BCD/Weight Belt Failure When Diving Wet

[DanLW]

As I prepare to start diving wet again, I have a question about some possible failures, and how to deal with them. They involve the issues of buoyancy lost and regained when diving wet.

I have a 5mm full suit along with a 7mm vest, diving with an aluminum backplate, basic harness (no floaty padding), and steel tank. In this configuration, I found that I needed about 20-22lbs to stay neutral.

I have two trim pockets installed on my tank strap. I plan to put 5lbs into each pocket, for a total of 10lbs, or half my weight as non-ditchable weight.

BCD Failure Scenario

Worst case scenario, I’m at 100’ and my BCD fails to inflate. Maybe it was punctured, maybe it blew a valve, whatever… it just won’t inflate.
I figure at this point, I’m going to be 10-15lbs heavy due to suit compression, which would make it hard to maintain depth and not go deeper. What is my best option?

1. Ditch all 12lbs of weight belt and watch my ascent rate carefully, expecting to become overly buoyant. Once positive buoyancy starts taking over, either A) spread out and exhale to create drag and minimize buoyancy, or B) swim aggressively down to minimize ascent.

2. Take off the weight belt, and using my Trilobyte eezy cut, slice off a weight or two so I can start ascending by swimming, expecting again to become over buoyant, and manage it as above.

3. ?

Weight Belt Failure Scenario

Let’s keep the 100’ worst case depth. Weight belt buckle fails, and I don’t catch it in time. Now I’m suddenly 12lbs buoyant.

1. Vent all air from BCD and manage ascent, as above, by either A) spread out and exhale to create drag and minimize buoyance, or B) swim aggressively down to minimize ascent.

2. ?

Discussion:
In the BCD failure scenario, I’m thinking option 2 would be ideal. A complication I can see, however, is by the time I get the weight belt off, the trilobye out, and actually make the cut, I may have already descended unacceptably deep. Whereas simply ditching the whole belt is much quicker, but will result in a harder to manage runaway ascent once my suit decompresses.

For ascent management, I’ve always read that simply spreading out to create maximum drag is best. Is this because trying to swim down doesn’t really work all that well?

 

[GrumpyOldGuy]

You should be able to swim up 10-15lbs. Its not easy and in worst case scenario (start of dive so you have the gas weight + even thicker wetsuit) it might be too difficult. In this case you inflate your SMB and deploy. You let it pull you up to to a mid depth and then pull yourself up the line. A good sized SMB will provide 20lbs+ of lift. Ditching weight underwater should not be needed.

As for the weight belt failure, metal buckles are pretty reliable. You can use 2 in-line of you want insurance. Flare and exhale is your best bet. I have done a surface stop swimming upside down, but I was only a few pounds light.

 

[Eric Sedletzky]

A 5 mil suit with a 7 mill vest isn't that big of a deal and don't see how it would be that hard to swim it up with no air in your BC.
Dumping weight depends on how long you've been at 100 feet. If you've been down there for 15 or 18 minutes then dumping weight wouldn't be a good idea. If you've only been there for 1 minute then it would be more doable without getting hurt, but still not a good idea in my thinking.
I would make sure I had as much weight shaved off me as possible by doing the neutral at 15 feet with near empty tank and completely empty BC trick.
Then you might want to practice trying to swim up all your weight from 100 feet and see if you can do it.

 

[TSandM]

If your max lift loss from your suit is 20 pounds or less, and you have 10 pounds on your back, if your BC totally fails, you will be negative 10 lbs plus the remaining gas in your tank, or really no more than about 15 lbs. As stated, you should be able to swim that up, especially if you keep your lungs pretty full. Another option would be to carry a lift bag that you can inflate.

If you lose 10 or 12 lbs of weight, you have a problem. You can go head-down and kick down and really slow your ascent that way. But 12 pounds positive, you are likely going to the surface. If you keep breathing and you stayed well within NDLs, it shouldn't be a major issue. But this is one of the reasons I really like my Mako freediver's weight belt -- it has a tongued buckle closure, and it is EXTREMELY unlikely to come off.

 

[DanLW]

You should be able to swim up 10-15lbs. Its not easy and in worst case scenario (start of dive so you have the gas weight + even thicker wetsuit) it might be too difficult. In this case you inflate your SMB and deploy. You let it pull you up to to a mid depth and then pull yourself up the line. A good sized SMB will provide 20lbs+ of lift. Ditching weight underwater should not be needed.

As for the weight belt failure, metal buckles are pretty reliable. You can use 2 in-line of you want insurance. Flare and exhale is your best bet. I have done a surface stop swimming upside down, but I was only a few pounds light.

Ah, good point with the SMB. I have a 6' SMB, so that should provide a good amount of lift. So I basically just have to swim up long enough to deploy, and of course, I would simply leave it clipped to the reel.

A 5 mil suit with a 7 mill vest isn't that big of a deal and don't see how it would be that hard to swim it up with no air in your BC.
Dumping weight depends on how long you've been at 100 feet. If you've been down there for 15 or 18 minutes then dumping weight wouldn't be a good idea. If you've only been there for 1 minute then it would be more doable without getting hurt, but still not a good idea in my thinking.
I would make sure I had as much weight shaved off me as possible by doing the neutral at 15 feet with near empty tank and completely empty BC trick.
Then you might want to practice trying to swim up all your weight from 100 feet and see if you can do it.

Ok, I see what you mean with time being a factor. If I've already been down, I'll have all that extra nitrogen, and the risk of DCS would be much greater with a too fast ascent.

I did do a weight check in a pool. Toward the end I ended up needing about 22lbs to get down below the surface on a full exhale. As I understand, a wetsuit loses almost all of it's buoyancy at 100'. (I'm not currently planing to dive that deep, I just picked that number as a good upper (lower?) limit) So in the case of a catastrophic BCD failure at depth, I'd be faced with having to swim up 20lbs of gear.

I'll be doing my rescue diver training soon. I wonder if swimming up 1/100th of a ton of weight will be one of the drills. Perhaps I can ask my instructor to include it, as it would be good to know if I can do it. The difference will be where I'm at now, I'm not wearing a wetsuit, (water temp is 81F at 80') so I won't have that steady regaining of buoyancy to help me out.

EDIT: I just thought of a 3rd option for the first scenario - grab onto my buddy and use his working BCD to get us both back up!

 

[Eric Sedletzky]

I had to stop on my other post before I was done so I'll complete what I wanted to say here.

Regarding weighting with a wetsuit.
I've been diving wet for years in very cold water with a variety of different suits from super thick commercial suits to light weight spongy thin suits for warmer water so I know something about wetsuits and buoyancy.

There is no way to get weighting any closer than this: At the end of the dive at 15 feet (5 meters) you should be able to maintain a stop with an almost empty tank (or your personal favorite ending PSI) with your BC completely empty and sit there without finning to stay at 15 feet and be able to control your stop with breathing alone. This is as good as it gets. Forget about any checks before you start the dive with exhaling or water at eye level. All this is irrelevant, it all centers on the weighting at the end of the diove at 15 feet.
If you are light on the surface at the beginning of the dive with your weighting tuned to 15 feet then you might have to flip over and go down head first until you get neutral. But this is easy with a wetsuit, and more dynamic styles are possible diving wet because you don't have to manage a bubble like in a drysuit.

Regarding your weightbelt, there is no reason one should ever lose a belt. In tech diving this isn't an option, it can be a death sentence. If you follow a few rules, losing a weightbelt should never happen just like running out of air should never happen.
First, I use regular weight belt webbing. I don't trust rubber belts, I've had them tear in half just picking them up. All it takes on a rubber belt is for there to be one small nick on the side and they let loose and tear in half instantly. I'm also a freediver and we use rubber belts for that. I've never had one tear while freediving yet, but it would not be a catastrophic either freediving.
Stick with regular woven weight belts. Second, use a high quality stainless buckle, and if you're really worried about it you can run two stainless buckles in line.
And the last measure of security to never part with your belt unintentionally at depth is to use a crotch strap. If the belt ever somehow did come loose it would be caught by the crotch strap and you would still have it.

One last thought. I know divers that use 7 mil suits and scuba dive with no BC down to 100 feet all the time hunting lobsters in Southern California, so it can be done. It's all about proper weighting and making sure you're not dragging around extra weight you don't need. BC's have a way of masking the problem of diving overweighted.

 

[DanLW]

I HATE it when I take the time to type out a thoughtful reply just so the forum can error out when I hit post. I need to get in the habit of copying everything before posting…

There is no way to get weighting any closer than this: At the end of the dive at 15 feet (5 meters) you should be able to maintain a stop with an almost empty tank (or your personal favorite ending PSI) with your BC completely empty and sit there without finning to stay at 15 feet and be able to control your stop with breathing alone. This is as good as it gets. Forget about any checks before you start the dive with exhaling or water at eye level. All this is irrelevant, it all centers on the weighting at the end of the diove at 15 feet.
If you are light on the surface at the beginning of the dive with your weighting tuned to 15 feet then you might have to flip over and go down head first until you get neutral. But this is easy with a wetsuit, and more dynamic styles are possible diving wet because you don't have to manage a bubble like in a drysuit.

This is essentially what I did in the pool, albeit not at 15 feet. When I was near the end, I found what weight I could still go down with. I’ll re-check once I get back home, though.

Regarding your weightbelt, there is no reason one should ever lose a belt. In tech diving this isn't an option, it can be a death sentence. If you follow a few rules, losing a weightbelt should never happen just like running out of air should never happen.
First, I use regular weight belt webbing. I don't trust rubber belts, I've had them tear in half just picking them up. All it takes on a rubber belt is for there to be one small nick on the side and they let loose and tear in half instantly. I'm also a freediver and we use rubber belts for that. I've never had one tear while freediving yet, but it would not be a catastrophic either freediving.
Stick with regular woven weight belts. Second, use a high quality stainless buckle, and if you're really worried about it you can run two stainless buckles in line.
And the last measure of security to never part with your belt unintentionally at depth is to use a crotch strap. If the belt ever somehow did come loose it would be caught by the crotch strap and you would still have it.

That’s pretty much what I have: a 2” nylon web belt with stainless steel buckle. I’m not sure if it’s high quality – the price suggests not: $3.25 from Divegearexpress.com: Slide and Quick Release Buckles - Dive Gear Express

I do have a crotch strap, but I put my weight belt over it to make it easier to ditch if necessary. I suppose I could use an inner tube rubber band (a piece cut out from a bicycle tire inner tube) to put over the buckle as extra security. I haven’t had any problems with the buckle, I’m more thinking of insurance.

But ditching weight brings me to my next question. I seem to read an undertone through your and other posts that it is never appropriate to ditch weight. Is this correct, or am I reading too much into it? One school of thought seems to be along the lines of it’s better to be on the surface with DCS than on the bottom with no air (at least, eventually with no air). The other school of thought seems to be along the lines of it is never appropriate to ditch weight, and proponents of this even go as far as to use V/P weights and the like to eliminate any ditchable weight.

So while I will search, I’ll also ask here: is it ever appropriate to ditch weight? Should it be reserved for the last thing one does before blacking out, or are there extreme situations where everything goes sideways, and the only option is to ditch weight?

One last thought. I know divers that use 7 mil suits and scuba dive with no BC down to 100 feet all the time hunting lobsters in Southern California, so it can be done. It's all about proper weighting and making sure you're not dragging around extra weight you don't need. BC's have a way of masking the problem of diving overweighted.

Wow, that’s good to know. Still, I’ll ask my instructor if I can do a practice ascent with 8-10kgs of extra weight. In my current diving location, I only need 2kgs, although I could probably get away with just 1kg, and we are not wearing wetsuits. (81F at 80’!) I think it would be good for me psychologically if I knew I could swim up that much weight. Of course, in this water, it would be 10kg all the way up, whereas in a wetsuit situation, I would be progressively less overweight as I ascend.

Thank you for the thoughtful comments! I love discussions like these because I like to have this information in the back of my mind so I have something to fall back on if (when?) things go south one day.