I don't think it has been clearly mentioned that not all high-current dives are drift dives. Those that are can be a lot of fun. But experiencing strong currents and having to swim across or against them (for example, to get back to the boat or exit) is something else. Navy SEALs abort a mission if they have to swim far against a knot-and-a-half current. One learns to "read" the flow and find places to hide, and catch your breath. Staying close to the bottom or a wall is helpful, in the boundary layer rather than out in the free flow. Cave divers entering Ginnie Springs have all kinds of tricks to counteract the high flow against them. It is not all drift diving.
