What I've done is to wrap the halyard around the boom at the exact same point I've attached the come-along. I've been able to position the engine in the cabin in such a spot I've lifted it straight up out of the cabin, and then swung the boom over. Yes, you might need to set the engine back down topsides and do some shuffling depending on how everything is lining up to then swing it over the side of the boat to lower it to ground/pier. A couple friends can also probably help guide/hold it off at an angle if you're close to being able to drop it straight down but need just a little adjustment. I have not done this on an E38 specifically, so I can't tell you to attach everything at x precise spot, but with a little eyeball work, you ought to be able to get things to line up and a couple friends and some beer incentive when all done seems to have done the trick for me in the past. I've also used the boom to move the engine below for the scoot out from under the cockpit to under the companion way. Even at an angle with the come-along, I was able to get enough lifting action to ease the engines off their mounts, move them into the cabin, make some adjustments perhaps, and the lift and swing and down. Take is slow, triple look everything over, and I bet you can make this work.