Is overweighting of OW students a violation of standards?

[boulderjohn]

What the hell is a fin pivot? And why would I want to do one?

Edit to add:

Well blow me down, what do you know, a fin pivot is where divers lay on the bottom (reef) and then smash it going up and down as if doing push ups. No wonder folks cannot dive and are destroying the bottom. Well, I cannot agree with everything I found on this website courtesy of Google but I kind of like the fact they just say no to the odd and rather weird concept of fin pivots:

Buoyancy Control | NASE Worldwide Diver Training Blog

James

You are correct on all counts. PADI stopped requiring the fin pivot for the OW dives about 10 years ago, and it stopped requiring it for pool sessions shortly after that. The phrase "fin pivot" does not appear in the instructor manual now, and it has not been in there in years. Any instructor using it in OW now is a decade behind the times. Even in the pool, as the course progresses, one of the standards is that students are to treat the bottom of the pool as if it is a delicate marine environment and avoid touching it.

 

[Bob DBF]

I'm slightly confused. If you are neutrally buoyant at 15 feet with no air in the BC wouldn't you get slightly positively buoyant as you ascend to the surface? I do my weight checks this way but go for neutral while doing shallow exhales and deep inhales. Am I over thinking this?

Yes you would. Breathe normally. No.
I normally weight a pound or two over that, in case I need more air at 15' or want to hold a stop at less than 15'.

However, if you were you were weighted this way, you would be negative on the surface at the beginning of the dive by the weight of your air. We are talking 6# for my old Faber 120, less with a smaller tank. So if you are neutral or positive at the beginning of the dive with the BC empty you better grab some old school lead (rocks) on the dive or you may not be making a safety stop without an anchor line.

There are some factors that may make you more positive on the first dive, the wetsuit has not been crushed yet, the BC material is still dry and holding more air and the padding has not been crushed yet, and so on. If you hold the safety stop, make sure you have some air in the BC when you get in for the second dive, you might need it.



Bob
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"This is scuba board, where problems are imagined or overstated......and chests get thumped about what some would do about those "problems" "- PullMyFinger

 

[boulderjohn]

The degree to which one should add weight to compensate for the loss of air during a dive is a subject for debate. It has, in fact, been debated in past ScubaBoard discussions. One side of the argument says that if you float at eye level holding a normal breath at the beginning of a dive, you need to add the amount of weight equal to the weight of the air you will use. The other side of the argument says that you probably have that much buoyancy in the form of trapped air in both the wet suit and the BCD, trapped air that will go away quickly during the dive. Personally, I prefer a couple extra pounds so that as I ascend and need to vent air, it is easy to get that bubble to an exhaust port. If I am very closely weighted, I have to do too much twisting and turning to get that tiny bubble where it needs to be.

The best teacher is experience, and as we dive, we will gain a lot of experience. I will dive at different times wearing a 3mm wet suit, a 5 mm wet suit, or a dry suit. I will breathe at different times from an AL 80, a Worthington steel LP 85, double Worthington steel LP 85s, double AL 80s, or double Worthington steel LP 108s. I may be carrying stage bottles and/or deco bottles. I dive in fresh water and salt water. Those are just the combinations I normally use--I could also borrow different gear. The potential combinations are dizzying. I try to keep notes on what works and what doesn't work in my dive log.

 

[Eric Sedletzky]

Not necessarily. I went into my AOW wearing 24 lbs of lead in cold fresh water with a full 7 mm farmer jane wetsuit, hood, gloves, and boots, a petite female, weighing a little over 100 lbs. I did my first weighting check ever during the AOW, and sank 10 feet with an empty bc and holding a normal breath. I went to remove weight at the shore beside us and the DMC said, "It's ok, it'll even out by the end". My buddy and I did the navigation with the DMC, and she didn't like my trim, so she kept asking her husband, a DM, for more weight to hang on me in various places - totalling 33 lbs, which felt awful. My ladies BC had a lift of 25 lbs. The instructor was in the general area, within 50 feet away, with other students.

I then went to do the peak performance buoyancy with the instructor through hula hoops, and it was a nearly impossible constant extreme challenge managing the air in the bc. I finally signalled to the instructor to watch me and I laid on the bottom and fully inflated my bc, obviously burping it many times, and still flat on the bottom. He just looked at me and shrugged his shoulders, apparently not understanding that I looked like a christmas tree with all the hanging weights. I had to kick to initiate an ascent. Afterwards I told him that I am extremely overweighted, and wanted to take all the extra weights off and he said "No, keep them on".

During the night dive, where we were supposed to stop and hover at 30 feet, I could not stop my descent with a fully inflated bc and the 33 lbs of lead and went freefalling to the bottom at nearly 60 feet, with the whole group coming with me. Nobody stopped before the bottom and everyone failed the night dive.

The second day the co-owner was there and saw me about to get into the water and couldn't believe her eyes. She asked me how much weight I was wearing. I told her 33 lbs and told her I sank 10 feet during the weighting check with 24 lbs. She told me to take all those weights off and go down to 20 lbs. I was so relieved. I asked if I could try 22 lbs since I had a hard time descending. She said ok, and took me for my multi-level dive. She said we would not go past 70 feet on the first dive and see where I'm at, although she knew that I was OK before the AOW. She taught me tricks to descend efficiently, hover motionless, use my lungs proactively, and kick efficiently - all in one dive. With the descent techniques she taught me, she asked me to try 20 lbs on the next dive, the deep dive, and I did, and for the first time, I knew what it felt like to be perfectly neutral. She had me hold various stops without a line horizontally and motionless, and I was amazed at how neutral I was.

That evening we all repeated the night dive with some actual instruction and all went well. The third day, I did my 2nd and 3rd deep dives for the deep specialty, all went well, and I passed the AOW and Deep specialty. Thanks to one dedicated and fabulous instructor. Yes, I told her that most of my skills were done with the DMC, not the instructor, and she was appalled.

So, the point of my long story is that some students may be so grossly overweighted that a fully inflated bc cannot lift them off the bottom. And some instructors don't recognize this or don't correct it.

This is exactly what I'm talking about. The instructor that overweighted you to the point that you were pinned on the bottom even with a fully inflated BC should have been written up or possibly dismissed. That's not only wrong it's flat out dangerous and in some cases life threatening.

---------- Post added August 2nd, 2015 at 10:26 AM ----------

I'm slightly confused. If you are neutrally buoyant at 15 feet with no air in the BC wouldn't you get slightly positively buoyant as you ascend to the surface? I do my weight checks this way but go for neutral while doing shallow exhales and deep inhales. Am I over thinking this?

Doing the 15' stop at the end of the dive with 300 to 500 psi in the tank and a completely empty BC is the way to find out exactly how much weight you need, no more no less. Beyond that, once somebody knows this number then they can add a few to make up for a drysuit or for whatever reason. Personally I like to shave my weighting down to the bare minimum because I don't want to have to pack any extra on land/the beach if I don't have to, and it makes the final stop so effortless when there is no air expanding and pressurizing in the bladder right at that pressure critical 15' zone. To be able to control a stop with breath control alone is a beautiful thing.
And your question about "won't you get floaty above 15'", Yes you will, but you won't rocket to the top. Rocketing only happenes when an air bubble gets out of control. Wetsuits expand slowly and the rise is much more gentle. Unrevokable positive bouyancy on the surface, meaning bouyancy that can't be taken away by equipment failure i.e., broken inflator elbow, complete failure and flood of a drysuit etc. If a diver is grossly overweighted then a sudden loss of a fabricated airspace (balloon) which supports surface floatation can present severe problems. The solution of course is to dump weight but I have examples of where that failed.
There are two things that will provide unrevokable buoyancy at the surface, wetsuits which the positive bouyancy can't fail, and body fat. In my case it just so happens that when I set myself up to the 15' rule it also means that I am positively buoyant on the surface at the beginning of the dive with no air in my wing. That's just how the math works out. That's with a 7mm wetsuit, with a 4mm I can do the same thing but I have a very small weightbelt.

 

[boulderjohn]

So, the point of my long story is that some students may be so grossly overweighted that a fully inflated bc cannot lift them off the bottom. And some instructors don't recognize this or don't correct it.

There is an assumption that all instructors fully understand weighting and neutral buoyancy. That is a fallacy. It is really not a part of DM or instructor training, which focuses on the ability to teach basic skills. That has traditionally meant, as mentioned before, doing skills well while firmly planted on the pool floor on the knees. There is no real assessment of weighting and trim in that training. Once certified, the new instructor is allowed to teach peak performance buoyancy and train future DMs.

This is exactly what I'm talking about. The instructor that overweighted you to the point that you were pinned on the bottom even with a fully inflated BC should have been written up or possibly dismissed. That's not only wrong it's flat out dangerous and in some cases life threatening.

Yes, it can be fatal. A couple years ago an instructor conducted a Discover Scuba class for boy scouts, and the divers were about as overweighted as Ayisha describes in her post. One of the students died after the instructor left him alone while going to the surface in shallow water to tend to someone who lost buoyancy control and surfaced. The actual reason for the death is not clear, but he did appear to have trouble staying off the bottom with a full BCD.

A key problem with overweighting is loss of buoyancy control, particularly in shallow water. Every unnecessary pound requires the volume equivalent of about 15 fluid ounces of air--about a pint--to balance the extra lead. Put enough extra lead on the diver, and a pretty full BCD is needed for balance. That extra air reacts to changes in depth, and the shallower the water, the greater the reaction. It is easy for a diver to lose control and get that unwanted and potentially fatal rocket ride to the surface. That is almost certainly why the Discover Scuba student lost buoyancy control and rocketed to the surface, leading the instructor to go after him, leaving the boy who was struggling to swim with all his weight on the bottom.

 

[Eric Sedletzky]

Yes, it can be fatal. A couple years ago an instructor conducted a Discover Scuba class for boy scouts, and the divers were about as overweighted as Ayisha describes in her post. One of the students died after the instructor left him alone while going to the surface in shallow water to tend to someone who lost buoyancy control and surfaced. The actual reason for the death is not clear, but he did appear to have trouble staying off the bottom with a full BCD.

A key problem with overweighting is loss of buoyancy control, particularly in shallow water. Every unnecessary pound requires the volume equivalent of about 15 fluid ounces of air--about a pint--to balance the extra lead. Put enough extra lead on the diver, and a pretty full BCD is needed for balance. That extra air reacts to changes in depth, and the shallower the water, the greater the reaction. It is easy for a diver to lose control and get that unwanted and potentially fatal rocket ride to the surface. That is almost certainly why the Discover Scuba student lost buoyancy control and rocketed to the surface, leading the instructor to go after him, leaving the boy who was struggling to swim with all his weight on the bottom.

I have another incident for you that happened in San Diego off a beach several years ago. Two guys do a beach dive. While they were out the conditions picked up and the surf had risen to a challenging level. They sat outside the surf zone to assess the situation. They realized it would be every man for himself and then decided to just go for it - see you on the beach. One diver made it the other didn't.
They found his body in the surf zone less that 50 feet from shore in 10 or 15 feet of water.
The conclusion:
The team that investigated to fatality found the inflator elbow on his BCD unit broke off allowing all the air in his BC to suddenly escape. They also determined that the diver was so grossly overweighted that when the air escaped he dropped like a rock. They figured he panicked and couldn't find a regulator or it was either spit out or knocked out of his mouth, and for unknown reasons was unable to release any weight from his rig (probably couldn't find the releases on his integrated system during a moment of building anxiety and panic because of the turbulent water). As a result the diver drowned.

So to conclude, if the diver had been properly weighted would it have made any difference on the surface if he had air in his BC or not? I don't think it would have made any difference IF he was properly weighted and could float on the surface. Sure, he might have gotten rolled in the surf, coughed and sputtered, drank a little sea water, but I think there would have been a better possibility of him making to the beach alive and he'd be with us today.

The entire point of this thread I started is to to try and make new OW divers aware of what gross overweighting is, and what PROPER weighting looks like, feels like, and how to achieve it. Kind of a public service if you will. I'm certainly glad that experts like Boulderjohn and others who understand what proper weighting is have contributed.


And the other half of the thread is to call out instructors who still overweight students as a matter of habit or unknowingly do so because that's what they were taught by some incompetent. I hope you're reading and understanding. Overweighting IS one of the biggest plagues affecting the safety of recreational diving and needs to be corrected.

 

[Frosty]

Not necessarily. I went into my AOW wearing 24 lbs of lead in cold fresh water with a full 7 mm farmer jane wetsuit, hood, gloves, and boots, a petite female, weighing a little over 100 lbs. I did my first weighting check ever during the AOW, and sank 10 feet with an empty bc and holding a normal breath. I went to remove weight at the shore beside us and the DMC said, "It's ok, it'll even out by the end". My buddy and I did the navigation with the DMC, and she didn't like my trim, so she kept asking her husband, a DM, for more weight to hang on me in various places - totalling 33 lbs, which felt awful. My ladies BC had a lift of 25 lbs. The instructor was in the general area, within 50 feet away, with other students.
So, the point of my long story is that some students may be so grossly overweighted that a fully inflated bc cannot lift them off the bottom. And some instructors don't recognize this or don't correct it.

I use metric weights so roughly that's 15 kg of lead. Im genuinely gobsmacked that any instructor would overweight to that extent. that's like 33% of your body weight. even if you were well "rugged up"

 

[Ayisha]

I use metric weights so roughly that's 15 kg of lead. Im genuinely gobsmacked that any instructor would overweight to that extent. that's like 33% of your body weight. even if you were well "rugged up"

I should use metric too but anything to do with diving is usually imperial here; everything else, metric. Yes, that's 15 kgs.

Remember a DMC and her DM husband were the ones hanging weights on me. The instructor was across the dive site with other students also doing navigation. It's debatable whether he knew the DM was going back and forth to shore and attaching weights to me, but he should have heard the requests and seen what was going on. Once he did know how overweighted I was, he said that I needed to leave all the weights on. I told him that I sank 10 feet during the weighting check with only 24 lbs (10.9 kgs), and the DMC interjected that I needed the weights where they were for trim, and again, he said they need to stay on.

So although he didn't put the weight on me, he refused to allow me to take them off despite my protests.

I could have put in a QA if I had known what that was over 13 years ago, but the co-owner and then later the other co-owner knew about all of the events.

 

[James R]

I am a PADI instructor. I do not, ever, intentionally overweight anyone! I can tell by how puffed up someone's BCD is if (s)he has too much weight, among other ways. I do not do have my classes do skills kneeling on platform, so too much weight makes everything more difficult, not easier.

At the end of Open Water dive 1, I have them all dump their tank to 500 and do another weight check. While this isn't a requirement, I find that it makes dives 2-4 easier for the students. By the time they've spent 40+ min on dive 1 their comfort level is usually a lot higher, so a normal breath may be a real normal breath not a "as much as my lungs can possibly hold" breath.

 

[Hawkwood]

...
At the end of Open Water dive 1, I have them all dump their tank to 500 and do another weight check. ....

Goodness, I never thought of having them expel right to 500. I do it with just whatever air they had left. Thanks for that one...it's in the "toolbox" now.