can i get more speed, or better mph?

[Tim K]

i have a 20' landau pontoon boat w/ a 50 hp mercury motor. i can only get about 17.5 miles per hour. will changing the prop or installing a hyrofoil give better speeds and or improved gas milage? i believe my current prop is a 12.5 by 8 pitch. or is there something else out there to achieve my goals, of more speed and better fuel economy? thanks!

 

[rickdb1boat]

Re: can i get more speed, or better mph?

17.5 MPH is about right for your set-up. What are you wide open throttle RPM's? You can put some "Tap Fins" on there, but they are quite expensive to buy and install. Or, you could add a 3rd toon, which would give you a little more lift and speed(Maybe 3 or 4 MPH.) There's always the option of a bigger motor, but even then, you will see only 5-7 MPH more, with say a 70 HP on there. Pontoons are funny that way, being displacement hulls. They don't react to HP increase like planing hull boats do. Mine does 24 MPH with my 70 HP Johnson and that's good enough for me for a toon. Here are a couple of links to some pontoon forum sites that may interest you and answer some more of your questions about what I've been talking about. <br /><br /> Tap Fins <br /><br /> Pontoon and Deckboating <br /><br /> www.mypontoon.com <br /><br /> Pontoon Boating

 

[Tim K]

Re: can i get more speed, or better mph?

rick, <br />thanks for the post. here are the answers to your questions:<br />1) at full speed the boat will run about 17.5 mph and the TAC reads at 1.0, in rougher waters the TAC got up to 1.8. the boat use to have a 70 hsp mercury and the top speed then was only about 19 mph. some friends told me my TAc should read about 4.0 to 5.0, so maybe the Ac was not hooked up propely so i will have this checked out. does this help you? if i can give you any other info, just let me know. <br />again, thank you very much for your help.<br />tim

 

[Solittle]

Re: can i get more speed, or better mph?

I agree that your tach is probably not wired or set up correctly. If you are running 17.5 mph your tach should be reading a lot more than 1800 rpm. A 20' pontoon is not going to roar down the lake with a 50 on it no matter what you do to it - - - unless you put a 100 hp along side of it.

 

[rickdb1boat]

Re: can i get more speed, or better mph?

I'm with SoLittle on the Tach. problem. Please refer to the actual Tach readings when posting.(5000 RPM's, 5500 RPM's, Ect). At the 17.5 MPH, your engine should be turning about 5500-5700 RPM's. Try to get the Tach. fixed up and we can go from there. You may want to take a look on the back of the Tach. and see if it's set on the correct pole setting. Should be a small screw that has different settings on it(4,6,8,Ect). Yours should be set on "6". Also, what year is your 50 HP motor?