size of motor for canoe

I have an Oldtowner Discovery 164 canoe and want to put a motor on it. They have a 1.8HP 30LB thrust motor. Does anyone know how much speed this will give me? The canoe will handle up to a 4HP motor. Should I step up? I want to go a little faster than a fast paddling duo!

Does not take much!
I have a 15’ aluminum Grumman canoe that i have a Minnkota 28 lb trolling motor on and it is more than enough to push it around. I use it for fishing and am totally happy. I can fish all day long and never come close to running out of a charge.

on my 16 ft OT, with a 2HP Honda and two 190 lb adults, at full throttle the roll in the wake disappears, an indication that it is planing. I would guess this is at around 8 or 10 MPH. I don’t use the motor anywhere near as much as I thought I would, but occasionally comes in handy motoring upstream to paddle back down when I can’t arrange a shuttle.

trolling motor
Would a 50Lb thrust motor move my canoe faster than a 30Lb would? Or would it just be easier to get the canoe going?

couple of 150’s?

what afolpe said, More power Grunt grunt!!!

Who are “they” Dallas?

– Last Updated: Mar-11-05 10:32 AM EST –

and yes, 50 pounds would push more than 30. I use a 36 # Minn Kota on my Penobscot 16. Works well.
Speed? Only canoe speed I've measured under power (so far) was one of our camping trips across a lake where my canoe was the freighter. Including me it was carrying roughly 500 pounds and my GPS showed 3 to 3.5 mph with a 70 amphour Walmart 12 vdc marine battery in good condition with my Minn Kota 36 # thrust at speed 5 (highest setting) into a approximate 3 to 5 knot cross-to-headwind condition if I recall correctly.
JEM's remarks below mine are excellent reference for these hulls. A wide squareback canoe could exceed hull speed if you get the transom down and the hull onto it's wave and may possibly plane if you kept your weight "shiftable" (or had about 8+ horsepower) but a "double-ender" (canoe hull for example) is meant for efficient hull speed. Not excess of hull speed.

keep in mind…
that canoes, are “displacement hulls”.

The GENERAL rule for displacement hull speed is:

Maximum Hull Speed (in knots)= 1.34 * sqaure root LWL. One knot is about 1.1 miles per hour

What that translates into is you take the square root of the length of the waterline, and multiply by 1.34, that’s the fastest you can expect to go under power. So a hull with a 15’ waterline can go about 5.2 knots (5.7 mph).

Now you have to consider how much weight you’re trying to move. It’ll take longer to get more weight up to speed. But even if you have a high HP motor, after you get to the max hull speed, giving it more power will only dig you into the water more. You won’t go faster.

On a canoe, I say go for the smallest motor you can to get you at a decent speed. What a “decent” speed is your choice. A smaller motor will last longer with regard to battery charge or gas usage.

This is a general rule. You can tweak the numbers and make arguments for different shaped hull. The thing to keep in mind is that a canoe is not a power boat. It’s a cruiser

Hope that helps!

Thanks for your help guys!!!

Yeah, you can plane a double ender but
both of you had better be sitting in the bottom of the boat, not on the seats. And usually, enough power to get you on plane will splash a lot of water in the boat. The noise is the worst part, I thought a Honda would be quieter than it turned out.

Hull speed
Paraphrasing from the book on naval architecure used at the Naval Academy:

Hull speed is related to “wave making resistance”.

Wave making resistance is one of several components of total resistance.

The total resistance increases slightly below hull speed, then decreases slightly above hull speed, then decreases as the hull starts to plane.

Hull speed is NOT the maximum speed that a boat can achieve.

Hull speed has no meaning for a motor-driven ships because if enough power is used this speed can easily be exceeded.

17’ Grumman Standard and 3 HP Outboard
At about half throttle my canoe planes with one person on board. I haven’t measured the speed with my GPS but, I would approximate it at about 15 MPH. Giving it additional throttle beyond the half way point, with only one person on board, provides little additional speed and causes the stern to squat down more. I have a sling seat (designed for a 3rd passenger) that I use to position my weight just forward of the rear thwart. I use an extension to the motor’s handle for steering. When carrying heavy loads and two people, the boat doesn’t plane at full throttle. The full throttle is desirable for pushing this load up stream in heavy river currents.

A useful option for canoe motoring is a set of outriggers. I dumped the canoe once using the motor when I accidentally hit the throttle with the motor turned perpendicular to the boat. I can still paddle with the outriggers when I have the motor turned off for fishing.

My motor is noisy and I can smell the exhaust fumes. I infrequently use it but it is nice option for activities like soloing up river.

Which Outriggers did you buy?

motor tilt
If the stern squats when you are planing and apply more power, you may want to try setting the motor angle so that the lower unit is further forward.

Mid-American Boat & Sport
They are very durable foam filled polyethelene shelled floats combined with heavy aluminum square tubing. I purchased the outrigger in 1984. They were manufactured in Fresno, CA and the phone number, when I bought them, was (209) 255-3507. I just Googled the company and couldn’t find a Web URL to provide you.

Similar to these

3.6 hp on a canoe
20 or so years ago (has it been that long?!), I used a 3.6 HP Mercury on both a 17’ Coleman and a 15’ Coleman square stern. How’s that for combining the worst ‘sins’ of paddling in one sentence? :slight_smile:

Anyway, the 3.6 was fine on the square stern but a bit much on the canoe, largely because it was mounted on an adapter that put the motor on one side of the boat. The resulting imbalance made for weird handling, especially at slow speeds or when turning.

I still have that motor but never use it. Guess I ought to sell it some day…

Thanks Richard. What size motor
please? Weight of your outboard?

thanks again.

Suzsuki 2 HP @ 26 lbs
It is amazing how fast an unloaded 17 ft double end canoe will go with a 2 hp motor. I have to sit forward of the rear seat in order to plane. Initially I used a section of PVC pipe as the steering handle and when I needed to cut the throttle I would just move back to the motor and manually turn the throttle off. Remember I have pontoons and so I don’t have to worry about the canoe tipping. Later on I purchased a commercial telescoping motor handle and a throttle extension lever from Cabelas.

The vast majority of the time I paddle without a motor or the pontoons. When salmon season starts and river is swollen it is nice to safely zip up stream (using a motor and pontoons) and then drift back to my campsite each day. I sometimes think of this rig as a “poor man’s jet boat” that has the benefit of being able to be paddled if the motor stops working.

…since this sounds like the right crew to ask. Has anyone used a small, golf cart/wheelchair type battery in their canoe? I occasionally like to use my

trolling motor, but only have a regular rechargable battery, which probably outweighs the canoe & motor combined. I assume I’d need enough reserve for 2-4 hourw with a lightly-laden 14’ solo.