Props

[Bricky]

Wondering if someone may be able to help.
We have a Seawind 1000 2003, which the previous owner who bought the boat new took the option of Honda 15hp.
We are about to put on 2 new Honda 20hp as Honda dont make the 15 in extra long shaft any more.
The 15hp motors have 10 x 7 5/8 pitch props which push the boat with ease.
Would the extra hp motors be ok with the standard 9 1/4 x 10 props or am I dreaming...which I think I am.
I know its a huge jump but just thinking the extra hp may be able to do it.
If not I can always swap the props from the old motors.
Cheers

[zedpassway]

Originally Posted by Bricky

Would the extra hp motors be ok with the standard 9 1/4 x 10 props or am I dreaming...which I think I am.

You should check to see what the maximum HP your manufacturer recommends. If you get into an accident which involves your use of the engine, and you put an engine on that is larger than what is recommended for your boat, your insurance may refuse to pay. This would be awful if you plowed into a 2 million dollar Hinckley motor yacht.

My little sailboat is recommended for a maximum of 6 HP. My 6 HP tohatsu SailPro moves her along at almost hull speed easily even if I am pushing against the tide, the wind, AND pulling a 10 foot dinghy. More HP wouldn't make her go any faster, since it does all that at 3/8 throttle.

[donradcliffe]

The extra hp may be able to do what??

Why are you replacing the 15 hp motors??

When you bought the new motors, did you have a discussion with the seller about the maximum speed you expected to run at and which optional props were available for those motors??

Where there any other props available for that engine??

[Bricky]

was very happy with the 15hp but they are getting a bit tired and as i said honda dont do them in an extra long shaft on the 15 any more. 20 hp is physically the same motor.
I can put the props from the old motor which will make it identical to what i have

[zedpassway]

Originally Posted by Bricky

... Honda dont make the 15 in extra long shaft any more.

The extra long shaft is worthwhile. I had problem when two people were on the bow with the stern rising with normal 20 incher. The 25 incher on the Tohatsue is way way lower: no issues with getting the impeller out of the water at all.

[zedpassway]

Originally Posted by Bricky

I was very happy with the 15hp, but they are getting a bit tired and as I said honda doesn't do them in an extra long shaft on the 15 any more. 20 hp is physically the same motor.
I can put the props from the old motor which will make it identical to what I have now.

I hate it when they rebadge the same motor with a bigger carb on it and call it more HP. My motor comes in three sizes 4, 5, and 6. Its the same engine. I took the biggest one that was allowed for my boat---might as well, they all sip the gas the same. Mine just revs higher. So its a toss up whether I can actually use the extra horsepower since the revs are above the torque peak which is essentially the same for all three. And since 3/8 throttle drive to hull speed, its all a wash anyways.