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Slims · 06-20-2009, 10:32 AM

I 'third' the buoyancy advice. One of the easiest ways to practice this in a pool (when you first start out) is to lay flat on the bottom of the pool and slowly breath small amounts of air into your BC until you rise up onto your fin tips when you inhale and sink when you exhale.

Just remember that your buoyancy decreases as you descend, requiring you to add a little air to your BC and the reverse is true in ascent....divers who do not bleed extra air when they ascend sometimes end up rocketing to the surface due to stupidity.

Unlike Tully who I guess carries extra weights to help fix others, I try to use as little lead as possible because the more lead you use the more your buoyancy will change as you alter your depth (because you will have to use more air in your BC which is compressible). Just remember that you need to add an extra couple pounds to compensate for your tanks becoming slightly buoyant during the course of your dive.

A single AL-80 tank (usually the standard) is about 2 lbs negatively buoyant when full and 4 lbs positive when empty. Of course, you won't typically stay submerged until you flat out run out of air, so you don't need to pile on a full 4lbs for each tank, but 2lbs lead per tank (i.e. if you dive twin tanks then use 4 lbs lead) is a good rule of thumb in addition to any lead you need to stay submerged (natural buoyancy, wetsuit, etc.).

When I dive twin 80's I usually only wear 6 lbs of lead, and it is more than enough for me to stay down without fighting provided I don't drop below about 800psi. If I know I will be pushing the limits of the tanks I will add a little more.

Not over-weighting yourself makes it much easier to control your buoyancy...you will notice that some people pile on the lead and are constantly either sinking or floating up...forcing them to continually waste air by inflating/expelling air from their BC.

06-20-2009, 10:32 AM	#10 (permalink)
Slims Eccentric insomniac Location: North Carolina	I 'third' the buoyancy advice. One of the easiest ways to practice this in a pool (when you first start out) is to lay flat on the bottom of the pool and slowly breath small amounts of air into your BC until you rise up onto your fin tips when you inhale and sink when you exhale. Just remember that your buoyancy decreases as you descend, requiring you to add a little air to your BC and the reverse is true in ascent....divers who do not bleed extra air when they ascend sometimes end up rocketing to the surface due to stupidity. Unlike Tully who I guess carries extra weights to help fix others, I try to use as little lead as possible because the more lead you use the more your buoyancy will change as you alter your depth (because you will have to use more air in your BC which is compressible). Just remember that you need to add an extra couple pounds to compensate for your tanks becoming slightly buoyant during the course of your dive. A single AL-80 tank (usually the standard) is about 2 lbs negatively buoyant when full and 4 lbs positive when empty. Of course, you won't typically stay submerged until you flat out run out of air, so you don't need to pile on a full 4lbs for each tank, but 2lbs lead per tank (i.e. if you dive twin tanks then use 4 lbs lead) is a good rule of thumb in addition to any lead you need to stay submerged (natural buoyancy, wetsuit, etc.). When I dive twin 80's I usually only wear 6 lbs of lead, and it is more than enough for me to stay down without fighting provided I don't drop below about 800psi. If I know I will be pushing the limits of the tanks I will add a little more. Not over-weighting yourself makes it much easier to control your buoyancy...you will notice that some people pile on the lead and are constantly either sinking or floating up...forcing them to continually waste air by inflating/expelling air from their BC. __________________ "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery." - Winston Churchill "All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find that it was vanity: but the dreamers of the day are dangerous men, for they may act out their dream with open eyes, to make it possible." Seven Pillars of Wisdom, T.E. Lawrence Last edited by Slims; 06-20-2009 at 10:38 AM..