I haven't read all the posts but I have a couple of comments. An up signal is a non-negotiable command. You must make an agreement with your dive buddies that when the thumb goes up the dive is over. No questions asked!
Another item is I would continue to breath off a free flowing reg for as long as there is air in the tank. It is going to blow off the same amount of gas anyway, you might as well use some of it. What benefit does turning off the valve provide other than slowing the acsent?
Another item is I would continue to breath off a free flowing reg for as long as there is air in the tank. It is going to blow off the same amount of gas anyway, you might as well use some of it. What benefit does turning off the valve provide other than slowing the acsent?