I am not sure that 2hp is going to move a M39. Even when becalmed there always seems to be a swell too. I spent a couple of days becalmed in Biscay some years ago. The skipper
even said "take the spinnaker
down because it isn't doing any good, oh and you lot can go for a swim, here is some sea soap".
We eventually found some wind
and made it to La Coruna. However, a Contessa 32 wasn't so lucky. They came in to the marina a day after us under sail, dropped the sails
at the last moment and did a text book mooring
down a dead end of the pontoons, all very impressive. Later I asked them why under sail? They explained that they ran out of diesel
30 miles offshore
and spent 3 days drifting back and forth with no wind
I have been following "Adventures of an old Sea Dog" on YT and his recent Pacific crossing, which didn't go well. The weather
seemed to be constantly against him and his sails
weren't in a good condition which meant an average speed of 2.7 knots. Other problems included the hull
fouling up with weed.
To avoid this it might be worth adding a second hand cruising chute. Doesn't have to be anything special or even a perfect fit, but it will provide some drive in very light conditions. Do you have a boarding ladder? you might think about adding a bracket so the outboard engine
can be used to drive the Moody. Here is a solution for a smaller Moody which came off the owners association. I keep meaning to copy his design.