4stroke for square back canoe advice


i have an Esquif Heron (14 feet, about 38 inches wide, very nice canoe) with a square back for a motor. i use a Minn Kota with 30lbs thrust. it works well, trolls beautifully and is very quiet. moves me about 7 knots at it’s fastest on a calm lake. i want to go much faster at times on bigger lakes but wouldn’t you know it, stores just don’t demo 3hp motors to guys like me for fun. so either plop down a thousand bucks and take my chances, or somehow find out an approximate speed that a 3/3.5 motor will move my canoe. any thoughts out there? thanks.

I’ll tell you.
If I get a chance to take my Heron (same boat, but 17’), I’ll tell you what a 2.5HP Mercury 4 stroke will make it do. I’ll tell you this, when I tested my boat against current with a 55 ft/lbs thrust trolling motor and with the 2.5 HP Mercury, the gas motor was much, much faster.

I haven’t taken it to a lake. It’s no speed demon, I’ll guarantee, but I get about 4mph up current with two people in the boat in an area with fairly strong current. No lake measurements though.

  • Big D

Power canoes
It is easy to swamp a canoe with a gas motor. Traditionally small motors like 1 1/2 or 2 hp have used, like a Seagull. For serious motoring consider lashing two boats side by side about 6 feet apart. That is the way Native Alaskan travel up and down places like the Yukon River.

In the 1980’s, I had a 1.2 hp
Aquabug on a sidemount on my 17’ Grumman Canoe. It was very reliable, lightweight, and efficient. On flat water it might reach 8 mph, and wasn’t tippy even when turning at speed. I often wished I had a few more hp though, because with a good headwind, it had trouble keeping up. A 3 hp would have been perfect, if it wasn’t too heavy (they were 2-strokes). Unfortunately, the company went out of business in the late 1980’s. I would try for a 3 hp, if you can find one under 25#, but even that will limit your freeboard.

Evinrude Lightwin
Skip the 4 stroke and find an old Evinrude Lightwin for $ 150.00 - $ 200.00. They are all over Craigslist, 3.3HP and 33 pounds. Yes they are 50 year old technology, that’s why they still work!


I like your post. Small investment for big return. Two cycle engines are dependable if you take care of them.

Consider this…
My 20’ sailboat weighs 1500 lbs - and I motor it around with a 3.5hp outboard. Probably only goes around 5mph max - but I have a high-torque prop on it that limits it’s top speed. You figure the math (it’s over my head).

The Heron should do fine with the smallest gas engine you can get. Probably still will go fast enough to get in trouble.

I got a Honda 2.3 hp last year
and use it on my 17" square stern aluminum Grumman canoe. Last trip we probably had the canoe loaded at it’s weight limit and still it was able to go between 6 to 7 mph. With just two people and no load I have been able to get it up to about 10mph. What I really like about the Honda 2.3 hp motor is that it only weighs 27 lbs empty.

hp on a canoe
People seem to forget that canoes are displacement hulls. Pushing them too hard can rip the bottom out of one. We had a fiberglass dingy when I was a kid and ripped the bottom out of it by towing it behind a powerboat. Canoes start to handle in unpredictable ways past about 5-7 knots.

2.5 Suzuki 4 stroke
I have a 100 pound plastic square stern Old Town with a 2.5 Suzuki. It’s not fast, but it will go all over the lake at half throttle on a sip or two of fuel. Beats the heck out of trying to beat the thunderstorm back to the dock with just a trolling motor.

I’d like to see some data on that.
The QE II also has a displacement hull and it’s got oodles of power.

  • Big D

Big D,

Speed is a function of waterline length. A ship that is over 1000 feet long is a different kettle of fish entirely even with a displacement hull compared to a boat that is 15 feet.

Give it enough power to plane…
…and the QEII would probably self-destruct too.

So are you saying that if you overpower a boat that bad things can happen to it? That seems pretty obvious.

V-bottom and semi-V fishing boats are displacement hulls, many are 14’ and 15’ long similar to canoes, and they get engines that are far more powerful than canoes will take from a weight perspective yet their hulls stay intact unless the driver hits a ledge while under power.

Don’t overpower any craft - got it. Good advice.

Power causes the bottoms to rip out of displacement hulls - having a hard time believing it given the number of powered canoes, v-bottom boats, and other displacement hulled boats of roughly the same size that are operated with intact hulls on a daily basis.

  • Big D

hull shape

– Last Updated: Nov-07-13 1:21 PM EST –

V bottom and semi-v fishing boats are planing hulls.

The dinghy that was wrecked was being towed by a much larger powerboat.

manufactureres know
Call the canoe manufacturer Im sure they tested it and have the data.

You don’t plane displacement hulls. But there’s nothing wrong with pushing them with power.

Given enough power…
…anything will plane. Whether it survives the trip or not is another matter.

But we were talking about canoes. I think the most important point is to not unbalance or overpower the hull. Pretty easy to do in a canoe.

Canoes will get up on plane just fine, and I’ve seen it done lots of times. Canoes will plane just about as easily as small semi-V fishing boats, and the only reason most people haven’t seen it done is because most people haven’t seen a 5- or 7-HP motor powering one. The bottom of any square-back canoe is just as flat or flatter than that of a small rowboat style of fishing boat, and they WILL plane if pushed by a slightly larger motor than what most people use. The idea that you will “rip the bottom out of it” if you make it plane is crazy. On the other hand, having too much power can result in a real risk of flipping during sharp turns.

That’s right

– Last Updated: Dec-28-13 10:41 PM EST –

One of the people in this conversation couldn't keep track of which reply button to use, which caused the conversation to split into two parts. I found this separate part after posting above.

Yes, I used to see aluminum square-back canoes up on plane when powered by a gas outboard lots of times. Think about it. The bottom of such a canoe is quite flat, just like the bottom of the rear half of a semi-V fishing boat, and the draft of such a boat is 3 inches or less with a normal load onboard. If a 12-foot or 14-foot semi-V gets up on plane when powered by 5 horsepower or more (5 HP is more than enough if the load in the boat is light), why should it surprise anyone that a rather flat-bottomed canoe that already has very shallow draft will do the same? What's more, there are plenty of small aluminum fishing boats able to handle much larger motors, but the gauge of aluminum is about the same, and the degree of reinforcement of the stern in pretty minimal (just one very short diagonal strut going from transom to floor, or even nothing more than a piece of plywood across the width of the transom). If there was much risk that the boat would come apart, you'd see all sorts of extra reinforcement on them. Don't forget all those wooden rowboats of years ago made from 1/4-inch plywood, and they didn't have a habit of coming apart when up on plane either.

The danger with a canoe is that it will simply roll over if strong power is applied while the motor is turned very sharply to one side. The point of power application is well below the bottom of the hull, and when turned very sharply to the side, the shaft of the motor provides a lever arm that will simply twist the whole boat, possibly flipping it. The back end of a row-boat style of fishing boat will usually side-skid in that situation, and the boat just turns really sharply. Since it lacks the extra width and stability of a traditional small boat, the canoe is much more likely to flip if much power is applied by the motor when sharply turned.