This was the first season I fished with a crab fly and it proved to be VERY effective. I only caught one while sight fishing and it was lip hooked. The other fish were all caught using a controlled swing in the current and above the bottom. The technique seemed similar to skating a fly for stealhead except its underwater. Many of those fish were lip hooked and all of them were hooked clear of vitals (kind of a "deep" lip hook). It seems to me, inexperienced as I am, that the danger of deep hooking would arise most prominently during the slack line bottom presentation and that an indicator could prove quite valuable. I think next season will see me equiped with a couple indicators.