Bret Ludwig wrote:


JStricker wrote:
Long stroke, slow turning engines ARE still used and designed all the
time
in agricultural, industrial, and marine applications. It all depends on
where you want your peak torque at. In an aircraft engine, the best prop
efficiency trade-off is in the 2200 - 2500 rpm range and the most
efficient way to transmit power is via direct drive, hence engines are
designed for the applications in which they are used.

Where are the long stroke, slow turning gas small boat engines?

In museums. Inboards ALL use autoderivative engines and ahve for
almost 50 years

Small boat motors turn small "props" at high speeds for usually not long
periods of time. Besides cooling is usually not a problem with a large
supply of cooling fluid! ;-)
John