Honda 2 HP is air-cooled
So it is more noisy than a water-cooled 2-cycle motor, especially on high RPM.
canoes & motor
I use a 3.5 hp motor on 16-6 square back canoe. With a full load (abt 600 lbs) it will move along at about 7.5 mph but it pushes a lot of water. I can double the gas mileage by throttling back to about 4.5 mph which goes to the discussion on hull speed. Throttling back keeps the noise level reasonable although a trolling motor is the best choice. I have a 30lb trolling motor and on the same canoe I can go 4 mph without a load. I believe adding lbs of thrust will not necessarily increase speed significantly. You need to change the prop pitch. Trolling motors with larger thrusts are designed to move heavy boats slowly and this is not the same as a small boat quickly. Its the difference between a window fan and a whole-house fan.
Only 3 and half years late
I would imagine that the reason you can’t go any faster than 15mph is because the water starts ‘sticking’ to the hull at higher speeds and is being ‘pumped’ round the curvature, thus sucking the hull down into the water. Sharp chines (fully optimised in a transom) allow the water to flow cleanly off the hull. I’m amazed that a double ender planes at all - I expect the reason that they will with only 1 person in is because the boat is sat so high in the water that the lovely curvy chines at the back are barely in the water and don’t tempt the water to stick to (i.e. flow round) the hull, like happens in displacement hulls.
1970 Quachita 17’ X 1954 Johnson
Stern croped and transom added.You hit the speed right on. Loaded with 610 pounds onboard, GPS tested @ 6 miles an hr. Have a great day, Wes
Motor Ratings
You know I was recently reading ratings for the smaller 14+ ft square back canoe. I think it was coleman and rated for a 4 HP motor. More than one person mentioned having the canoe sink using the full 4 HP. Just something to be cautious about.