Posted by Chris on April 12, 2005 at 11:07:42:
In Reply to: Gotta agree...too much drag posted by Walt on April 12, 2005 at 09:35:40:
I agree about the bigger tank. I use an HP120 for boat diving ange for most dives I return with more than 1000 psi, however it is nice to have the extra air when I need it.
For beach diving I now use an HP80.
I gave away all of my AL 80's years ago. I hate the bouyancy, and the extra weight needed to compensate for it. A Al 80 is about +5 lb. at 500 psi, a HP120 is nuetral at 500 psi, and a HP80 is about -2 lb. at 500 psi.
If the difference in the HP 80 vs. HP 120 bouyancy does not make sense, think of it like this. Both tanks have the same wall thickness. Thus when empty the dead space volume vs. wall volume is greater for the bigger tank, thus the increased bouyancy.
The other advantge of HP tanks is that they use DIN valves which are far more reliable than Yoke valves. I have never seen a DIN valve pop an o-ring or come loose durring a dive, I can not say the same for yoke valves.