Mailing List Archive Mailing List Archive
Bill Lais <billlais@mp*.ne*> writes: > I have a good friend who only dives AL80s. He doesn't add any weight at all > when he's diving fresh, but adds about 3 lbs when diving salt water. 16 > lbs?? Formula for a freshwater diver going to the salt: fresh water is 62.4 pounds per cubic foot, and salt water is 64.0 lbs/cf. Therefore, figure out your all-up weight (you, your tanks, gear, fins, correct weight for fresh, everything you've got walking into the water). Divide by 62.4 and that's the number of cubic feet of water you displace. Multiply by 64.0 and that's what you need to weigh to be neutral when you jump into salt water. The difference is the lead you need to add. Archimedes figured this all out long ago in his bathtub. 3 lbs and 16 lbs would both be out of line for a reasonably-sized diver; if your friend is adding exactly the right amount of lead, then he weighs around 80 lbs himself for a total of around 120 lbs with that AL80, and that's assuming a really light regulator. (If we ever get Jim to dive in fresh water, he'd need to swap those numbers to figure out how much lead to take off.) I've done this exercise a couple of times before for different configurations (diveskin off Providenciales, drysuit off North Carolina) and come out right the first dive both times without needing to adjust. -- Anthony DeBoer <adb@on*.ca*>
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]