This is the big boat lift at Liberty Harbor Marina. I'm not sure how this one works, but when I was a young adult I had a friend who worked in a marina and the ones they had used these huge straps that went beneath the hull of the boat and then lifted it like it was in a sling. My guess is this one is like those only the straps do not look like they are attached.
Coming back to AM3 after a long hiatus. I hope to be more active in the coming months.