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In article ,
says...
Hi All,

I own a 3 meter Hypalon (rubber) boat, on which a '76 Johnson seahorse
6hp is mounted.

Whem i'm the only one in the boat, and I accelerate, the front of the
boat rises very high, and no speed is gained. When I move myself to
the front and accelerate, The nose rises, lowers, speed is gained, and
the boat is planing. As soon as I move myself to the back, the nose
rises, and I must to be carefull not to take off

When there are two people in the boat, the nose wants to rise, but the
engine lacks the power to overcome the drag created by the extra
weight of my passenger.

My outboard is in (nearly) mint condition, and the enginepart is not
definately not worn out. I had it recently checked.

I now wonder: would a modern 4 stroke 6hp do the trick for two people
in the boat? I think that "my" 6hp is measured on the cranckshaft,
wheras (for example) a modern mercury 6hp is measured at the prop. I
also think that modern engines just perform better. Am I right?

I do know that for example a 15 hp engine would do the trick easily,
but that is not an option, for I deflate the boat after every trip,
and I need to take the outboard on and off whilst the boat is in the
water. Since i'm not the incredible Hulk, a max weight of about 30kg
seems enough for me

Please advice!!

Thanks,

Ronald

Hi Ronald

Your mounting bracket should have some holes that allow you to adjust
the angle of the motor. The angle of the prop to the bottom of the boat
will have an effect on how the boat rides.

If you tuck the motor in it will force your bow down since part of the
energy from the prop is trying to push the stern of the boat up and you
should be able to get up on a plane without having to move about the
boat.

If you have two people in the boat bring the motor out and some of the
prop's force will be pushing the stern bow down forcing the bow up, and,
again, you should be able to achieve a plane.

You'll probably have to trial and error the settings until you find one
that works for you and the boat and it would probably be a good idea to
have any passenger sit in the middle seat of the boat and in a position
where they counter act your weight.

While a bigger motor will move you along more quickly and, to some
extent, more efficiently, no matter what the horsepower of the engine
these factors come into play and you will still have to address them.

Put a larger motor on the boat and tuck it in too far and the bow will
try even harder to bulldoze, bring it out to far and you'll have to
stand up to see over the bow.

Good luck

--
Mike G.
Heirloom Woods

www.heirloom-woods.net