Propulsion system for a sailing proa

Discussion in 'Multihulls' started by multihullsailor, Dec 7, 2007.

  1. multihullsailor
    Joined: Nov 2007
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    Location: Cape Town

    multihullsailor Junior Member

    What ideas abound regarding the engine power and propulsion system for a sailing proa intended for worldwide long-term cruising?

    As the proa sails in both directions, any chosen system should lift clear of the water. For total security reasons I would not want any part of the propulsion system to exit a hull under the waterline. I'd be happy to "designate" a "power-only" direction, like larger leeward hull always to port under power, and would want twin propulsions for marina action.

    So, the big question: twin lifting outboards, twin electric drives, twin hydraulic drives (the latter two both linked to one diesel power plant)? Lifting Silette drives or lifting outboard drives? Lifting straight shafts? What about jet drives?:idea:


    Roger
     
  2. DGreenwood
    Joined: Aug 2004
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    Location: New York

    DGreenwood Senior Member

    Many small work platforms use outboards that rotate 360 degrees. Why not do that? It's pretty simple.
    Although if you put it in the fore/aft center of the boat it won't afford much steering control.
     
  3. Alan M.
    Joined: Jan 2006
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    Location: Queensland

    Alan M. Senior Member

    You could use 2 outboards - one larger one, mounted close to the windward hull, for motoring, and a smaller one, near the leeward hull, for maneouvering only.
     
  4. tcpbob
    Joined: Dec 2007
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    tcpbob Junior Member

    Hey Alan M

    Thats far to simple and elegant to work.. how about something way more expensive and complex..
     
  5. Trevlyns
    Joined: Oct 2006
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    Trevlyns Senior Citizen/Member

    Most respectfully, Roger – I think you may be missing the point.

    A proa is a very basic sailing craft – [your quote] - twin lifting outboards, twin electric drives, twin hydraulic drives (the latter two both linked to one diesel power plant)? Lifting Silette drives or lifting outboard drives? Lifting straight shafts? What about jet drives?

    The purists would be horrified! :D Features like these belong on the rich boys’ 60ft + catamarans and other floating hotels and brothels.

    Essentially, on a proa, you’re only driving one hull and I’d advocate the KISS system – the more basic a proa, the better.

    As I mentioned when you first posted this subject, my proa will have a single 5hp Yamaha (bought on e-bay for under £100) but it will be only used for tight manoeuvring in channels etc and keeping me off the rocks in an emergency. Rest of the time, its sail only. No wind? – Just relax – you’re on a world cruise aren’t you? ;)

    Just a humble opinion as I’m sure you’ll appreciate, but do keep us posted on your progress.

    Best!
     
  6. Guest625101138

    Guest625101138 Previous Member

    Electric power is more expensive but you can use it to generate as well. All works well for total independence if you have a few solar panels, some decent batteries, a small wind generator and a small electric outboard as a turning thruster.

    So think in terms of the whole boat system. If you can avoid liquid hysrocarbons it has to be an advantage. Even use microwave heating rather than hydrocarbon. All renewable energy.

    You will have batteries anyhow so why not make a bit more use of them. Are you going to pull start the outboard?

    How big is the boat - you might get away with trolling motors swinging a decent prop.

    I can pull 200lbf with pedal power so no issue with thrust if the prop is sized right.

    Rick W.
     

  7. garydierking
    Joined: Sep 2004
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    Location: New Zealand

    garydierking Senior Member

    Proa power

    I use a single outboard on a vertically pivoting sled type mount about 1/3 of the way from the end of the hull on my 31' proa. There is no need to have the outboard turn 180 degrees. You always just power in the same direction. With a bit of forethought, this has never really been a problem or inconvenience.
    Mounting the outboard amidships helps to keep the prop in the water when it's rough, but having it further aft does allow you to steer with it.
    http://homepages.paradise.net.nz/garyd/out2.jpg
    http://video.yahoo.com/video/play?vid=239054

    Gary
     
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