Canoe outboard and anti-ventilation question

[thegopher]

Hello i have a canoe that i am mounting a 2hp outboard on. i am building a bracket for the motor that will allow it to be mounted on the stern even though it is a double ended canoe. my question is where should i mount it in relation to the anti ventilation plate. everything else i have read relates the plate to the bottom of the hull, this is fine for a regulat boat but with a canoe there is no clear bottom of the hull except in the middle of the boat. is there a rule of thumb for how the deep in the water the plate should be? thanks, Dan.

 

[tashasdaddy]

Re: Canoe outboard and anti-ventilation question

Dan, welcome to iboats. if possible, make the transom bracket so it can be adjusted. even if just by moving the piece of plywood up and down, by removing the mounting bolts. the motor has to be deep enough when running to pick up cooling water. moving it up will increase speed. you really want the AV plate just above the water when wot.

this is the mount for my inflatable as you can see it is adjustable. i use a 3 hp on it.

 

[Drowned Rat]

Re: Canoe outboard and anti-ventilation question

Remember that when you're underway in your canoe with the motor hanging off the gunwhale, it offsets your center of gravity. I don't think you can mount it too high, as the motor wants to dip into the water on the side it's on. Mount the transom bracket on a block of wood that sits about 4 inches above the gunwhale and you'll be fine. Make sure the bracket sticks out far enough so when you turn, the prop doesn't hit the hull or even come close. That's a small detail that can be overlooked when building those things.

 

[thegopher]

Re: Canoe outboard and anti-ventilation question

thanks for the replies, i won't be mounting off to the side using the gunwal though. even though it is a double ended canoe and am designing a bracket that will mount the canoe directly off the back of the canoe like a regular transom. this weekend i am going to put the canoe in the water and take some measurements like the distance from the topmost part of the stern and the water, hopefully this will give me a better idea of how high to make the mounting plate. thanks, Dan.

 

[BF]

Re: Canoe outboard and anti-ventilation question

Hi,

I have a removable, "no holes" motor mount that is quite slick for my canoe. It doesn't go right on the stern, but rather attaches to the cross brace just behind the rear seat and portrudes enough on the port side to mount the motor on. I think it would be a PITA to have the motor right on the stern if that is what you are intending. The 2 hp's need to be turned 180 degrees for reverse, and you'd have to reach way back to adjust the throttle... the handle's probably too short too.

What ever mount you make up, remember that the motor mount plate needs some angle on it. If it was 90 degrees to the surface of the water, your motor would end up trimmed up when mounted.

As for how it will handle... remember that the motor pushes from the prop. Imagine what it would be like if you mounted a 2x4 sticking down into the water (like where the prop would be). Now if someone grabbed the bottom of the 2x4 and either pushed or pulled it to the side. The effect is that it acts like a lever that will want to make the canoe rotate down it's long axis (capsize). This is exactly the force that the prop will exert when you turn the motor. The sharper the turn and more force the motor exerts (faster) the more it will try and capsize you. That's why canoes can fly in a straight line, and capsize when you turn them. Canoes aren't that stable, but the real problem is the motor acting like a lever to rotate (capsize) the boat. If you make it a habit to slow down for turns, and only try and rotate the motor (for reverse) at idle speeds.. then your odds of flipping go down a lot.

good luck!