What a great and rare find.
I'm wondering if there is an apples to oranges comparison here?
Really! I don't know.
But there is a differnce between a standard prop and a high thrust prop.
Also that lower units can be standard or more robust. Is this important?
I understand that our boats are small enough to use a standard OB.
Was this taken into account? Is it important?
Certain that a 2stroke has MORE vibration than a 4stroke. Right?
google> prop size for sailboat outboard
boat design forums
The thread begins with 'liz' asking what to power a 24' 6000LB disp
with a 9.9 4stroke long shaft Yamaha behind the boat's rudder. [Could be an Alberg....]
last poster on thread, alan white:
"Your ratio is 2.92 : 1\The engine RPM is about 5500
Your motor appears to take a max diameter of 10" or so.
The most efficient prop would be too large to fit as a three blade,
so a four blade is recpmmended.
The recommended pitch is 8.5."
He's talking about a Yamaha 9.9 here, not the one you found, Craig.
A decade ago and still unused, I choose an 8HP Yamaha (said to be a choked down 9.9) that weighs in at 110LBS.
That is utterly rediculous, and it is utterly rediculous I customed litlgull's rear end to fit this monster. I know I will want and NEED a motor HALF the weight.
SOON I will also be looking for a 2-stroke, when I finally get on the boat.
We pointed this out befor:
If you can't get the 4stroke to run, it has to go back to the dealer.
With a 2stroke, you can do regular maintenance and tinker to keep it going.
And a 6 or even 8HP 2stroke won't require a crane to lift it out of the well.
Some people have all the luck!
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