I have heard a lot of complaining about Crab fishing of late; since I myself have began dropping lobster traps I did some research on the subject and this is what I have found.
I do not believe you have to grab the trap right away when it "bobs", has anyone watched one sink after it "bobs"?
I saw one video where a player drops ten traps, moves the boat left twice, drops ten more, moves the boat left twice and drops ten more; then goes back and picks up all the first traps, checks them, drops them back in and moves left twice to continue on. When a trap sinks, he drops a new one in its place. I tried this a bit last night and yes, I did have a few sink, but I don't think it was any more than would normally if I was waiting on each "bob".
Seems like a much more efficient way to crab fish, and I was able to obtain crab much quicker using this method.