I don't use any kind of drowning rig for mink or muskrat. I put a few feet of cable, chain or wire on s trap. When I get there the next morning they hav re drowned. I guess they start swimming and the weight of the trap keeps them down until they drown.
I've done that too. But I always catch alot of coon and that doesn't drown them for me. Why I'm doing the rods