Pontoon Boat & Deck Boat Forum

Just pondering while having a beer. I keep reading that there is a point where adding more horsepower doesn't give much more speed. Assuming I had a magical boat that could hold up any size motor the same as my little 60hp. What speed increase would my old 20 foot pontoon get with the Seven Marine 627HP outboard?

I don't know if there is a way to measure the speed of a 620 hp ripping through the floor and your ass on the way out the front

dunno--but the pontoon speed record is 114 mph.. Powered by 900 hp- 3 300hp Mercs

https://www.youtube.com/watch?v=QUAJRv27r-0

It looks like the Seven Marine 627 uses a 36 pitch prop. If my math is correct, that translates to about 190 mph at 100% efficiency. Obviously 100% efficiency isn't possible. If your magical boat hull was somehow as high as 50% efficient, you could be around 95 MPH.

That sort of makes sense considiering the 114 mph record referenced in the link above.

Good question but I think just floating the 627 h.p. would max out the old girl lol. I got to drive a Bennington with twin 300's last fall. Obviously it's a big boat but I was disappointed with the speed I saw. It was just a test drive so couldn't get carried away but I expect more than 50 mph with that kind of h.p. That said being 10' wide it catches a lot of wind!!!

I'm thinking that with enough horsepower, you approach single point contact: The boat is flying above the water with little more than the prop in the water. The problems become aerodynamic control. The "magic" is not horsepower - it's maintaining level flight control.

So....... 200 MPH to 300 MPH like a drag boat?