How much more speed will I get

[kentuckylakeguy]

I have a 20 parti kraft pontoon 2 tubes with a 40hp omc.. It runs around 14-15 mph (just guessing) I am wanting to put a 75 hp on it.. How much more speed will I get out of it with the 75hp??

 

[Big Bubba]

Re: How much more speed will I get

Kentucklakeguy,
Good day to you. I have a 20 foot Pontoon boat with a 70 horsepower Johnson, 1983 year that pushes my pontoon at 23 mph WOT and it has a 14 X 15 Pontoon propeller but that is without power tilt and trim. This year I bought one of Ebay and installed a complete power tilt and trim unit and can't wait to try it out to see how it works. I should be able to get more MPH faster out of her because with the manual tilt/trim I had the motor basically as far down as it could go know I can adjust it while I am underway and see if it does pick up.

 

[5150abf]

Re: How much more speed will I get

Kentuckylake, first of all make sure your motor pan is rated for that horspower, I'm sure you wouldn't want to fish your new motor out of the lake.

As to speed, you should get more but probably not as much as you think, it takes alot of power to push a toon, they are very inefficient hulls as they push through the water rather than ride on top of it, that is why they ride so nice in chop is the wave peircing hulls.

Twice the power doesn't equal twice the speed, this a total geuss but I would say with the 75 you would pick up 4-6 mph.

And tilt trim doesn't have the same effect on a toon as a mono hull boat, it does help but I don't think you will see a huge gain in speed.

 

[Silvertip]

Re: How much more speed will I get

One thing is for certain -- you will pick up a couple miles per hour and burn a great deal more fuel.

 

[bobhsml]

Re: How much more speed will I get

Rule of thumb 2 mph per 10 extra hp

 

[steelespike]

Re: How much more speed will I get

As suggested the 75 would be in the 20-23 mph range.Your 40 probably burns about 4 gph(gallons per hour) at wot (wide open throttle).The 75
about 7.5 gph.(10% of the hp.Of course you can throttle back to the 40s speed and get better gph and the motor will be loafing.