Tri powered boat dilemma

Dale05Dale05 Club Members Posts: 2
I'm building a boat with three brushless motors, my dilemma is,do I need to put a left and right prop on the appropriate sides and if so what do I use on the middle shaft.Or can I use three props the same.Shaft size's are 4mm and I have room for props from 28mm to 34mm. Hope someone can help me, this is the first boat I've attempted to build.



  • swervynswervyn Club Members Posts: 1,313
    good question! I guess with 3 props running the same way you are going to end up with a huge amount of torque from the props and find it near impossible to keep in a straight line. Plus you will need a huge servo to steer it. How are you going to steer it? 1 servo linked to 3 drives?

    I reckon a bit of trial and error involved. Get yourself left and right props and see what works best for the centre, whatever puts the least amount of stress on the steering servo. Just get cheap plastic props for starters until you work out the best setup.

    Either that or use 4 motors lol
  • Dale05Dale05 Club Members Posts: 2
    Thanks for your reply,I'm using a 3kg servo linked to the three rudders. I'll take your advice on board and will let you know how it goes. If I had enough room I'd try 4 motors. Maybe on my next build. Lol.
  • SootySooty Christchurch NZClub Members Posts: 6,110 ✭✭✭
    Are you intending to create mixes for the ESCs with your rudder so that you can use power steering?

    Single prop boats just use a trim tab to counter torque so set you center prop up with a trim tab and use counter rotating props on the outside.
  • canabuscanabus Club Members Posts: 39

    ******* have 4mm props CNC left and rights.
    Some boats are OK with three the same way and others two one way and one the other.


  • neilbenineilbeni Club Members Posts: 4

    Lol only conclusion for me to balance your problem is. Always run props opposite direction and as a third place a jet boat setup in the middle..

  • Stephen WrigleyStephen Wrigley Club Members Posts: 1

    Hi, I have run 2 outboard motors both left turn propeller on a v hull, I made a linkage so both were steered together from the centre, they ran great very easy to keep it in a straight line it did steer better very slightly one way hardly noticeable, if I were to run 3 props then probably best to run R & L outside middle prop anyway you like, try steering by two rudders one on each side, hope this helps you out, Stephen.

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