I've used grapples with success on water. I've also cursed and cussed with a coon and a grapple wrapped up high in a tree.
Better ways to drag a coon in water like you describe than "real" drags.
Some of this stuff is a pain to haul, I understand- but if available- use it.
Old tires are excellent to drag coons with. I have 7-8 of them on y line that I found in the creek and use every year. At end of season, I just haul them out of the water and wire them to a tree. A tire half full of water and the coon is going nowhere.
Concrete blocks also of course.
What I use most of the time on daily checks in shallow water are long branch drags. Usually where a lot of coon, there are trees. Look for a branch at least 10 feet long- the more multiple branches the better. Minimum width about like your arm. Coon haul these up and down the creek- easy to track and usually get hung up in a drift pile. Wire trap to middle of branch- also cuts down on chewing in a major way on these branch drags.