Weird question but how does pounds thrust convert into HP? I've got a delaminated Triton hull that I've parted out and am going to throw a kicker motor on and cruise the local bay. I know how "quickly" it moved with my Fortrex 112 so trying to get a reference point.

550 ft lbs of thrust is one horsepower

http://www.kylesconverter.com/power/horsepower-to-foot--pounds--force-per-second

There is no hard and fast correlation between the two but here ya go.

Sure you don't mean 55 lbs. thrust?

No, it is 550 ft-pds. per second. So, horsepower measures "work" where thrust only measures a static force . . . like someone leaning against a wall.

I haven't looked at the various converters but one HP = 735 watts. You can compare that to the wattage off numbers provided by Minn Kota and others to see what various sized trolling motors pull.

If you are just trying to figure out max speed, most TMs properly sized for a boat are designed to push around at about 5 mph I think.

Brad

Originally Posted By: Brad R

Originally Posted By: fouzman

Originally Posted By: Fish Killer

550 ft lbs of thrust is one horsepower

Sure you don't mean 55 lbs. thrust?

No, it is 550 ft-pds. per second. So, horsepower measures "work" where thrust only measures a static force . . . like someone leaning against a wall.

I haven't looked at the various converters but one HP = 735 watts. You can compare that to the wattage off numbers provided by Minn Kota and others to see what various sized trolling motors pull.

If you are just trying to figure out max speed, most TMs properly sized for a boat are designed to push around at about 5 mph I think.

Brad

5mph with an electric trolling motor? Dang you'd have to turn the thrust down in a no wake zone. 2.5-3 mph is more the norm.

Haha....I have pretty big trolling motor on a 16ft boat. It's an 80lb Ultrex. Two group 31 bluetops. On a good day, at max thrust, the boat manages 2.8mph....gps of course.

Yeah, I've never seen a trolling motor do 5 mph. I'm about 2 with 80# on a 17.5'. With a 101 on it I was about 2.4.

Something in the 2hp range will be much faster than your trolling motor

I have 2 / 80 lb thrust engine mounted Mk. They push my wellcraft up to 4 mph on gps.

I think that is likely correct, that my 5 mph stat is too high, that it would be tough to achieve 5 mph in a larger boat.

TMs are generally designed to get up to their slow speeds fast at the expense of top end speed.

Back on HP calcs: It doesn't matter how those three inputs are juggled. It takes 1 HP to lift 550 lbs. one foot over one second . . . and also 55 lbs. 10 feet over one second.

Brad