NO SNORKELS ARE ALLOWED!!!! I dive in a lot of overhead enviroments and a snorkel is a big NO-NO! Even when I am in open water conditions, no snorkle. If the surface conditions are choppy, you have a minimum of two regs, why not use them? You will not run out of air/gas before coming upon your boat. Unless, of course, you have busted every minimum gas requirment. In that case, you have BIGGER problems.