The analogy with an outboard may not carry over to an inboard, but on my
sailboat
there is a distinctive improvement in performance using a 'pusher' type engine
gearing. Most outboards that do specify their use on sailboats usually have
gear
ratios 3.0 or higher. The best pusher I ever used was my British Seagull 6
bladed
prop with a gear ratio of about 4:1, and I saw pictures of this engine pushing
huge
heavy barges.

Roger Long wrote:

"sherwindu" wrote

I think your gear ratio should be closer to at least 3.0. Your
transmission

sounds like it is configured for a planing power boat.

No, that's a fairly typical reduction for a sailboat. The greater the
reduction, the larger the prop. Sailboats usually compromise
effeciency under power with smaller reduction ratios and props in
order to reduce drag under sail.

--

Roger Long