Optimal cruising RPM

[Bowdrie]

Originally Posted by Dockhead

But the king of variable pitch props is the Hundested, which has manual rather than auto pitch control. Minimum size of that one is for 150hp, so Audeamus could have a Hundested.

In days gone by they made them for smaller engines.
Back in the '70s I installed a Hundested in a Westsail 42, along with a Volvo engine, (IIRC,) the prop was ~22" diameter.
A simply marvelous piece of engineering, like a Swiss watch.
You had your choice of two different installation configurations.
For a power boat you didn't need a transmission, the pitch control would move the prop either side of flat pitch so as to provide both astern/ahead.
For a sailboat you used a transmission for reverse and the control moved the prop between feathered and a range of forward pitch.

[TeddyDiver]

Originally Posted by Bowdrie

In days gone by they made them for smaller engines.
Back in the '70s I installed a Hundested in a Westsail 42, along with a Volvo engine, (IIRC,) the prop was ~22" diameter.
A simply marvelous piece of engineering, like a Swiss watch.
You had your choice of two different installation configurations.
For a power boat you didn't need a transmission, the pitch control would move the prop either side of flat pitch so as to provide both astern/ahead.
For a sailboat you used a transmission for reverse and the control moved the prop between feathered and a range of forward pitch.

There's a couple more manufacturers with models for lower range, at least were 15yrs ago. Frydenbø Sabb Motor AS and another one I can't remember to name now..