Since we’re not sailing, we’re thinking about sailing. Specifically, we’re thinking about what to do with the prop while we’re sailing.

We have a huge fixed prop. Huge. This is great for motoring.

But when we sail, the prop spins as the water moves past it. It moves a lot, and it’s hard to stop. I’m guessing (wildly) that it could generate 25 hp at 7 kts. Really hard to stop.

Conventional wisdom says that it’s better to lock the shaft while sailing – that there’s less drag on a fixed prop. Conventional wisdom is wrong, and once again “Maine Sail” did the work to prove the issue. This guy is amazing: http://www.catamaransite.com/propeller_drag_test.html.

The downside to letting the shaft spin is that it spins the transmission, without making the transmission fluid run through cooler, and the transmission gets hot. Really, really hot. The other downside is that the prop and shaft are noisy, almost as noisy as the motor running.

So, in Mexico, we’ll continue to motor sail, running the motor whenever we move. If we choose to sail offshore, on multi-week passages, we’ll buy a folding or feathering prop, probably a Gori, that changes from a propeller to a streamlined blob when the shaft isn’t being turned by the engine. These props are crazy expensive in the size we need. Several years of diesel expensive.

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