I’ve done them in the water before. The boat is new to me, and was on the hard for 5 years it wasn’t bad when I splashed, but got much worse during the trip. I tried to tighten, but the assembly is stuck. I think it will take some beating to free up. I’d rather have the slings under her or hauled out, if shit goes bad when trying to free it upyou can add or change packing with the boat in the water. have everything ready and go for it, probably wont get 5 gallons of water in the boat