Uncontrolled Ascent
- Thread starter Lehmann108
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Glad the guy is alright.
However, let me run through this step by step. I understand he needed more weight to get down, but he did get down to the 97 ft. At this depth he would have needed no weight at all to keep him down; not the extra 5, not even any (although this would be problematic once at 40ft and up, but for the moment, fallow with me). The guy looses his 5 extra lbs at 97 ft. Should not have be a problem other than noticing a sudden tendency to ascend. However at that depth he should already have had to add so much air to his bc that he would have had plenty to dump and more than compensate for the 5 lbs he lost. Even if he was parallel with the ocean bottom and had trapped air in his bc by not pointing to the surface, at that depth I'm struggling to understand how the loss of 5 lbs at 97 ft caused a run-away ascent. Obviously, he did ascend too rapidly and I'm glad he is ok. I just think there must be more to what happened above and beyond the loss of 5 lbs. BTW was it the same 5 lbs that that instructor added for him? If so did the instructor fail to Zip it in?
However, let me run through this step by step. I understand he needed more weight to get down, but he did get down to the 97 ft. At this depth he would have needed no weight at all to keep him down; not the extra 5, not even any (although this would be problematic once at 40ft and up, but for the moment, fallow with me). The guy looses his 5 extra lbs at 97 ft. Should not have be a problem other than noticing a sudden tendency to ascend. However at that depth he should already have had to add so much air to his bc that he would have had plenty to dump and more than compensate for the 5 lbs he lost. Even if he was parallel with the ocean bottom and had trapped air in his bc by not pointing to the surface, at that depth I'm struggling to understand how the loss of 5 lbs at 97 ft caused a run-away ascent. Obviously, he did ascend too rapidly and I'm glad he is ok. I just think there must be more to what happened above and beyond the loss of 5 lbs. BTW was it the same 5 lbs that that instructor added for him? If so did the instructor fail to Zip it in?
Hemlon
Contributor
I'm glad that you are ok!
msdiver04
Registered
There are a lot of problems with this situation, but it brings to mind something I have been thinking about for a while. My daughter got her open water certification, and when she was done and back home, she told me her instructor was always grabbing her and scaring her, so she didn't feel at all confident. The following summer, we went to Honduras and dove for 6 weeks. By the end, she was ready to do her advanced open water class, and she did fine. She and I talked about everything, and I came to the conclusion that for many people, it's best to get some experience before doing the advanced open water class. As one person wrote here, at this point, you are more comfortable and can attend to the demands of deep diving, etc. I believe PADI should require open water divers to do at least 10 more dives after open water before doing the advanced course.
In all of my instructor/DM experience, I have noticed a few things that just seem to happen on deep dives.
First...Descents...I see more people claim to have a hard time initially descending and think they need more weight when in-fact most are just a little nervous and take a big inhale and hold their breath right when they start to let air out of the BC, and then continue to breath shallow and rapid, keeping there lungs inflated. When I encounter this, I remind them to exhale, stay calm and that usually fixes the decent issue with no need for additional weights. If weight is needed then I go 2 lbs at a time (I carry 4 lbs extra)
Second, I also see many divers who seem to think the LPI will work to drain air when horizontal, but when it doesn't, they don't realize the problem and just continue to try, most try to push the drain button "harder" thinking that will help, all the while they are slowly rising and due to the air expansion in the BC, their ascent rate increases. From 97 ft this "can" turn into a big problem.
Third, If you combine these two conditions and have someone who was over weighted (if they added weight) and needs more air in the BC to achieve neutral buoyancy at depth, then when they finally relax and stop shallow breathing, they have to add more air to the BC, thus increasing the risk of becoming positively buoyant due to a slight depth change.
If this was the case with this diver and they lost the extra 5 lbs then they would become instantly "positive" and the result would be just as it was explained.
I have seen MANY divers look at me helplessly as they rise, all the while trying to dump air using the LPI while laying flat. The way I prevent these issues is:
1. Always checking weight of each diver first regardless of cert rating or experience.
2. Look for the signs of nervousness (Shaking hands, darting eyes, excessive sweat, etc). If spotted then that diver never leaves my side from surface to depth, until I feel they are OK, even if that means my work is doubled to conduct and AOW.
Glad this guy is OK but I believe the incident could have been easily prevented if the above steps were followed.
JMHO
First...Descents...I see more people claim to have a hard time initially descending and think they need more weight when in-fact most are just a little nervous and take a big inhale and hold their breath right when they start to let air out of the BC, and then continue to breath shallow and rapid, keeping there lungs inflated. When I encounter this, I remind them to exhale, stay calm and that usually fixes the decent issue with no need for additional weights. If weight is needed then I go 2 lbs at a time (I carry 4 lbs extra)
Second, I also see many divers who seem to think the LPI will work to drain air when horizontal, but when it doesn't, they don't realize the problem and just continue to try, most try to push the drain button "harder" thinking that will help, all the while they are slowly rising and due to the air expansion in the BC, their ascent rate increases. From 97 ft this "can" turn into a big problem.
Third, If you combine these two conditions and have someone who was over weighted (if they added weight) and needs more air in the BC to achieve neutral buoyancy at depth, then when they finally relax and stop shallow breathing, they have to add more air to the BC, thus increasing the risk of becoming positively buoyant due to a slight depth change.
If this was the case with this diver and they lost the extra 5 lbs then they would become instantly "positive" and the result would be just as it was explained.
I have seen MANY divers look at me helplessly as they rise, all the while trying to dump air using the LPI while laying flat. The way I prevent these issues is:
1. Always checking weight of each diver first regardless of cert rating or experience.
2. Look for the signs of nervousness (Shaking hands, darting eyes, excessive sweat, etc). If spotted then that diver never leaves my side from surface to depth, until I feel they are OK, even if that means my work is doubled to conduct and AOW.
Glad this guy is OK but I believe the incident could have been easily prevented if the above steps were followed.
JMHO
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