A while back someone at Amel told me to always leave it in forward and to never even put the transmission in neutral when sailing. The explanation was that the Autoprop will spin in reverse (or try to) when the boat is moving forward. The idea is to stop the engine with it still in gear and then push it all the way forward. To start the engine, pull back on the throttle as far as possible while leaving it in gear. Then start the engine. Putting the transmission in neutral allows the prop to spin—fast in reverse. Then when you move it into gear, the small clutches in the transmission get a ferocious bang. They don’t last very long with much of this treatment. Leaving it in forward makes sure that the transmission never is subjected to a shock.
This has worked for me for over 45,000 miles.
Miles Ladybug sm216 Martinique