I knew that this post was going to fuel
up once more the old chore once again
and stirr up the water
Look, the VOLVO
manual (clearly written for a shaft drive) outlines also the implicit danger
, i.e., the propeller will spin and so will the inner gears in the bowels of the saildrive and of the engine, but with the engine off there will be no proper cisrculation of (warm) oil
and so they recommend to crank in the engine every so many hours.
Their concern is not obviously the wear that you are imposing on the gears but that something locks or seize unexpectedly and so they shall either replace it under warranty or at least explain why it may have failed.
Of course a progressive and gradual (but senseless) wear like the one caused by a free spinning propeller can only play in their hands since they'll sell more spares as a consequence of it.
i can't imagine a ocean passage
with a whirling and vibrating prop under the belly of the boat for a leg of 5,000. Nm. Of course if you are just motoring out of the marina, sailing for a few hours and motoring back in, then is none of your concern. You can easly do whatever you want and be happy with the outcomes anyway.