Pull Dumps — lose them

[rsingler]

You're a big dude, Eric. With 4-5 liter lungs, you've got 11# of buoyancy adjustment just by breath control alone.
We should all be so lucky.

Did your buddy ever decide what he wants me to build him? I've got four sets just about ready to look at. PM me. My Mk5 tools are sitting by the door.

Rob

 

[BRT]

Hmm, ok.
Maybe in warm water with thinner suits it’s touchier than here using a 7 mil. I weight myself so that I’m neutral at my 15’ stop at the end of the dive with an empty tank (near empty) and a completely empty wing. This works out for me that I can float on the surface with a full tank with no air in my wing. I have to actually swim down to start my dive.
I have worn nothing but a steel 72 on a harness (no BC) in a fresh water pool with board shorts and was perfectly neutral doing doff and don skills back in the days when I was obsessed with vintage diving. I could maintain any depth just by breath control. Floating on the surface was no problem either, neutral is neutral. Compression wasn't a factor because there was no suit to compress and get heavy. With this in mind, doing a 100’ dive the same way in board shorts and no BC shouldn’t make a difference either, especially in salt water.

How come back before there were BC’s nobody ever seemed to have a problem? All this now about potential problems occuring because of faulty BC’s? They just went diving and swam around, even in thicker wetsuits, and not one BC anywhere to he found.
It’s almost like all this new gear gets invented, and then the most common sense thing like proper weighting has somehow just vaporized from todays knowledge base. Think about it.
Someone can’t overcome 5 lbs of extra!!!
Mind boggling?

Out

Go to some of the historic diving forums and look at the videos and see how they did that. Lots of time they were bouncing off the bottom. I dive with Mexican spearfishermen who use no BCDs. They go in heavy and come up with nearly empty tanks. When they quit swimming during a dive they sink to the bottom which is just how they want it. When the tanks are nearly empty they are closer to neutral.. This is simple physics, the total weight of your rig changes as you use up your air. On a steel 72, not so much. On a steel 130, a bunch.

 

[northernone]

I can't help wondering if there are more lessons to learn from this near miss.

A few things I'm curious on:

1. Was the panicked (nearly drowned) diver alone in the water?

2. Was he familiar with his equipment?

3. Why was he choosing to dive overweighted?

4. Was there detachable weight if he needed to self rescue?

5. Any history of panic attacks?

6. Did he provide any clues to what went wrong from his perspective?

7. Was the pull dump assembled correctly?

8. Was the equipment unsuitable for the environment?

I don't like pull dumps myself, but I'm wondering what other factors played into the incident other than blaming an equipment design which works well for many people when properly trained.

Cameron

Ps. Related experience. My buddy borrowed a bcd with a pull dump elbow which he was accustomed to using on his own equipment. He didn't realize it had been disabled by removing the wire (predive didn't include that dump). Beginning the dive, he pulled hard trying to deflate (thick gloves and big guy), resulting in the corrugated hose failing.

 

[KevinNM]

This thread has been educational. Are these type of pull dumps common on jacket BCs and not on wings? I have to admit I don’t think I even knew they existed!

They are very common on "normal" BDCs. Halcyon doesn't have them on their wings, and it isn't on my DGX either.

 

[KevinNM]

I had a Halcyon power inflator get stuck on me last winter. Thankfully it was just in the pool. When I took it to the shop to get fixed, turned out Halcyon knew there was a problem and replaced it at no cost.

Was that a used wing? There was an issue years ago with a particular inflator (precision something or other IIRC). I remember someone here loved them, though he admitted they were a pain to keep running. If it was a new wing that's interesting.

 

[KevinNM]

Lisa, perhaps one of the diving with disabilities organizations has a solution for this. I realize this isn't a disability, per se, but I agree it's a serious concern. Especially for a solo diver.

You could install an in-line cutoff. They are typically used for deco bottles, but they should work.

 

[KevinNM]

And that is assuming I am not near the end of a dive. By the time I grabbed the knife and sawed through the hose I’d probably already be at the surface anyway. So scratch that idea.

Bend it 180 degrees, like kinking a garden hose, would be an option. Never tried it, but it should significantly slow the inflation rate.

 

[Marie13]

Was that a used wing? There was an issue years ago with a particular inflator (precision something or other IIRC). I remember someone here loved them, though he admitted they were a pain to keep running. If it was a new wing that's interesting.

Nope, just a few months old at the time.

 

[mainedvr]

Was that a used wing? There was an issue years ago with a particular inflator (precision something or other IIRC). I remember someone here loved them, though he admitted they were a pain to keep running. If it was a new wing that's interesting.

Don't mean to get off topic, but my daughter has a Halcyon wing single and she only have a few dives on it and went to use it the other day and during the predive check the inflator stuck. Could've been a grain of salt or sand she cleans it well after each use but was wondering what year those inflators are from. This does not look any different than any other of their inflator's. Did the one you mentioned look different? This is similar to the one you can buy from DGE as a replacement.

 

[Marie13]

My wing was made in 2016. Inflator looks like the one you can get from DGX.