Stingray or 4 blade prop?

Hello,

I bought a new G3 1652 with a Yamaha 4 stroke 25 hp tiller outboard. My daughter and I took it out today and I never could get on plane. I tried the different tilt settings and as you can imagine it did best in the lowest setting. I was getting a lot of cavitation and the max speed was 9 mph according to my gps.
It has a 3 blade prop on it now. Would a 4 blade prop get me on plane and up to speed? Would a Stingray or other hydrofoil be worth trying?

The current prop is a 9 1/2 X 10 1/2 three blade OEM that came stock.

It looks like the cavitation plate is about 2 1/2 - 3" above the bottom of the boat.

jmontgomery said:

It looks like the cavitation plate is about 2 1/2 - 3" above the bottom of the boat.

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Well then there's your problem ... you have a short-shaft motor installed on a long-shaft hull and the transom is blocking the free uninterrupted flow of water to the prop ... so you have lost a ton of forward thrust.

Less cutting down the transom to get that plate about equal +/- from the bottom of the boat, or adding a jackplate to lower the OB ... then the only other option would be to replace that motor with a long shaft configuration (albeit some OBs have an adaptor kit to make into a LS version).

Looks like a trip to the dealer tomorrow.

I would not cut the transom.

jy951 said:

I would not cut the transom.

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Neither would I.



FYI.... it is an anti-ventilation plate, cavitation is something completely different.

SumDumGuy said:

jy951 said:

I would not cut the transom.

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Neither would I.

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I wouldn't either ... but it is an option ...

I think the stock prop should be something like 10 x 13. Yours seems small.

You mentioned trim positions, is the motor on the lowest mount hole?

The dealer swapped out my motor with a long shaft. This new motor has hydro assist and he paid for my registration and another year on the warranty.

jy951 said:

I think the stock prop should be something like 10 x 13. Yours seems small.

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9 7/8 diameter and 10 1/2" pitch is the factory installed prop that came on all of the current Yamaha 4 stroke 25's, since 1998/9. And honestly, it's a pretty good prop that works for "most" applications. Might be a tad on the conservative side for the typical duck boat like what we sell mostly, but for the bigger 16' and up boats, should get about 26 mph at 6000-6050 RPM. Assuming the hull is decent.

The dealer did you right! You have a good dealer.

Would a 4 blade prop work better?

It might. It'll slow you down a little (top speed will suffer) but it helps get on plane, and runs smoother. If you do go with a 4 blade, you'll want a 9 or 10 pitch. Probably a 9. Usually when switching to a 4 blade, you'll drop an inch or two in pitch to make up for the extra blade. I ran a 10" and I loved it. Went from 11 1/4" pitch to a 10" and lost about 1.5 mph top speed, but it was on plane instantly and stayed on plane clear down to around 3000 RPM. But mine's a lighter smaller boat.