Electronically controlled throttles for diesels sometimes add delay in, too. I suspect that's intended to protect the gearing and shafts. It may be a useful thing even on an all electric setup. Sheering the prop off the shaft would not be helpful.
Here's the J/109 saildrive location. I'd guess the distance to the rudder from the saildrive is almost the same as it is on the J/100. The J/109 is one of the easiest boats to drive and maneuver around the docks, forward or reverse. There is plenty of flow from the prop over the engine in forward to kick the stern one way of the other if needed. There is very little prop walk in reverse. Several times while backing down a narrow fairway into my slip, I had other "dock watchers" tell me it must be nice to have a bow thruster...
An “at the prop” rating must be shaft hp at the prop. Prop losses not included. Easy to measure with a dynomometer.
Each of the possible new engines delivers at least twice as much power as the current outboard. So why does the compariosson matter?
I'm no expert, but I would have thought that free-spinning would be less drag than locked in any position. It's going to be about 2feet behind a foil, in fast-flowing water, not tucked into a fat cutout on a long keel.
I was wondering if letting it freewheel might cause harm -- stresses diodes, burns bearings, wears seals, makes a horrible racket, to force a folding prop to fold, whatever. If so, then locking it might be a useful thing. Drag may not be the only consideration.
