can i get more speed from a different prop

I have 05 24ft pontoon with a 05 50hp yamaha wot is 5500 and my speed is 15.8 mph on the gps ,, can i get a little more speed from my motor with a different prop or do i have to bite the bullet and buy a bigger motor boat is rated up to a 115 ,,but this set up was very common on the sales floor ,,the salesman said that setup is sold to plenty of marinas that rent pontoons ,,thanks in advance ,,

Re: can i get more speed from a different prop

Not from a 50 hp motor. If you want speed you need a "tri toon"(a pontoon with three logs under it). A two log pontoon will never likely produce enough speed to satisfy you, no matter how much horse power you hang on the back. It'll go a few mph faster and burn twice as much gas.

Re: can i get more speed from a different prop

jestor68 said:

Not from a 50 hp motor. If you want speed you need a "tri toon"(a pontoon with three logs under it). A two log pontoon will never likely produce enough speed to satisfy you, no matter how much horse power you hang on the back. It'll go a few mph faster and burn twice as much gas.

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well thanks for telling me what a tritoon is ,,but thats not what i asked ,, I knew when i purchased the pontoon it wasnt for speed ,,thats why I also have a W.A.C.,,what I am asking is can i possibly get a LITTLE more speed from a different prop,,not looking to do 40mph in a pontoon maybe 22 to 25mph,,without having to drop 9k on a new 115 yamaha

Re: can i get more speed from a different prop

Ill do a little checking In the mean time give us the info from the stickys at the top of the prop forum.
I think you can do better. Is your speed with a light load? Prop size should be under the prop nut.

Re: can i get more speed from a different prop

steelespike said:

Ill do a little checking In the mean time give us the info from the stickys at the top of the prop forum.
I think you can do better. Is your speed with a light load? Prop size should be under the prop nut.

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thanks man ,, yes really light load me alone and 26g of gas ,, i will re read the sticky notes and when i get home i will find the prop size ,,

Re: can i get more speed from a different prop

After a little research;
I think 22 would really be a stretch but 18-20 may be possible.

Re: can i get more speed from a different prop

Yamaha makes a special "pontoon series" of SS 3 blade props, and special "dual thrust" aluminum props that have large blades to produce more thrust than a standard prop. They fit the T-50; not the F-50.

You'll need to visit your Yamaha dealer to check on them, as they are only sold through an authorized dealer.

Depending on what you're running now(5500 rpm with a light load), one those specialty props might get you a couple more mph. Or reducing pitch by 2" might gain 400 rpm and a little speed.

If you visit the Yamaha web site and view the performance tests of pontoon boats powered by 50 hp motors, you will see speeds of 17-18 mph on 20-22 ft boats. Some of those are using a specialty prop.

You would be ahead of the game if your motor is the T-50(larger gear case) as it would be able to make use of the specialty props.

Re: can i get more speed from a different prop

Gaining 400 rpm does not gain speed. It means the engine needs to run faster to maintain the same speed as before because the prop has less pitch and therefore moves the boat less distance with each rev. Decreased pitch results in increased speed only if the engine is over propped to begin with.

Re: can i get more speed from a different prop

Silvertip said:

Gaining 400 rpm does not gain speed. It means the engine needs to run faster to maintain the same speed as before because the prop has less pitch and therefore moves the boat less distance with each rev. Decreased pitch results in increased speed only if the engine is over propped to begin with.

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I believe I said "might" gain a little speed. With a pontoon, nothing is for certain.
But it is certainly possible to pick up a little speed by reducing pitch when your motor is not turning up to it's peek rpm.

Re: can i get more speed from a different prop

Turbo also makes a special pontoon prop.

Re: can i get more speed from a different prop

Silvertip said:

Decreased pitch results in increased speed only if the engine is over propped to begin with.

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He's only getting 5500 rpm with a light load. That indicates that he is over propped, as he needs 500 more rpm to reach the motor's peek rpm of 6000 rpm.

Re: can i get more speed from a different prop

That engine running 5500 rpm is NOT over-propped. In fact it is at the top of the recommended range which is where it should be. That engine has a 1.84 gear set so running some 5500 and 6000 rpm numbers through a prop calculator using 15% slip with 15 and 13P props shows a 2 MPH speed loss. My suggestion is to visit the Yamaha web site and check PERFORMANCE BULLETINS. Select your engine, select your boat and then check performance bulletins. They list everything you need to know and some things you don't. If they didn't test your exact boat pick one closest to it.