motor position

i agree with scaling hydrodynamics, and it's probably the better solution like you said, so i believe i will use that when i start construction

 

Then I'd suggest looking at bigger props and bigger/faster motors. An 11 ft ship weighing 100+ lbs going 15 ft/s is going to take a bit of effort, and it isn't likely to be cheap.

 

A ship this size warrants the use of some serious propulsion...perhaps even a proper electric trolling motor?

 

it might need something that big i do agree with the large amount of propulsion to get the monstrosity of a canoue moving

 

if i was to gear the motor what would be a desierable gearing for the ship?

 

Whatever works and allows your motors to run efficiently and the props to produce the desired thrust to meet your speed requirements. The answer depends on what prop and motor you end up with as what has been mentioned here probably isn't suitable to do what you want it to do. It's probably best to get building the hull and then figure hot how big a prop you can fit under it and how big a motor you can fit in it and work from there.

 

okay, thank you, i will keep that in mind when i stat building, in late May

 

what batteries would you recomend to power the ship? i read that Lipos don't like water at all, is that true?

 

If trying to keep the cost down, normal sealed lead acid batteries will work just fine. In such a large ship, weight will not be an issue. Heh.

 

like the 12 volt automatic gate opener batteries?

 

Sure. That should work. Just make sure it is a SLA and not a refillable type.

 

i had a thought could you use gas powered motors from rc planes to power your ship, i have several smaller motors that could have enough power.

 

I think the lack of proper cooling would be a problem. Also, there are many places where you cant actually use gas motors.

 

hadn't thought about cooling them, so that is out of the question, sorry trying to use what i have without having to buy a whole bunch

 

with three motors would having seperate ESC's for each motor work better or have all three motors run off one? i've read on here it's better to have redundancy.

 

Depends on the motory type. It is possible to run multiple brushed motors on one ESC. My first ship, a Richelieu, was set up that way with two motors on one 100 amp ESC. The motors were wired in parallel just in case one motor failed (which happened twice for various reasons). The key is to have an ESC with enough amp capacity to carry the load of three motors.

If going brushless, then each motor requires an ESC. It is not possible to run multiple brushless motors on one ESC.

If the ship will have turning motors (rpm difference between inside and outside props to help turning), one esc per motor is needed.

 

ok thank you, because you had sugjested to have the propeller on the inboard side of the turn reverse to help turning, so multiple ecs's will be needed, also i was thinking about having the rudder control arms crossed so that the inboard rudder turns further than the outboard rudder, hopefully helping with turning as well. how well does that work?

 

We've seen a lot of ships with differential rudder setups and most will turn as good or better than a straight setup.

 

ok, i had read that on the Bearn build and wondered if it worked, also how strong would the servo have to be to turn the rudders to move the canoe.

 

Ah, you are kinda in uncharted territory on that one. Heh. The size of the ship will most likely need something stronger than a standard sized analog servo. Hmmm ... then again, one servo per rudder may do the trick.