Weight issue

[Jasonmh]

The correct answer is (1). In a bit more detail, minimum weight is that which you need to be neutral just below the surface with an empty BC, near-empty tank, and breathing normally. Then you can do a safety hang in comfort and ascend to the surface under control.

I agree. Your weighting should be done based on what you need at the end of the dive, not at the beginning.

 

[skywalk]

thank you for all the answers. i'll make sure i'm adequately weighted at the end of the dive on an empty tank.

 

[donacheson]

DAN has a good article on buoyancy control and weighting:

http://www.diversalertnetwork.org/medical/articles/article.asp?articleid=28

Unfortunately, it's not a very good article.

For example, anyone who weights themselves (as suggested in the article) to be neutral with 1320 psi in their tank (about 2 1/2 pounds of air in an Al80) at 15 feet, presumably with an empty BC and wearing a neoprene foam wetsuit, sooner or later will be out of control approaching the surface unless there's always a down line or anchor line to grasp or one always kicks head down/fins up. Don't count on the former and I don't recommend the latter if there's any boat traffic on the surface.

 

[jeffrey-c]

You're right, I agree. I've read the DAN article several times and for some reason keep missing the 1320psi reference. 500psi would be a much better point to weight for neutral buoyancy at 15 feet. I do think the article does a decent job of explaining all the factors involved with buoyancy, and was hoping it would provide a more comprehensive answer for the OP rather than sorting through a few dozen replies.

 

[donacheson]

You're right, I agree. I've read the DAN article several times and for some reason keep missing the 1320psi reference. 500psi would be a much better point to weight for neutral buoyancy at 15 feet. I do think the article does a decent job of explaining all the factors involved with buoyancy, and was hoping it would provide a more comprehensive answer for the OP rather than sorting through a few dozen replies.

While 500 psi at 15 feet is certainly better than 1320 psi at 15 feet, I'll go a lot further than that: neutral with 100 psi at 0 feet. I've done more than one dive in which something in shallow (15 or 20 feet) water has fascinated me and drawn my tank down deep into the red zone on my gauge. But a slow, controlled ascent from such shallow depths is easy even without air IF one is neutral all the way to the surface.

I have an issue with "Alert Diver". I believe that it had and still has an opportunity to be an authoritative dive publication. Unfortunately, DAN and its editors seem prone to publish some carelessly written and edited articles. While that particular article had some sensible things to say, it destroyed its credibility (in my mind) by including erroneous, even dangerous, statements. The reason that the neutral with 1320 psi at 15 feet statement gives me pause (and it's not the only staement in that article to do so) is that with a full 6mm full wet suit, a diver weighted to be neutral at 15 feet with 1320 psi with an empty BC will eventually find himself at 15 feet with 300 pounds, already 2 pounds light, and in ascending would become an additional 5 or 6 pounds lighter because of wet suit expansion. 7 or 8 pounds light is a struggle to control.