Question about tank specs... specifically steel 72's

[Mo2vation]

My understanding is there are several designs of steel 72's (as opposed to a much narrower field of, say HP100's) - so here's my thing.

I dive the E8-130 waterheater. Got myself dialed in weighting and positioning, etc. for that cylinder. I dive 8 pounds, with a DS and my Steel BP and little can light.

But I've been out of the water for a bit, and lost weight. So yesterday I get in with a steel 72 - and 10 pounds of weight. I was arrestingly under-weighted. I grabbed a couple of rocks, and finished the dive - but I was very uncomfortable.

Next dive I bumped up to 16 pounds, and I was about spot on. Much better. Did the 500 PSI / 10' test - no worries.

I guess I'm fishing here, and now that I've got it nailed its a waste of bandwidth, but I mean WOW. I had no idea I'd need so much more weight for such a smaller tank...especially because the waterheater is like 10+ neg.

Could it be gas trapping in my suit, now that its way big on me? I purged as best I could, and I usually just add a couple of puffs, anyway. Could that be why I needed to essentially double my weight and add another full 8 pounds? Or are 72's just that much lighter? The tank monkey at the park said "neg 4" for the 72... anyway. I was shocked I needed to get to 16 to get comfy.

Any thoughts on this? Is it a combo of my weight loss, air trapping and the 72 bring that light? Am I mental? Always a possibility.

I feel good that I got the 72 dialed in. Schlepping the waterheater to the island for day trips was getting old. If I can rent on-site, cool. I only get about 30 - 40 minutes out of it, but I've dove the park a zillion times. So I'm pretty excited about losing the tank-lug. Just wondering about adding so much weight.

I'm not too familiar with body dynamics and how weight loss (for me, like 15 - 18# or so) impacts scuba weighting. Do you need more weight, less weight...? Just curious what caused this - the tank, the bod, or both.


Thanks

K

 

[whalerkyle]

Wassap Ken,
I have a SS backplate, 20 lbs lead, 7mm suit. I dive AL 80's and Steel 72's without changing the weight.
When I go to an HP100, I can loose 10 lbs of metal.

Glad your back in the water. So all I need to do to loose some gut is gimp my self eh?

Kyle

 

[Mo2vation]

Glad your back in the water. So all I need to do to loose some gut is gimp my self eh?

Kyle

Not worth it. Trust me.




K

 

[Brian Gilpin]

My understanding is there are several designs of steel 72's (as opposed to a much narrower field of, say HP100's) - so here's my thing.

I dive the E8-130 waterheater. Got myself dialed in weighting and positioning, etc. for that cylinder. I dive 8 pounds, with a DS and my Steel BP and little can light.

But I've been out of the water for a bit, and lost weight. So yesterday I get in with a steel 72 - and 10 pounds of weight. I was arrestingly under-weighted. I grabbed a couple of rocks, and finished the dive - but I was very uncomfortable.

Next dive I bumped up to 16 pounds, and I was about spot on. Much better. Did the 500 PSI / 10' test - no worries.

I guess I'm fishing here, and now that I've got it nailed its a waste of bandwidth, but I mean WOW. I had no idea I'd need so much more weight for such a smaller tank...especially because the waterheater is like 10+ neg.

Could it be gas trapping in my suit, now that its way big on me? I purged as best I could, and I usually just add a couple of puffs, anyway. Could that be why I needed to essentially double my weight and add another full 8 pounds? Or are 72's just that much lighter? The tank monkey at the park said "neg 4" for the 72... anyway. I was shocked I needed to get to 16 to get comfy.

Any thoughts on this? Is it a combo of my weight loss, air trapping and the 72 bring that light? Am I mental? Always a possibility.

Thanks

K

Could it be that being out of the water is part of the problem? Dont panic just yet. I took two months + off this last winter and needed more weight than expected also upon my return.Of course the tank was obviously the biggest factor.Are you using a weighted STA? Might be a good idea with smaller tanks. Hold off on ordering the pizza as I would think your weight loss would mean you need less weight not more.Fat floats.

 

[wedivebc]

My understanding is there are several designs of steel 72's (as opposed to a much narrower field of, say HP100's) - so here's my thing.

I dive the E8-130 waterheater. Got myself dialed in weighting and positioning, etc. for that cylinder. I dive 8 pounds, with a DS and my Steel BP and little can light.

But I've been out of the water for a bit, and lost weight. So yesterday I get in with a steel 72 - and 10 pounds of weight. I was arrestingly under-weighted. I grabbed a couple of rocks, and finished the dive - but I was very uncomfortable.

Next dive I bumped up to 16 pounds, and I was about spot on. Much better. Did the 500 PSI / 10' test - no worries.

I guess I'm fishing here, and now that I've got it nailed its a waste of bandwidth, but I mean WOW. I had no idea I'd need so much more weight for such a smaller tank...especially because the waterheater is like 10+ neg.

Could it be gas trapping in my suit, now that its way big on me? I purged as best I could, and I usually just add a couple of puffs, anyway. Could that be why I needed to essentially double my weight and add another full 8 pounds? Or are 72's just that much lighter? The tank monkey at the park said "neg 4" for the 72... anyway. I was shocked I needed to get to 16 to get comfy.

Any thoughts on this? Is it a combo of my weight loss, air trapping and the 72 bring that light? Am I mental? Always a possibility.

I feel good that I got the 72 dialed in. Schlepping the waterheater to the island for day trips was getting old. If I can rent on-site, cool. I only get about 30 - 40 minutes out of it, but I've dove the park a zillion times. So I'm pretty excited about losing the tank-lug. Just wondering about adding so much weight.

I'm not too familiar with body dynamics and how weight loss (for me, like 15 - 18# or so) impacts scuba weighting. Do you need more weight, less weight...? Just curious what caused this - the tank, the bod, or both.


Thanks

K

....OOps

 

[LobstaMan]

It's probably more the time off than anything else. I was out of diving for many years and just got back into it in 2002. Did a few more dives in '03 and even more in '04. With the exact same set-up all season(72 steel incidentally), I have been able to drop 7 or 8 lbs off my belt since May. I'm 6' 205 lbs use a 7mm 2 peice, BCD, a steel 72 w/ 6 lbs in the BCD pockets and 16 on the belt. It seems, the more I dive, the more comfortable I get and the more weight I'm able to drop. Good luck diving.

LobstaMan