Uncontrolled ascent today from 40ft - advice sought

[rongoodman]

Good thread everyone. I have had this issue in the past with AL tanks and had the exact same issue this weekend with a steel tank and was concerned. I switched from AL tank to steel to compensate for positivity at the end of my dive. I used to dive with 26 lbs with AL and now diving with 16 lbs and steel. I am using a Halcyon backplate and 7mm suit/hood and boots. I tried going horizontal to slow myself down but had a really hard time kicking back down. I am considering adding a 6 lb insert to my back plate to compensate.

What tank are you using? Off the top of my head, I can't think of any commonly used steel tank that's 10 lb heavier than an Al80 in the water. Also, while you're kicking down, all the air remaining in your wing will be right under the rear dump, where you can get rid of it.

 

[vcblklion]

What tank are you using? Off the top of my head, I can't think of any commonly used steel tank that's 10 lb heavier than an Al80 in the water. Also, while you're kicking down, all the air remaining in your wing will be right under the rear dump, where you can get rid of it.

I'm using a PST HP 100 and while I was ascending, I tried dumping air with my rear dump, my inflator and tried changing positions to release trapped air...still went up without stopping.

 

[rongoodman]

I'm using a PST HP 100 and while I was ascending, I tried dumping air with my rear dump, my inflator and tried changing positions to release trapped air...still went up without stopping.

A quick Google search found this chart, which shows your tank 1.3 lb neg empty, as opposed to about 4 lb positive for an empty Al 80. It looks like you dropped 5 lb too much weight when you switched tanks.

 

[Barry_Calgary]

Thanks for the post great advice by all, I also had a similar issue during my first OW dive and was a little embarrased to admit it. We were at 30ft and started our ascent at some point I felt the water dramatically warm up and realized I was only 10 -15 feet away from the surface., at this point I exhaled and tried to get into a horizontal position and dump whatever was in my BCD. Didn't help much as I surfaced 10 seconds later. I was quite concerned because I had been holding my breath for 15 feet or so but didn't feel any after effects.
Barry

 

[murdrcycle]

Not to undershine all of the technical and educated points here (no pun intended), but I thought I may go low-tech with this answer as I had a similar problem. No matter what, I couldn't get my weight right. Some dives I was overweight, some underweight. I don't dive very often so I thought is was fluctuations in my body fat. After much head scratching I realized that my wetsuit had an awesome ability to retain huge deposits of air even after I flooded it. Funny, but as soon as I figured that out and made sure my suit was completely flooded, not only did the fluctuation go away but I dropped almost 12lbs. of weight.

 

[scubacheeze]

I know how you feel about popping up from 40ft...the 2nd dive I did after I got certified (13 years old) I was spearfishing off of St. Pete with my dad and stupid me ran out of air. I tried to get his attention to get the octopus or just a breath from his, but he had just shot a fish and was too caught up in dealing with that to notice, so I just started blowing bubbles and kicking up! Scared me out of my mind...I was so mad at him and was sure I was going to be in the hospital but I ended up being ok.
Thanks DAD!
Sorry to derail, I just know how you feel and it is no fun

 

[Token]

Hmmmm....neoprene rebound... Interestingly, I have done some diving in a 7mm semi-dry and had a heck of a time trying to stay down for a safety stop, despite being a little heavy at depth. Dunno if this is the answer, but it's a possibility I'd consider.

 

[fjpatrum]

I would just ask one question, which may have been asked before. Why would you swing 6 pounds like that? An AL80 +gas is only about 4 pounds difference from an empty AL80, plus 6 pounds is a huge drop. I would try to dial in ideal weight by shifting <=2 pounds at a time. With small increments like that it's a lot easier to get close without massive swings that can hinder your control in situations like you had.

 

[IrishPaul]

I would just ask one question, which may have been asked before. Why would you swing 6 pounds like that? An AL80 +gas is only about 4 pounds difference from an empty AL80, plus 6 pounds is a huge drop. I would try to dial in ideal weight by shifting <=2 pounds at a time. With small increments like that it's a lot easier to get close without massive swings that can hinder your control in situations like you had.

Because I didn't know any better at the time. I assumed that 6lbs in the whole scheme of things was very little. Subsequent weight changes were much smaller.