Sudden ascent with SeaQuest Libra BC ???

[bwerb]

My quick read based on the new info is that at 30 feet, the neoprene expansion kicks into play and is what's making the 30foot to surface step start accelerating. I'd suggest she use her depth gauge carefully and as she approaches this "window" when the suit starts expanding...she starts dumping gas early. I think she can do it with the suit she has. The learning curve is taking the suit expansion into account and noticing where it becomes a factor.

 

[BILLB]

I dive the Balance and the wife uses the Libra. The horseshow shape of the back inflate bladder can trap air. There is a rear dump value but I doubt you can find it with heavy gloves on in cold water.

Next, The BC must fit so that the upper exhaust value is at the highest point when dumping air. If you tilt your body so the lower left side of the bladder is slightly higher than the lower right side, air will exhaust freely without trapping. Remember, to start dumping air first before starting an ascent. Infact you should be slightly negative when ascending. At this point you should be swimming (finning) to ascend. Especially when doing a free ascent.

When you are diving with your wife, notice the expansion of her back inflate bladder at depth. If it appears to be always full, she is overweighted. Most people think that the weight is is help then sink on the initial descent. When wearing heavy wetsuits, this can lead to overweighting yourself. Try dropping four to six pounds. If she cannot descend, then do a surface dive (head first) and this should get you down to about ten feet. At this point the wetsuit should be completely flooded and slightly compressed, thus making a feet first descent easier with less weight.

I dive with 20 pounds using the balance with a dry suit. I am about 5' 8" and 190 pounds. I do use a steel tank, but if I were using an AL80, I would add only 4-6 more pounds.

 

[kelpmermaid]

in our waters, both with a wetsuit and a drysuit, and haven't had any issues with it. I used to use a two piece 7 mil suit, but have switched to a one piece and hooded vest for wet dives. I also use a steel tankwhich might be another thought for her. There isn't as much "swing" to its bouyancy characteristics as the air is used, and I carry less lead. What size is your wife, if you don't mind my asking?

 

[TurtleDivers]

Thanks again to all who've taken the time to read and comment on this. In addition to your inputs we've also had 2 great conversations, one with DAN and another with SeaQuest, both of whom were engaging, thorough and constructive.

At this point it's clear that the Libra BC is perfectly suitable and not a factor in this problem. Although fairly experienced diving 3mm wetsuits, the recent change to 13mm seems to be the culprit and obviously requires a much more demanding focus on buoyancy change with depth. The recommendations for buoyancy/weight 'fine tuning' and more aggressive preemptive air release are all spot on. Our path now seems clear.

This is our first encounter here at scubaboard.com and the support from everyone is encouraging and gratifying. We hope to return the favor.

Safe diving!

 

[pearcey]

do a weight check whenever you change your equipment and sign up for peak performance bouyancy, it is great fun and a major improvement to any divers skill level.