏼🇦🇺
Thanks Yes... I foresee some different prop testing in the future 🤣 The tube will be cut flush with the hull and the various parts faired together. Thanks for watching
Love the idea, I'm doing similar on a Schionning Arrow1201 mind you with Hight thrust outboards with the eventual hope of refitting to electric propulsion in the future. I may have missed it, but what mechanism were you going to use to raise and lower? I'm torn between simple infallible fixed block and tackle or electric linear actuators.
It is, in effect, the system that Amel have used for their bow thruster for decades (think Super Maramu). Thoroughly well proven concept, albeit they dont use vectored thrust (but the topic has been proposed for emergency propulsion)
There are many versions of retractable propulsion. I work in a field where it is common. Most installs are either prohibitively expensive or not suitable to install for one reason or other. Most available solutions actually are both 🤣 We'll get to the vectored thrust once we are out in the water. For now, we'll be happy to just get the props to lift in and out of the water.. and spin 🤣
Yes .. they will... Like with most boats. It will be a bit of a challenge to handle, but with good insulation and bonding it should be alright. Also, most of the time most of it will be out of the water.
What about using a shaft driven setup with a folding prop? That seems extra complicated. I'm wondering how many knots your boat will go with this set up. I've never seen a set up like this before but it seems very similar to some of the bottom of some outboard engines with a prop guard.
@@buildingwildaI can't wait to see how it all works and then preforms. If you feel that you've made a mistake on this install than you can always change it latter on is some boat yard after you use it for a few years. Who knows, you might have come up with something everyone will want and set a new trend.
Oké than ! That’s an experiment 2.0. Interesting to see how long it will last. Obviously it will work but there are a couple items that can be a spoiler. That blade is not strong by it self. If you lose a blade the thing is in unbalance. It will result in rubbing the tube etc etc . What if something get stuck in side the vertical pipe. One bit of sea life and the system may jam. Loads of effort to make de hull flush must is that really a must. Are folding props equally efficient and effective.
Nothing is a must and everything is a compromise. Yes, there will be challenges. I think the blades will be plenty strong enough. And they are well protected by mostly not being in the water and by being in a nozzle when in use. If they are damaged, they are relatively cheap to replace. The tube will probably be jammed at some point... Plastic or a net or something.. but as they are supposed to be retracted most of the time, hopefully less often than a regular sail drive... I hope 🤣
I'm sure that could be an issue. A net would be worse. Hopefully the prop will go through seaweed. If not, then try reverse to spit it out.. if that doesn't work, likely the second one should be fine and I can go for a dive 🤣
Not too many low speed cruising regenerative forward facing propeller thruster designed sailboats. Even more unique is the vertical height adjustment. For decent regen, a combination of ideal sailing speeds of 7 to 12 knots and longer passages of days to weeks are usually required. So I am intrigued abiut the outcome and potential results. Cat speeds are usually better than mono hulls, which helps. Raising and lowering the propeller shroud will reduce drag when sailing vs motoring. More familiar with power generation from the round the world Imocas. Where tilting hydro vanes/generators were mounted on the transom. Yours is an in-hull mounted DIY hybrid concept combining elements of: a servo drive, thruster (bow/stern), a forward facing regenerative propeller system (optimizes regenerative capabilities), plus your height adjustment. Ingenious, unique, innovative.
:) And untried :) But well get it to work. With the prop we have, I hope we can generate usable power at lower speeds as well. At 7 to 12, we'll see what sort ofpower we get. I'm thinking it will be good. Unless we stall the prop. The whole setup will require some tweaking once we put it together. I really like the watt and sea generators. Their variable pitch prop racing model is amazing.. But 8000 euros last i checked... We'll try a high speed low torque towed setup as well.. I have some bits lined up in a box ready for testing... Not rocket science, so should be able to make something work.
Uma's owners were trolling boat shows looking for regen options. Limited selection due to boat size/weight, comfortable cruising speed 4 to 7 knots, depending on location and circumstance, cruising from 1 to 7 - 10 days. Compared to round the world Imocas going at 25 to 40 knots, sailing weeks or months at a time. So some planning, trial and error, lessons learned, charting some new ground. Need some speed to counter the regeneration drag. Then there is also sea state, ocean current and tidal changes.
Absolutely one of the biggest challenges... Electric requires fewer, though perhaps less available, spares. Building diy means you have to use off the shelf parts. Mostly, these should be cheaper and more easily available... Others less so. We have an extra controller, many breakers fuses etc. But that's really all .. I think our drives will generate usable power at pretty low speed... We'll see how low is practical. We can alter the parameters on the controller to tweak it once we get moving. Looking forward to that!
NIce to see a performance daggerboard cat with retractable motors. I don't get people putting daggerboards on cats with saildrives and permanent rudders. With this retractable setup you will be able to take the bottom in nice sandy lagoons like Middle Percy and North Zoe creek. I think you need to have retractable drives (usually outboards) or minikeels with diesels. I am very interested in your setup.
Actually the Schionning designs are designed to be be able to beach. Even with fixed rudders. I'd be very careful beaching though. Being able to lift the drives will certainly make it safer. But then there is the paint and sensors to consider as well. But I guess if you are careful in choosing a spot it should be fine. Looking forward to getting to those hard to get to places! The 45 cm loaded draft should make most places accessible.
@@buildingwilda I am careful but not that worried about beaching. I have two layers of 600gm double bias over a cedar strip core and have never had any damage on sand. I do use harder than normal antifouling. The depth sounder transducer is slightly up the round of the hull so it is fine. But nothing could get me on a cat that couldn't dry out - I love the places (like Percy, Hill inlet and Leekes Creek and Whathumba and Coongun creek) that require a cat to take the sand at low tide - great sand should not be a concern for a well built boat like yours. Cheers Phil
We want to put silicone antifouling on the boat, would be great in most cases. This kind of thing is what gets me leaning towards coppercoat instead though.
Hi Axel and Rox I used to work in construction of oli rigs made from steel tubulars and to make them fit togerher we had to curve the ends of tubes exactly the same as you have cut your thruster tunnel. There are simple proven methods for doing this which I am happy to show you if you are interested. It might be too late if you have already cut them but let me know if you are still interested. Great project you are doing by the way, love watching your weekly videos.
Thanks! That's kind of you. It was a little bit tricky to get right. Got it done in the end though. Now they fit nicely and will just need some cleaning around the edges.
Weve done the cutting already, and we got it pretty good with the help of some templating. Getting the inside and outside marking wasn't easy. In the end we cut perpendicular to the outside mark... Turned out best that way. What was your simple method?
@@buildingwilda it is not so easy to explain but you can develop paper templates that wrap around the pipe and show the cutting line. I used to draw them by hand but it is even easier now using cad. If you have to do it again I can show you.
Really two things.. The painter worked with Jotun near daily. Availability. Easy to get hold of. Hempel quattro is a superior high build primer (if you can live with the color) for coverage and sanding. I had good contacts at Hempel to start with but after covid they were gone, so we ended up going Jotun. All produce pretty much the same products at similar price and excellent quality.
Interesting since the prop is "going up and down" Just on a flat piece of metal/board would be better? (No tube around the prop)? First bit of bag or net or whatever and would be blocked? Just thinking as watching.
I'm hoping the tube will actually stop some stuff from getting to the prop in the first place. The purpose of the tube is to direct thrust more efficiently.
On the practical side, this prop enclosure and prop should be designed as a blender, you will definitely get crap in there 😊which is a major consideration. Personally, I would not see this a viable option because of the failure risks and pain of cleaning all the junk that will get stuck in there and continually changing broken props!
🤣 Certainly one way it might go 🤣 Hoping we won't have that problem so often though. Remember that most of the time the whole thing will be out of the water, unlike most other drive systems.
I actually don't understand why not more boats use a kort nozzle, especially one that can be rotated. It is more efficient than a naked prop and can direct thrust, so it can replace the rudder, which is especially useful at slow speeds. And with a slow-running prop like in the video, electric propulsion makes even less noise. At least to me this project is very logical...
From work, I don't think I ever see any nozzles on anything that travels at speed... Mostly tugs, offshore supply vessel and rigs have them. Slow speed high bollard pull. Some fixed with rudders, others azimuthing. For higher speed vessels, even in pods, I don't recall seeing many nozzles ...
@@buildingwilda yes, but then what is "higher speed"? A sailing boat needs a different propulsion at two times: 1) to maneuver independently of the wind (to get into a marina) or 2) to move despite lack of wind. For a sailboat, five knots is an acceptable speed. Tugs use kort nozzles mainly for manoeuvrability, submarines for efficiency, low noise and also speed. I think the main problem is that people got used to how things are done. Lots of people laughed at electric propulsion for quite some time, but now it's becoming more and more popular. And I expect some other things to change too in that process.
I'm sure you are right. Personally, I'm aiming to build a sailboat. That's what Schionning and a few others design. The cat will sail wind speed (hopefully better) in light winds. Love this type of design. The electric propulsion will hopefully just be for manoeuvring. I'm hope it can get us to 4-5 knots, but we'll see. I'll likely have to try a few different props. Sadly I don't have the ability to form an effective wing profile, so the nozzle will be quite crude.
@@buildingwilda I wish I had the space to build, I'd like to try that. So I still need to save a little longer and in the meantime I learn further. I do however not get along well with combustion engines, my preference is clearly electric. I can't understand how someone happily uses a machine that needs to be disassembled, cleaned and reassembled regularly when there are other solutions. My hope is to find a prop like in the video, for low RPMs, like on submarines, to avoid cavitation and noise. Then a duct to improve efficiency (again, submarines), plus rotation, like a Kort nozzle, to allow slow movement, when the rudder doesn't work anymore. Schionnings look good, but are slightly out of my league, I'm rather looking for a Prout. I have seen a few with electric motors and people survived it, so I'm hopeful...
Definitely an option. More so for a shaft or z-drive diesel propulsion system. There are no folding props really suitable for electric propulsion that in aware of.. there is an interesting variable pitch prop though that would achieve much the same result. I want something with large surface area and low pitch for two reasons. My motor works more efficiently on higher revs and the prop will be able to turn the motor easier and faster due to the low pitch high surface area. Plus . I want to get it to do directional thrust in the future. Hope you follow along!
Having sailed and lived aboard a 17m aluminium Crowther cat for 13 years I can tell you without doubt you will be caught in conditions you were not prepared for. Getting caught on a lee shore, running aground all things that occur REGULARLY. To that end you need enough drive in main engines to overcome windage (quite substantial with cats), current, waves etc. Emergency power is not needed often but you will need it. It can be the difference between running hard aground and losing your boat to arriving in a safe anchorage. Hybrid and electric boats do not have this capability. You can over rev a diesel for short periods for emergency drive, but not so with an electric motor. In fact the warmer your electric motor gets the lower the shaft output. All this said you need to be VERY careful when moving your boat given the lack of emergency drive available in your setup.
All drive systems have their advantages and disadvantages. Personally, i'm hoping the reliability of electric drive will outweigh the disadvantages. Few moving parts, nothing much to service, no clogged filters, dirty fuel fewer spares to carry. I absolutely realize a diesel is superior in some ways. In particular range under auxillary power. The 10kW motors have a peak output of 15kW for a short period, i think up to 20 seconds. Not much, and they would eat into the battery bank at an alarming rate at that sort of power. The battery bank is probably the weakest point of electric drives at this point. With a small gasoline generator I imagine we'll be able to get ourselves out of trouble. We'll have to do some real life testing once we are afloat and equip the boat with what we think we need.... And some things we hope we'll never need :) I love Crowthers designs! Hadn't actually heard of a 17m alloy boat by him though. Sounds epic.
Shouldn't that blade have a ring around it? To cut down on cavitation or move blade to back of the tube. The way it looks the tube will be damaged by cavitation and crack.
The tube will last many years before taking any serious damage from cavitation but I'm sure the paint will see some wear. The tube is chosen to match propeller size, or vice versa. Biggest prop I could fit and in a tube to match. About 2.5 mm clearance around it. I haven't seen any props built with a ring like you mention, other than on toy drones. I guess the rim drives would be similar to what you describe though. There is also some really weird twisted loop kind of looking prop being tried out on outboards... We'll see how we go with the prop we have. We may quite likely be testing other props in the future. Hope you stick around for more coming up.
True 🤣 A saying that has alot going for it. The up and down thing and the rotating bit may not be totally necessary.. But super useful. At least the electric drive will be vastly simpler than combustion alternatives. Fewer spares, fewer systems, fewer moving parts, fewer holes in the boat (but one large one🤣) less maintenance. Hope it works out ok. I think it will.
We think it would have been quite difficult to find someone professional to do this install for us, that wouldn't charge us a fortune, someone who would be available in the area and who would be willing to "test" along with us this very custom-made, unique drive system. We decided to do it the hard way and hope we won't regret it. If we fail, we'll probably find a "way out" eventually. Thanks for your comment and hope you return to watch the rest of it!
Golden Motors Chinese motor and drivers. Lots of info available online and if you can't find what you are looking for on the Chinese site, there is a good Canadian site to use. Golden Motors Canada. I bought direct from china. No issues at all, and fast communication.
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As an Engineer, this is highly intriguing to watch. Really interesting to see you work it out. I enjoy the process and progress! 😎🤘👍
Thank you! We are happy to learn that Axel's ideas and our project sparked so much interest and curiosity! We hope we turn it into a successful project! Thanks for commenting and a simple "like" and "share" go a long way! Hope to see you next Sunday!
the definition of Ducted props actually sets it as somewhat sensible within the sailing vessel realm.
the problem is the drag when not in use, However, that could be overcome by making it Also re-gen system.....prop re-gen can generate quite a bit of power, but many systems produce pathetic amounts of power because they don't include dedicated circuitry to handle the battery charging.....where with dedicated charging circuitry, prop re-gen could make more power than a deck full of solar panels ..... but the duct needs to be a revolved air foil for efficientcy, and airfoil duct design is complicated, being contingent on many parameters.
@@buildingwilda or to say, I would cut those PVC ducts as short as practically possible, and try to emulate an airfoil shape in the edge treatments.
and build dedicated battery charging circuits.
We will not be able to create an efficient foil in the duct. Perhaps something we can work with in the future.
The drag will be a non issue as the drive is retractable.
We don't have dedicated charging circuitry, but the controller is designed for regenerative breaking and this setting can be tuned to optimise regen.
The type of prop should lend itself nicely to regen .. I hope. And should be able to generate power at a much lower boat speed than other systems I've seen. Large surface area, low pitch... Should generate higher rpm earlier, leading to increased regen efficiency. We'll see how efficient... The drawback is speed under engine, but it's a sailboat ⛵
Thanks for the comments! Hope you stick around as we get it all together and into the water 🌊
@@buildingwilda Oh , Sorry, i didn't realize they were going to be made retractable...
the Sevcons don't regen so well....but it helps to dig into the programming and get what you can out of it....regen braking, on a wheeled vehicle, wants to push against battery voltage....where prop Regen, you want rectification into a large low voltage capacitor bank, and a switching boost regulator, to boost to charge from there.
This is cool, its been around for a while like you said. My favorite version used rim drives because they can pass ropes and other items through without fowling. The other versions also added and upper cap to keep the cavity protected, I also thing it kept to much seawater from being trapped inside the tube. You might want to add a way to remove any trapped seawater from the tube. If you want to be environmentally aware you can turn the propeller into a sort of a self washing machine by pumping some fresh water into the propeller tube. The fresh water is a hostile environment for the sea life that wants to attach to your equipment. I am not sure how much fresh water to add but I don't think it would take to much.
The not so environmentally nice way it to build a pocket in the tube for a bleach puck or some other method of injecting the water in the cavity with a cleaner, biodegradable soap is an option, but I'm not sure how much of a hostile environment it would create, and if you turn on the propellers well.... have you ever seen what happens in a washing machine and dish soap. You would leave a trail of bubbles as you sailed away.
13 hp motors seem pretty small fort the size of boat, but if you are okay with it I say go. I would recommend a 25 hp outboard or larger on your dingy and a mod on the back of the boat to allow for use on the full size boat in an emergency. That way you have a double duty backup.
It's a very cool concept, and I have only seen this on super yachts so this should be interesting to see how you solve your issues as they come up. Good Luck!
-MG
Very close to our thinking. A 25 hp dinghy outboard would be great. We'll see when we get there. Planning on a 3m is tender, so may be limited to a little less power.
As for the fouling in the cylinders... I'm hoping the lack of sunlight will keep growth down and almost all of the prop will be above the waterline when retracted.
Rim drives are super cool. Just not an economically viable option. Nor are any other retractable options. Even fixed commercially available options are extremely pricey... I think we'll get it working well. How well, remains to be seen.
This is an exciting project. However I don’t understand the gross negativity people have with your adventure - are they just trying to troll you. If they don’t like what you are doing - don’t watch. I am both intrigued and admire your efforts. Congratulations on attempting something different - from what I have seen so far, it’s going to be a grand adventure.
Thank you! Appreciate your constructive feedback and we try to keep our eyes and ears open to feedback in general! However, we don't want to take to heart the not so positive comments :) It is indeed a fantastic adventure and it's taking much longer than we would have ever thought. But now we're in it and we "have to dance to the music" :) Thanks again! Hope to see you next Sunday!
My first reaction is: not another electric catamaran.
Electricity is the worst thing in a sailboat. You can expect to have to replace all your electronics every few years (corrosion) if you don't get a lightning strike, then it's right away.
I have been in the bahamas in a tiny catamaran with two outboard (one for the boat, another for the dighy) and we had to use the one of the dighny multible times to get out of trouble.
I have seen many with luxury and complicated stuff break and people fall back on their dream of crusing because of tech that was broken.
Sailing is more about duck tape and mcgiver than any other thing I know.
If their dream is to build electronic stuff and fix it good, if their dream is to sail then this is *very* costly distraction.
I recommend reading: champagne cruising on a beer budget and looking at this channel: www.youtube.com/@samholmessailing to see how you can go sailing on great adventure on a tiny budget.
At the end, sailing is about the sea, the weather and the places you go way more than the boat.
Still a big fan of EV, Tesla, etc, just not on a boat (for now)
I think most of it comes from jealousy they can't or won't step out of thier comfort zone and hate those who do.
greatly respect your commitment to this, well done
Thank you 😊
Feels great bolting stuff together at last!
Excellent - this is a real engineering project and I wish you every success.👍⛵️😀
Thank you very much! Picked up a couple of modified couplings and key steel yesterday... Big things coming up.
The drive system has captured my imagination. Really looking forward to enjoying the progress in the coming weeks
There's more coming up
Nice to see the progress, it’s an interesting project you guys have.
Keep up the good work and I am looking forward to seeing the drives in action👍
So are we!
Maybe you can come give us a hand with some mechanical bits.... I can promise a quieter engine room than you are used to 🤣
WoW That is a revolution! Very interesting! Congratulations!
Thank you! With time we'll get it to revolve as well 🤣
Keep it up fantastic video i love watching the progress and seeing how you problem solve.
Thank you! Glad you enjoy watching our videos, we hope to keep it up! See you next week!
Thanks 👍Certainly more problems to solve coming up :)
Fantastic Axel and Rox , Cant wait for more of this electric propulsion build . putting the prop in a sleave like you have will make it more efficient. less cavitation so to speak .
Thanks Steve! See you soon
It's called a kort nozzle.. or Azimuth drive ...there are several designs on the market German, French and UK and theres a company making retractable drives as he said. They have good thrust and are very safe the clear centered rim drive motors and blades have more advantages but both tend to top out at around ten knots but that is plenty for a sailing vessels auxillary propulsion.
The one company that has designed a high-speed rim drive is the Italian Deep speed rim drive. .. it's more of an external water jet turbine.. more efficient though at higher speeds .. it's all external so no internal motor... There's a Transom mounted lifting stern drive system they can be bolted to and can be lifted out of the water to
Allow beaching, removal and replacement and clearing.
Top marks for doing this yourself.. 😎🧙🏼♂️🇬🇧
You can drive the motor from the center or use a rim driven electric motor..
They are safe and efficient but do require some fine hydrodynamic refinements . ..such as turblator rings and wavy edges on prop blades.. inspired by insects and whales.. the same company who makes the 3 types of auxiliary electric pod drives. 😉
If you're going to try best regen and optimum drive efficiency you might have to go down the tractor prop route.
The other thing is is it possible to improve the efficiency by having a slightly wider entrance to the housing compared to the exit side from the prop. 🤔 all interesting stuff.
RS/Pure built a regatta rescue center consul electric Rib in the UK using a retracting rim drive unit .. that pulled up in a open tunel in the rigid hull for shallow draft and running up the pebble beaches at speed.
They built the rigid hull from flax and Basalt fiber .. for ballistic and abrasion resistance and the flax gave strength and lightness akin to carbon and beyond without the pollution and costs .
It was also a lot greener and safer to produce compared to GRP or Carbon fiber.
Outstanding concept
Thanks! Hopefully we can get it to work ok as well 🤣
This approach to electric propulsion is really fascinating. I'll be very interested to see how it performs!
That was intriguing 😊😊
Unique. Hope it works
I love your drive system very innovative. Can't wait to see it finished
You and me both! Working on it.
Fantastic, as an sailor and engineer I really like the initiative and forward thinking
Thanks so much! Appreciate the interest and hope you come back next week for more!
When I saw your intro, and saw that you were planning to drive the boat with bow thrusters, I had to check that it wasn't April 1 already. 😂. Best of luck with the project. I'm sure you have worked it out.
🤣
Yes ...
Not a great prop for propulsion... At least not for speed. The thing is though, Wilda is a sailboat, and the little bow thrusters provide amazing low speed thrust (for manoeuvring).
Hopefully we'll be able to get a little bit of speed as well. Not much, but enough to get us going. If we don't get that balance good enough, we'll have to look at a higher pitch prop....
We'll see how the first tests go. Definitely not expecting a speed demon 🤣
@@buildingwilda As I said, I 'm sure tahat you have thought about it. If you have a look at the earlier Sailing Uma channel, you will see how they use their electric motor to dock, anchor and depart, then straight to the sails. You'll be fine.
That's what we've been thinking. Thanks! Really appreciate comments like yours. Hope you stick around for more.
Hi guys, I just watched it. I like the sound of the electric motors look forward to seeing how they go. Well done see you next week from Craig/ Sv one day .
Thanks 👍
We hope it works out good. We'll have our issues for sure, but we'll get it done.
The catamarans built in the Polynesians by the heritage societies and sailed around the Pacific had custom built electric outboards and solar panels. They were interesting but not powerful enough for extended use. I have electrified some displacement sailboats, all had gensets so were basically hybrids. Worked fine but they never got the regen they hoped for. Being a cat you should do better if they stand up to the stress of surfing. I heard of a cat that had two diesels and they were surfing so much that they put them in gear and the torque actually started the diesel. I also rebuilt a schooner built in 1938 that had an electric motor and a diesel built by a shipyard that built submarines.
I'm hoping to get better regen than most by using the prop we have... The drawback will be that it isn't any good at speed.
When surfing down waves I intended to have the props retracted. We should generate enough power at much lower speeds..... I hope 🤣
Sounds like you have been on some interesting projects!
As an engineer it's very fascinating however fascinating isn't always safe and when you're crossing the ocean if any seal fails if anything fails on that system you're developing you will die, you should have just done a static placement of lower prop unit and a folding prop it would be much safer in the long run.... don't get me wrong it's a cool idea to get more efficiency by having it retract into the hole but in my opinion your safety is worth more than the slight efficiency you'll get by having a retracting system good luck
Absolutely right. If it was dependent on a seal. The top of the tube is well over the waterline, so should not be a problem. Can remove the unit entirely in the water. If it does break somehow, the boat itself has so many watertight sections we should still float really high.
interesting to see it when finally finished , subbed
Thanks! It'll take a little while longer, but great to finally be working on it.
Hope you stick around
This is a variation of a Kurt’s nozzle. A Kurt’s nozzle improves the propeller thrust by approx 30%.
Yes. But we won't be shaping the nozzle into a foil shape. Too much work.
Bob, is that a “free” 30% increase in thrust, or is there a cost by way of higher current draw?
Not sure about the 30% ..... But at least less power being wasted sideways. As for power efficiency... If a nozzle always made that sort of difference, all props would have shrouds of some sort. Props don't really throw that much water sideways, or paddlewheel.... It's a pressure differential thing that causes what's known as prop walk. Props work more like screws (really bad screws that slip all the time 🤣) that being said though.. if you look at props designed to direct thrust, they have nozzles and for good reason. To my knowledge, mostly in low speed high thrust applications. Pretty much what we are looking for.
@@buildingwilda i dont think engineers say kort nozzle's always make a difference, they do say kort shrouds make a big difference on heavy displacement hulls where you can't get up on plane, (like cruising catamarans & monohulls) it puzzles me that you've come this far and invested lots $ and think shaping a foil into your shroud is too much work (it doesn't have to be perfect to be effective BTW, you can roughly hand shape it to match plans online) you will see a difference in power and fuel economy since you will be running at lower RPM's than you would a non foiled shroud. But your build is still brilliant and im sure if will work well ..And Could you tell us where you bought the orange/red propeller? :) thx 🙏
Love this ! I’ve thought about this as an option !
Did you get different spec thrusters, the ones I know about have a short duty cycle.?
These thruster tend to be very noisy so I expect you won’t plan on using very long anyway .
A friend did similar tube in tube to create a gybing centerboard!
Hmmm, my feeling is the gearbox should be in front so there is no restriction for the accelerated water to exit when in drive mode .
But at least you can rotate the unit too and try it both ways if you not happy, in fact just comparing the thrust in fwd and reverse should tell you a lot!
Re regen what I have read is you need a minimum 16”/400mm dia prop for regen but in a tube I don’t know .
Cheers Warren
The thruster legs and props are from a hydraulic thruster capable of 30kw continuous. According to the manufacturer runtime should be pretty good. In reality I don't think they should be running for too long. We'll see how they go. I think the noise often comes from the way these are mounted more than the gearing... I'll try to mount them as quiet as possible.
12 (11.9)" prop, but huge area and low pitch, so I think it will turn for regen. There are also various settings to play with on the controller to optimise regen.
I think it will be a good generator.
I have my eyes on a different prop for increased speed performance.... That may be a way to go .. at the cost of less regeneration. Maybe two different props?... 🤔
I just found you and your interesting project. I especially like folk who want to (or must) develop their own solutions. Keep up the good work!
Thanks! It's an interesting thought process. Challenging, but we'll get there. Hope you stick around for more.
I hope you recessed it into the outer skin of the Hull. This will give you a flush finish and make the install very clean and easy to do. The same way we mount through holes in race boats. Good luck
Maybe :) You'll have to stick around and see where we are in real time :) Thank you for the comment and for your interest and suggestion!
Very intersting concept. Besides that lower drag when retracted, this impeller style system should also have some energy efficiency benefits, due to less turbolences at the edges of the prop blades, as far as i know, when engineered correctly. Think it needs to have a very low distance from prop edges to the surrounding tube. And it gives protection to the propulsion system.
And it will also provide real Regen when we've been able to set it up right.
High surface area, low pitch.
Definitely won't give us high speeds, but that's not what it's for.
Unique design
Thank you! Indeed, we think it's unique, thus not easy! but we hope it works as planned!
The propellers have a forward face (convex faces of the blades) and the rear or thrust faces. If you wish to optimise regeneration you will need to rotate your pods 180 degrees so the thrust faces face forward towards water flow to maximise rotational speed and torque. Easy to do with your setup. You are likely to find also that the prop pitch that provides the best boat speed is not the best pitch for optimum regen. I hope you show us your testing, please!
Yes. That is the idea. And the reason for going with a thruster prop... The low pitch and large surface area should be great for regen. The prop will not be great for propulsion... At least not for any speed.
We have to decide which way to put them in soon... Clean water flow into the prop or clean thrust out ....
@@buildingwilda it has been said that a boat is a hole (two holes with a cat) in the water filled with compromises. Yes the low pitch suggests higher rotational speed during regen but less torque while more pitch would impart less speed but more torque. My feeling is that more pitch will be better as a low pitch propeller will be easier to stall as the charging load is increased? Yes more blade area should give more ‘grip’ on the water under power and better regen but with the compromise of increased rotational drag negating some of the benefit.
Mount them as normal for propulsion then rotate the unit 180 to optimise clean water flow for regen.
What is the pitch of your propellers? What speed will they turn at with those motors. A really interesting part of your overall project
Really interesting part of the project. Not the usual easy, diesel, way out. Will enjoy watching the process! I trust that you will have a generator back up for safety for those times you will be motoring off a lee shore for hours. I mean nothing but tremendous respect for what you have done on this project!
Thanks!
A small generator should do the trick. And in worst case, an outboard, we'll be very conservative starting out. Until we really know our limits.
Being a thruster prop, it is made for high rpm. This suits direct drive electric very well. The drive leg has a 1.4:1 gearing. Should allow the motor and prop to turn close to optimal ranges ... Not perfect, but close. The faster we can get the prop to spin during regen, the better. I'd be super happy with anything above 500w, but I hope for 1000 in the right conditions. We'll see.
Really appreciate your exploring such a unique system, we all benefit from the courage to try something new. I'm unfamiliar with the prop in a tube, when it inevitably sucks some line in and fouls the prop, being in a tube could make it hard to untangle. I hope you experiment with directional thrust, that would give you amazing maneuverability
I've had the same thought.... I hope the nozzle stops some stuff from getting in there as well though... We'll see. Bound to happen at some point. I once got a tyre into a thruster and an icebox on another occasion... Not super easy to get rid of.
Its probably a bit late but i believe there are websites that can generate the curves you need. They give you a printable template that you wrap around the tube. I've seen people on other channels that using them when fabricating steel tubes.
Thanks.
I used my cad of the shroud to generate a set of measurements. Transferred that to paper (no printer close by) and to the tube. Thanks
Will you have the props counter-rotating to eliminate prop walk?
Actually no. When the prop is placed in a shroud it doesn't really matter.
If they were open I still think I wouldn't bother much. Propwalk can be as useful as it can be annoying. With these small short pitch props I don't think you'd notice much in any case.
Hi Guys, once again you're taking things to the next level.
I love that you thought about drag and how to reduce it.
However I am concerned you may be under powered in heavy seas or even coming to port in heavy winds for a safe anchorage.
I'd suggest having 2 of these per hull, one close to the stern and the other 50-60% along the hull from the stern i.e. just forward from midships. You can not have it close to the bow as in heavy weather conditions the bow will be out of the water approx 50% of the time.
If you had 2 each hull your regen capacity would double, meaning you could cope with a larger battery bank which in turn would give you a greater motoring range and higher power when and if needed.
I'd like to see the cylinders, now stainless steel, be constructed from either fiberglass or carbon kevlar composite so that the bond between the hull and cylinder is as strong and stable as possible. With stainless steel / fiberglass join, specially under the waterline you will be relying on a sealant such as sikaflex and bolts. I'd be worried about the longevity of that.
In any case, I would again suggest to create a water tight box around this assembly so if there is a "disaster" it's contained within the box and will not threaten the safety of the yacht.
Also regarding the electric motors, have you looked at the radial flux motors? They are much lighter and thinner/narrower than standard electric motors. For the weight of your 10kw motor you could get at least a 25kw radial flux motor. That's a massive difference in power and regen when there's 4 units.
Love that you're planning on them being rotating, another reason to have 4, you could maneuver the yacht to do a waltz in 50 knots of breeze lol
Honestly you guys are putting more thought into your yacht than most of the high ticket yacht manufactures do.
You're not just impressive, you're quickly becoming inspirational!
Well done and thank you for sharing so much!
Thanks for your very kind comment!
Originally i wanted to mount 2 drives diagonally. The thing is, space is very limited forward in these hulls. They are very narrow up front... I may have been able to squeeze one in forward, perhaps a smaller one. In the end I decided keeping them in the aft is more practical. I'd still like to add a small thruster up front at some point.
Though it would provide some extra thrust, 4x25 kW is a 100kW draw from the battery. It would have to be a very big battery. And big cables, breakers etc. A lot of weight.
2x10 kW is not a huge amount of power. But really high torque low speed grunt. In some cases it may not be enough, we'll have to carefully learn our limits.
Even with just two azimuth thrusters, we should be able to manoeuvre very nicely in any direction at any heading. (Would have been better with the diagonal setup)
I wanted to make the cylinders from fiberglass... It would just have been too time consuming. Couldn't get hold of the tube prefabricated and finding any suitable mold proved super difficult... Time was the real deal-breaker...
@@buildingwilda you've obviously given it lots of thought.
When I have time I'll send you through some info on latest battery tech, I'm sure the weight you've allowed per kw of battery storage, if not been updated in the last few months, and I know you've both been extremely busy with hands on stuff haha, but you might be pleasantly surprised.
12 months ago it was roughly 900g /kw of battery storage, now it's less than 500g/kw and by the time your amazing yacht will be ready to launch I'd expect even lower weights per kw.
Also a higher voltage circuit for your motors will reduce the weight as well.
Lots to think about and even more to spend your money on LOL.
Love the progress and the way you consider all options. Just a pleasure to watch!
Once again, thank you!
@@buildingwilda This I understand, it's a complex moulding due to exact internal dimensions on one which is not so difficult but exact internal and external dimensions on the internal cylinder is complex in both the moulding and manufacturing process.
That being said, bloody impressive when it's done! Hahaha
Love the concept and it is your version of an animus pod. As long as you get the thrust right,( easily achieved by changing the props). You will need at least 6 knots of boat speed. I am guessing you will fair in the thrust tube to the base as you progress your design. 🤙🏼🤙🏼🤙🏼🇦🇺
Thanks
Yes... I foresee some different prop testing in the future 🤣
The tube will be cut flush with the hull and the various parts faired together.
Thanks for watching
Amazing!
Love the idea, I'm doing similar on a Schionning Arrow1201 mind you with Hight thrust outboards with the eventual hope of refitting to electric propulsion in the future. I may have missed it, but what mechanism were you going to use to raise and lower? I'm torn between simple infallible fixed block and tackle or electric linear actuators.
Electric linear actuators. A bit more work, but should in the end have some advantages.
High thrust outboards will work great.
It is, in effect, the system that Amel have used for their bow thruster for decades (think Super Maramu). Thoroughly well proven concept, albeit they dont use vectored thrust (but the topic has been proposed for emergency propulsion)
There are many versions of retractable propulsion. I work in a field where it is common.
Most installs are either prohibitively expensive or not suitable to install for one reason or other. Most available solutions actually are both 🤣
We'll get to the vectored thrust once we are out in the water. For now, we'll be happy to just get the props to lift in and out of the water.. and spin 🤣
Are all your different metals not going to cause issues under the water?
Yes .. they will... Like with most boats. It will be a bit of a challenge to handle, but with good insulation and bonding it should be alright. Also, most of the time most of it will be out of the water.
What about using a shaft driven setup with a folding prop? That seems extra complicated. I'm wondering how many knots your boat will go with this set up. I've never seen a set up like this before but it seems very similar to some of the bottom of some outboard engines with a prop guard.
It won't be fast, that's for sure! 🤣 All solutions have their own merits. And there are many different ways to get a prop to spin 🤣
@@buildingwildaI can't wait to see how it all works and then preforms. If you feel that you've made a mistake on this install than you can always change it latter on is some boat yard after you use it for a few years. Who knows, you might have come up with something everyone will want and set a new trend.
Oké than !
That’s an experiment 2.0. Interesting to see how long it will last.
Obviously it will work but there are a couple items that can be a spoiler.
That blade is not strong by it self. If you lose a blade the thing is in unbalance. It will result in rubbing the tube etc etc .
What if something get stuck in side the vertical pipe. One bit of sea life and the system may jam.
Loads of effort to make de hull flush must is that really a must. Are folding props equally efficient and effective.
How will it deal with weed etc going into the shroud?
Nothing is a must and everything is a compromise.
Yes, there will be challenges. I think the blades will be plenty strong enough. And they are well protected by mostly not being in the water and by being in a nozzle when in use. If they are damaged, they are relatively cheap to replace.
The tube will probably be jammed at some point... Plastic or a net or something.. but as they are supposed to be retracted most of the time, hopefully less often than a regular sail drive... I hope 🤣
I'm sure that could be an issue. A net would be worse. Hopefully the prop will go through seaweed. If not, then try reverse to spit it out.. if that doesn't work, likely the second one should be fine and I can go for a dive 🤣
Retractable azipods and ducted, cool
Not too many low speed cruising regenerative forward facing propeller thruster designed sailboats. Even more unique is the vertical height adjustment. For decent regen, a combination of ideal sailing speeds of 7 to 12 knots and longer passages of days to weeks are usually required. So I am intrigued abiut the outcome and potential results. Cat speeds are usually better than mono hulls, which helps. Raising and lowering the propeller shroud will reduce drag when sailing vs motoring.
More familiar with power generation from the round the world Imocas. Where tilting hydro vanes/generators were mounted on the transom. Yours is an in-hull mounted DIY hybrid concept combining elements of: a servo drive, thruster (bow/stern), a forward facing regenerative propeller system (optimizes regenerative capabilities), plus your height adjustment. Ingenious, unique, innovative.
:) And untried :) But well get it to work. With the prop we have, I hope we can generate usable power at lower speeds as well. At 7 to 12, we'll see what sort ofpower we get. I'm thinking it will be good. Unless we stall the prop. The whole setup will require some tweaking once we put it together.
I really like the watt and sea generators. Their variable pitch prop racing model is amazing.. But 8000 euros last i checked... We'll try a high speed low torque towed setup as well.. I have some bits lined up in a box ready for testing... Not rocket science, so should be able to make something work.
Uma's owners were trolling boat shows looking for regen options. Limited selection due to boat size/weight, comfortable cruising speed 4 to 7 knots, depending on location and circumstance, cruising from 1 to 7 - 10 days. Compared to round the world Imocas going at 25 to 40 knots, sailing weeks or months at a time.
So some planning, trial and error, lessons learned, charting some new ground. Need some speed to counter the regeneration drag. Then there is also sea state, ocean current and tidal changes.
Other hindrances, reliable availability options, costs, design/troubleshooting support/spares availability in the furthest reaches.
Absolutely one of the biggest challenges...
Electric requires fewer, though perhaps less available, spares. Building diy means you have to use off the shelf parts. Mostly, these should be cheaper and more easily available... Others less so. We have an extra controller, many breakers fuses etc. But that's really all ..
I think our drives will generate usable power at pretty low speed... We'll see how low is practical. We can alter the parameters on the controller to tweak it once we get moving. Looking forward to that!
A performance cat should be a better platform for regeneration.. we should be sailing wind speed up to 10-15 knots I hope...
NIce to see a performance daggerboard cat with retractable motors. I don't get people putting daggerboards on cats with saildrives and permanent rudders. With this retractable setup you will be able to take the bottom in nice sandy lagoons like Middle Percy and North Zoe creek. I think you need to have retractable drives (usually outboards) or minikeels with diesels. I am very interested in your setup.
Actually the Schionning designs are designed to be be able to beach. Even with fixed rudders. I'd be very careful beaching though. Being able to lift the drives will certainly make it safer.
But then there is the paint and sensors to consider as well. But I guess if you are careful in choosing a spot it should be fine. Looking forward to getting to those hard to get to places! The 45 cm loaded draft should make most places accessible.
@@buildingwilda I am careful but not that worried about beaching. I have two layers of 600gm double bias over a cedar strip core and have never had any damage on sand. I do use harder than normal antifouling. The depth sounder transducer is slightly up the round of the hull so it is fine. But nothing could get me on a cat that couldn't dry out - I love the places (like Percy, Hill inlet and Leekes Creek and Whathumba and Coongun creek) that require a cat to take the sand at low tide - great sand should not be a concern for a well built boat like yours. Cheers Phil
We want to put silicone antifouling on the boat, would be great in most cases. This kind of thing is what gets me leaning towards coppercoat instead though.
Too interesting to pass. New subbie here 😊
Welcome! We'll see if we can keep you interested 🤣 Perhaps not too many epic failures 🤣
Hi Axel and Rox
I used to work in construction of oli rigs made from steel tubulars and to make them fit togerher we had to curve the ends of tubes exactly the same as you have cut your thruster tunnel. There are simple proven methods for doing this which I am happy to show you if you are interested. It might be too late if you have already cut them but let me know if you are still interested.
Great project you are doing by the way, love watching your weekly videos.
Thanks! That's kind of you. It was a little bit tricky to get right. Got it done in the end though. Now they fit nicely and will just need some cleaning around the edges.
Weve done the cutting already, and we got it pretty good with the help of some templating. Getting the inside and outside marking wasn't easy. In the end we cut perpendicular to the outside mark... Turned out best that way.
What was your simple method?
@@buildingwilda it is not so easy to explain but you can develop paper templates that wrap around the pipe and show the cutting line. I used to draw them by hand but it is even easier now using cad. If you have to do it again I can show you.
What made you decide to use jotun paint over other brands about to start the painting process on my schionning
Really two things..
The painter worked with Jotun near daily.
Availability. Easy to get hold of.
Hempel quattro is a superior high build primer (if you can live with the color) for coverage and sanding. I had good contacts at Hempel to start with but after covid they were gone, so we ended up going Jotun.
All produce pretty much the same products at similar price and excellent quality.
you will be using a standard 3 or 4 blade prop correct? as that one is only made for very slow movement and not suitable for higher speeds
We're aware of the limitations of the prop. Slow speed only is what it's for. High speed under sail.
Surely you want it in the water for regen, to generate electricity while sailing?
Yes. Absolutely. But only then or when used as propulsion. Not all the time.
Interesting
since the prop is "going up and down"
Just on a flat piece of metal/board would be better? (No tube around the prop)?
First bit of bag or net or whatever and would be blocked?
Just thinking as watching.
I'm hoping the tube will actually stop some stuff from getting to the prop in the first place.
The purpose of the tube is to direct thrust more efficiently.
On the practical side, this prop enclosure and prop should be designed as a blender, you will definitely get crap in there 😊which is a major consideration.
Personally, I would not see this a viable option because of the failure risks and pain of cleaning all the junk that will get stuck in there and continually changing broken props!
🤣 Certainly one way it might go 🤣 Hoping we won't have that problem so often though. Remember that most of the time the whole thing will be out of the water, unlike most other drive systems.
I actually don't understand why not more boats use a kort nozzle, especially one that can be rotated. It is more efficient than a naked prop and can direct thrust, so it can replace the rudder, which is especially useful at slow speeds. And with a slow-running prop like in the video, electric propulsion makes even less noise. At least to me this project is very logical...
From work, I don't think I ever see any nozzles on anything that travels at speed...
Mostly tugs, offshore supply vessel and rigs have them. Slow speed high bollard pull. Some fixed with rudders, others azimuthing.
For higher speed vessels, even in pods, I don't recall seeing many nozzles ...
@@buildingwilda yes, but then what is "higher speed"? A sailing boat needs a different propulsion at two times: 1) to maneuver independently of the wind (to get into a marina) or 2) to move despite lack of wind. For a sailboat, five knots is an acceptable speed. Tugs use kort nozzles mainly for manoeuvrability, submarines for efficiency, low noise and also speed.
I think the main problem is that people got used to how things are done. Lots of people laughed at electric propulsion for quite some time, but now it's becoming more and more popular. And I expect some other things to change too in that process.
I'm sure you are right. Personally, I'm aiming to build a sailboat. That's what Schionning and a few others design. The cat will sail wind speed (hopefully better) in light winds. Love this type of design.
The electric propulsion will hopefully just be for manoeuvring. I'm hope it can get us to 4-5 knots, but we'll see. I'll likely have to try a few different props. Sadly I don't have the ability to form an effective wing profile, so the nozzle will be quite crude.
@@buildingwilda I wish I had the space to build, I'd like to try that. So I still need to save a little longer and in the meantime I learn further. I do however not get along well with combustion engines, my preference is clearly electric. I can't understand how someone happily uses a machine that needs to be disassembled, cleaned and reassembled regularly when there are other solutions.
My hope is to find a prop like in the video, for low RPMs, like on submarines, to avoid cavitation and noise. Then a duct to improve efficiency (again, submarines), plus rotation, like a Kort nozzle, to allow slow movement, when the rudder doesn't work anymore.
Schionnings look good, but are slightly out of my league, I'm rather looking for a Prout. I have seen a few with electric motors and people survived it, so I'm hopeful...
Why not just use a folding prop?
Definitely an option. More so for a shaft or z-drive diesel propulsion system.
There are no folding props really suitable for electric propulsion that in aware of.. there is an interesting variable pitch prop though that would achieve much the same result.
I want something with large surface area and low pitch for two reasons. My motor works more efficiently on higher revs and the prop will be able to turn the motor easier and faster due to the low pitch high surface area.
Plus . I want to get it to do directional thrust in the future.
Hope you follow along!
Having sailed and lived aboard a 17m aluminium Crowther cat for 13 years I can tell you without doubt you will be caught in conditions you were not prepared for. Getting caught on a lee shore, running aground all things that occur REGULARLY. To that end you need enough drive in main engines to overcome windage (quite substantial with cats), current, waves etc. Emergency power is not needed often but you will need it. It can be the difference between running hard aground and losing your boat to arriving in a safe anchorage. Hybrid and electric boats do not have this capability. You can over rev a diesel for short periods for emergency drive, but not so with an electric motor. In fact the warmer your electric motor gets the lower the shaft output. All this said you need to be VERY careful when moving your boat given the lack of emergency drive available in your setup.
Wow! What an inspired project.
Good luck with it.
Cheers, Hugh
All drive systems have their advantages and disadvantages. Personally, i'm hoping the reliability of electric drive will outweigh the disadvantages. Few moving parts, nothing much to service, no clogged filters, dirty fuel fewer spares to carry.
I absolutely realize a diesel is superior in some ways. In particular range under auxillary power. The 10kW motors have a peak output of 15kW for a short period, i think up to 20 seconds. Not much, and they would eat into the battery bank at an alarming rate at that sort of power. The battery bank is probably the weakest point of electric drives at this point. With a small gasoline generator I imagine we'll be able to get ourselves out of trouble.
We'll have to do some real life testing once we are afloat and equip the boat with what we think we need.... And some things we hope we'll never need :)
I love Crowthers designs! Hadn't actually heard of a 17m alloy boat by him though. Sounds epic.
Shouldn't that blade have a ring around it? To cut down on cavitation or move blade to back of the tube. The way it looks the tube will be damaged by cavitation and crack.
The tube will last many years before taking any serious damage from cavitation but I'm sure the paint will see some wear.
The tube is chosen to match propeller size, or vice versa. Biggest prop I could fit and in a tube to match. About 2.5 mm clearance around it. I haven't seen any props built with a ring like you mention, other than on toy drones. I guess the rim drives would be similar to what you describe though. There is also some really weird twisted loop kind of looking prop being tried out on outboards...
We'll see how we go with the prop we have. We may quite likely be testing other props in the future.
Hope you stick around for more coming up.
I think its a bad idea and will lead to problems with debris, and difficulty cleaning it out.
In some cases it might. But most of the time, it will be out of the water. So less issues ideally. . hopefully 🤣 we'll see how it goes
Sorry simple is better know the work kiss?
True 🤣 A saying that has alot going for it.
The up and down thing and the rotating bit may not be totally necessary.. But super useful.
At least the electric drive will be vastly simpler than combustion alternatives.
Fewer spares, fewer systems, fewer moving parts, fewer holes in the boat (but one large one🤣) less maintenance.
Hope it works out ok. I think it will.
I think maybe you should’ve got a professional to install this but good luck anyway
We think it would have been quite difficult to find someone professional to do this install for us, that wouldn't charge us a fortune, someone who would be available in the area and who would be willing to "test" along with us this very custom-made, unique drive system. We decided to do it the hard way and hope we won't regret it. If we fail, we'll probably find a "way out" eventually. Thanks for your comment and hope you return to watch the rest of it!
This is cool
Can i ask where you gat engine from and what price range. No need directly id you understand.
Just curiouse and anger to make some here my self
Golden Motors
Chinese motor and drivers. Lots of info available online and if you can't find what you are looking for on the Chinese site, there is a good Canadian site to use. Golden Motors Canada.
I bought direct from china. No issues at all, and fast communication.
Nice to see the progress, it’s an interesting project you guys have.
Keep up the good work and I am looking forward to seeing the drives in action👍
Thanks! Will do! So are we ☺️