No BC diving is something I do quite often, including around 15 dives in the last 5 days, 3 today. The first suggestion I have if you want to learn how it's done is to totally ignore anyone who does not actually dive that way on a regular basis. Not to be crude but they have no idea of what they are talking about. Comments like "aluminum tanks get light and you can't control the swing" pretty much tells me they have no clue. 80 cf of gas is 80 cf of gas and has a 4 to 5 lb swing depending on how low you drain a tank. The buoyancy swing of 1 cf of gas is exactly the same regardless of the tank material. Granted the tank material and size do have a major impact on your total weighting but the tank material has no impact on the overall buoyancy swing of a tank. As a matter of fact, I dive al tanks almost exclusively in warm fresh water because of their buoyancy characteristics, steels over weight me. I could use steels in warm salt water but since most places rent AL-80s I have to add weights to offset the AL tank....I use 4 lbs of lead in salt water. I rarely dive sans BC in cold water so I will yield to ZYK's expertise for cold water but in water that is 70+ deg I dive sans BC almost exclusively unless I am working with a class. The idea that you cannot hover nor do safety stops is pure BS. I do it all the time, including safety stops and looking at fish today. I also carry a camera a lot of the time which requires near perfect buoyancy control, I do it with no BC and usually a double hose reg with no problems. Its all about proper weighting, trim and breathing control. Breath control is a lot more than simply inhaling and/or exhaling deeply. The depth of your breath is important but cadence and timing play as much of a role as breathing depth. Don't get me wrong, I do wear a BC when I see the need, like diving way off shore when I may need the BC to act as surface floatation if I get away from the dive boat or when diving in very cold water with thick wetsuits and I don't want to mess with rocks or dropping weights but the idea that its difficult or you can not control your bouyancy is completley untrue.....or I have been doing the impossible for the last 5 days..
