The type of set will have to depend on the situation.
As far as drowners, yes you can use them in really rocky areas much of the time.
First, determine if you can make a set
Make the set.
Take your drowner, set it out on the ground where you want it to run.
Determine if you need a drowning weight at the deep end or not.
If the area is really rocky, take the drowner, bury the end of it, with a stake pushed about 1/2 way through the loop or twist, and pile rock on top of it untill the critter can't move it.
the drowner should come out of the rock in close proximity to the set so you can hook your trap to it and still reache the set.
You can pile rocks on the deep end the same way, or you can use sand bags.
I have had to do this before, I hate doing it, but if the area is too hot to pass up.....
