Affordable, long-term liveaboard?

Discussion in 'Projects & Proposals' started by Filmdaddy, Aug 4, 2005.

  1. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    How feasible are kite sails by now? I haven't found a thread discussing them. I also look to them as an "upgrade" to a solar powered boat that don't require a long mast or stays and with some "auto pilot" could work brilliantly in the future. But from what I've seen they are still not quite there yet.

    BTW instead of wind turbines you could also look into generating electricity using kite sails. There is a delft university research project on youtube showing kite sail power generators. They should be cheaper and easier to put on a boat than an efficient wind turbine. Winds higher up are more powerful. No stability problem. And if you want a kite sail anyways they are kind of free.

    This is a rough 3D sketch of what I would imagine for a solar powered proa. 15m long, 3m wide cabin, 42.5m² solar roof. I'll make cabin maybe one row longer towards the end, the awning of bifacial panels one column wider and the small hull a bit longer and support the awning with lightweight fiberglass trusses towards the smaller hull.
    Since I want / need to build myself I want to use simple shapes. Except for the front, but it's hard to make it good looking otherwise.
    You could make the shape more areodynamic sideways but then you either loose solar roof surface or transportation gets more tricky. The need to maximize solar roof surface really makes aerodynamics tricky.

    Trimarani v24 26.jpg

    PS: I think foam core at 20 or 30mm thickness improves interior space compared to aluminium with stringers and bulkheads. But if I had the money to have one build and for more battery capacity I might go for it too.
     
  2. Angélique
    Joined: Feb 2009
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    Angélique aka Angel (only by name)

    Dejay likes this.
  3. Dejay
    Joined: Mar 2018
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    Location: Europe

    Dejay Senior Newbie

    Thanks Angelique! Great thread. Found another thread here.
    Another large field to learn about... I'll have to look into this later and ask the guys from wingit kite boat systems about the automated system. For larger passages you really need some kind of computer controlled automated steering system for the kite.
     
  4. Kai Rabenstein
    Joined: Jan 2019
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    Location: Hastings, UK

    Kai Rabenstein Junior Member

    That's a great looking design Dejay! I am fascinated by the proa approach, too - Aspen's C120 from Washington state in the USA is a seriously cool commercial design for example. I got another kite sail commercial reference from Francois Lucas which I will look up and post here. My own boat is limited to 5 metres beam though because I want to preserve the option of traversing the French canals and also fit into most regular marina berths.
     
  5. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Thanks! And I'd prefer the same in regards to french canals! I'm wondering if a proa design could work where you can pull the vaka in to get to 5m. There are enough rivers that allow 8m beam but the french canals would be good to go to the Mediterranean sea for winter.

    I'm also not sure about stability and weight of trimaran vs proa. Proa might need ballast in vaka for enough stability, but I don't quite understand this yet.
    While trimaran doesn't and could end up with less weight and less resistance and more solar range. But I like the single large bridge deck due to the asymmetry of the proa.

    Is there any info on how big the usual marina berths are? Unfortunately I have almost no experience boating.

    Yeah the C120 looks really nice! Didn't know this kind of proa design makes sense.
     
  6. Kai Rabenstein
    Joined: Jan 2019
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    Location: Hastings, UK

    Kai Rabenstein Junior Member

    Here as promised the kite sail reference (LibertyKite : Offrez un kite à votre bateau https://libertykite.com) - my correspondent Francois Lucas (marine designer based in Nantes) says he has also some personal experience with the alternative Omegasail design which he found to be awkward to handle and unresponsive; it certainly does not seem to sell well and their website (www.omegasails.com) has not been revised in a very long time.
     
  7. Kai Rabenstein
    Joined: Jan 2019
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    Location: Hastings, UK

    Kai Rabenstein Junior Member

    The 19th century Freycinet gauge canal dimensions (or, to put it more correctly, the classic French peniche barge dimensions and canal bridge arches) also impose an air height of 3.5 metres which - given that I'd really like to have a flybridge - is a serious design challenge: Especially considering also the need for maximum soar panel surface area ... I am currently wondering if it might be feasible to build extendable side wings covered with solar panels (think dragonfly wings). Most marina berths have a maximum service beam of 4.5 metres, too - wider beamed boats tend to have to lie at the (few) pontoon heads and are charged considerably more. Hence the 4.5 metre beam planned for my boat. There is a German commercial design for a motorised sideways extendable multihull sailing yacht - I will track this down and post a link.
     
  8. Kai Rabenstein
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    Location: Hastings, UK

    Kai Rabenstein Junior Member

  9. Dejay
    Joined: Mar 2018
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    Location: Europe

    Dejay Senior Newbie

    Thanks for the info and links, will check that out. A trimaran is probably better for the idea of reducing width, since weight is on the central hull already. 4.5m would seem rather narrow for an 12m cat.

    From what I've read here on the forum the omega sail works great for what it's designed to do, sail downwind. Easy to use, doesn't need controlling and stays upright on it's own.

    Have you spoken with kite-boat-systems.com? They seem to be the only ones offering an actually automated control system for yachts. I'd love to know how well that actually works for a power cat. But for me the boat has to work on solar alone + small generator and outboarder for backup. I'd definitely would want to get resistance values for your planned boat and estimate power gain and speed and range before committing to a design.

    Also found a research paper on kite power control systems and these threads:
    Ocean Kite Sailing-How to solve the problems with very light airs and sudden squalls?
    Kite power for boats - boats powerd by kites
    New Age Trawler/Motorsailer; Kite assisted PowerYacht


    "Flaps" definitely can work, see the planet solar. You could either have them slide out and be fixed on rails (the sketch I posted was supposed to be an example of this) or have them fold out. Folding could also allow angling them for more solar gain, but they would be upside down on top of your solar panels when stowed. The problem with overhangs or "solar awnings" is that it's the worst kind of wind coefficient and added drag with sideways wind.

    Attached is a list of solar powered yachts and conversions and experiments I've found so far. Anyone know any other examples?
    The "Cs" is the "solar coefficient" an estimate for performance:
    Cs = Solar Area * Length / Displacement (lightship)
     

    Attached Files:


  10. J Smythe
    Joined: Jul 2019
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    Location: USA

    J Smythe Junior Member

    I fear those things. I have nightmares of delamination, or hull breaches resulting in water logged foam core.

    I wish I could afford to buy and maintain a nice steele boat, but that's not going to happen.
     
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