Weighting And Staying Alive.....

[2airishuman]

With all these weights being lost, it's funny that we don't hear about more people corking to the surface. Why? They're over-weighted to begin with. Way over-weighted to the point they probably didn't realize they lost it until they were on the boat taking them off

I would instead surmise that the weights are typically lost near the beginning of the dive, when the weight of the air in the cylinder is sufficient to allow a reasonable amount of buoyancy control to be maintained. Overweighting may certainly contribute.

There's no doubt about it: I hate weight belts. I'm shaped like a pear and they like to slide right off of me down to my ankles. I use integrated weights or a DUI harness. Somehow, in spite of how unsafe they are supposed to be, I have never lost one. Ever.

At the root of all this is an inattention to detail. You've simply got to pay attention to how your weights get clipped in, or risk losing them.

1) sample size of 1.
2) Rental gear, in daily use, without effective feedback leading to repairs in the event of emerging problems, is I think part of the dynamic.
3) Some weight pocket designs are more problematic than others.
4) Yes, attention to detail. Many divers allow the divemaster to load their weights then fail to check them themselves.

 

[kelemvor]

Before I bought steel tanks that replaced my weights I used the diverite ditchable pouches for about 100 dives.. maybe 200 if I count aquarium working dives. I never lost one. Even when I first started and was over weighted and had more weight than they were rated for in them, I never lost one.

I think it probably comes down to the same thing most dive incidents seem to involve. User error. People either aren't maintaining their gear or don't know how to properly secure the pouches (i.e. rental bcd).

Still, the people losing weights aren't dying right? Unless you've blown your NDL you can always skip the optional safety stop if you have to.

 

[Reku]

This thread is pretty interesting...

To solve my issue of weight not being secured - I switched over to storing all the weight on my back on a weight plate and I just don't eject it. ever. It's not for everyone and I'm sure some people have problems with non ditch-able weight.

That said - I'm 70% sure that the weight is falling off people because they are using rental gear that they have never used before.

 

[archer1960]

I recall having read once, that with proper weighting, at the surface, BC fully deflated, you should be eye-level with the water's surface with lungs full. Does this sound right?

That's a commonly-stated rule of thumb for a starting point, with one important caveat that you don't mention: that test needs to be done with a nearly empty tank. If you float like that with a full tank, you will be way under-weighted at the end of the dive after you've lost 5lb or more of air.

 

[Charles2]

That's a commonly-stated rule of thumb for a starting point, with one important caveat that you don't mention: that test needs to be done with a nearly empty tank. If you float like that with a full tank, you will be way under-weighted at the end of the dive after you've lost 5lb or more of air.

And I always heard that it was with a full tank and full lungs. I only tried this one time and it seemed to work. I've been told that if you take a real deep breath (in addition to your normal breath), you can displace more than 5 pounds of water.

Back to the original topic - I have also found several lead weights just laying on the bottom - suspect they must have fallen out of pockets.

 

[Steve_C]

So it is one of those days and I have nonditchable weight and am negative and need to swim my kit to the surface when mother nature says have a major cramp in your leg muscle? Not an unheard of occurrence. Seems to assume your body is operating at 100%.

 

[2airishuman]

So it is one of those days and I have nonditchable weight and am negative and need to swim my kit to the surface when mother nature says have a major cramp in your leg muscle? Not an unheard of occurrence. Seems to assume your body is operating at 100%.

Doesn't assume 100%, assumes one failure. BC failure + leg cramp = 2 failures.

Remember, balanced rig, so even without ditching, with an empty BC and full air tanks I'm only negative by the weight of the air (8 pounds max) plus the buoyancy loss from wetsuit compression (3 pounds max since I carry ditchable weight when using a thick wetsuit). Not a lot to overcome, for me a really deep breath will get me most of the way there, I can swim with one fin for a while and evaluate choices.

I dive a backplate and wing. I use a standard elbow rather than a pull dump. A complete failure of the wing is unlikely, but the most likely causes would be the inflation elbow pulling out, or a rip on the side due to contact with something sharp. Either way I should be able to find an orientation where I can get some air into the wing and get enough buoyancy to get stable. Failing that I can ditch my kit, deploy an smb, or sink to the bottom, relax and wait until enough air is depleted that I am more buoyant.

On a wall dive or in deep water I'd consider reconfiguring my kit to make some of the weight ditchable.

 

[kafkaland]

Doesn't assume 100%, assumes one failure. BC failure + leg cramp = 2 failures.

That would be cutting it too close for me. I generally assume the possibility of two failures, and I would still be able to walk away. But your mileage may vary.

 

[Patoux01]

That would be cutting it too close for me. I generally assume the possibility of two failures.

So that's your wing and a leg... and honestly, if your life is at stake and you let a cramp take it, just maybe you were in the wrong place to begin with...

 

[Neilwood]

I think a lot of the configuration details and the "single failure/multiple failure" view points depends a lot on experience and the nature of the dive.

The deeper/longer the dives, the more critical one should be with regards to the equipment. A bimble close to the surface (5-10m) which allows for a direct escape to the surface does not necessarily require the same viewpoint with regards to equipment and failure points as a deep dive to 40m where the same escape would not be possible.

While I can see the thinking behind using the technical diving mindset for all dives (for those that were trained in it), it does not make as much sense for someone who dives easy non challenging sites.

Going all the way back to the OP, I would agree that checking the security and suitability of the weighting system (ie not large amounts of the weighting being ditchable in the event of one failure) should be an important check.