Uncontrolled descent

[jonix]

We posted practically in parallel. This is basically what happened in the case I witnessed which didn't happen in Europe. Some BC brands have very slow power inflators. This doesn't matter much most of the time - it actually makes the BC easier to control, but when you need inflation in a hurry it can be critical. It's one of the things I look for when buying a BC.

maybe you could share which BC brands/models are "capable" and good to consider buying, it would be nice to know specially for newbies like me

 

[MXGratefulDiver]

I know a few stories about this.

One sounds like an urban legend to me..... It was a story I read in a British dive rag about a diver who made a descent and didn't start to compensate until he was very deep (40 or 50 metres). At that point his descent was so fast that his BCD apparently couldn't fill fast enough to stop it. In another version of this story it was a heavily laden tek diver who didn't start compensating his descent until 300ft.

R..

Not necessarily urban legend ... I know two young men who did something like this. Basically, their plan was to drop down to 120 fsw ... and in a moment of poor judgment they decided to "race" to see who could get there first. One of them didn't even begin putting air into his BCD till he hit 100 fsw ... and his BCD couldn't inflate fast enough to arrest his descent. He bounced off the bottom at 150 fsw. He was wearing a TransPac II, which has a reasonably fast inflator.

... Bob (Grateful Diver)

 

[The Kraken]

Jonix,
Research the "Buoyancy Compensators (B/C's) and weight systems" forum.

You can find a world of information regarding your interests there.

the K

 

[Tassie_Rohan]

Another story -

I seem to remember that a diver drowned a few years ago when, after a dive, he jumped from the boat to retrieve a floating object and sank like a stone: apparently he had his weight belt on but no bc/tank. He must have been seriously overweighted.

Ditching the weight belt could have helped in this situation- however I guess panic can make you forget such matters.

Cheers,
Rohan.

 

[jonix]

Jonix,
Research the "Buoyancy Compensators (B/C's) and weight systems" forum.

You can find a world of information regarding your interests there.

the K

okie, thanks

 

[FL_Chad]

Just curious - is there anything wrong with going down fast? If I am not waiting for my wife, I go down head first and use the dump with the pull string at the bottom of my bc to dump my air as I go upside down at the surface. I, fortunately, have no problems with my ears and I swim down at a decent rate. I have never even thought about this until I came upon this subject. Granted, I have not dove over 85 feet, so maybe this is only an issue in deeper water. I also dont use a whole lot of weight.

 

[Tom Winters]

I've heard of two cases of uncontrolled descent in Hawaii. One was a photographer for National Geographic who was covering the eventual destruction by lava flow of the the town of Kalapana. He was shooting lava drops in the ocean when he went from 10' to 185' in a second or two when a big flow fell into the ocean and created a massive downdraft. He knew what he was doing so he was ok.
When I worked in a dive shop, there were some maniac divers who dived with the old Scubapro 95's that weighed close to 4 tons each. That's what they felt like trying to fit them into the storage racks after I pumped them at least.
They were diving a pinnacle that topped at 185' in about 245' so you had to hit it, or else. The other guys in the boat rigged out this younger guy and fired him off the side. Because of the currents, he probably had a lot of weight on too. So he went rocketing down, and past 100' tried slowing his descent. His little bc didn't do much, and he didn't think about ditching the weight belt until he was flying past 200' and no pinnacle in sight. Being narced out of his gourd did not help.
He made it back ok - that was not his day to die I guess. He sure was a little woozy for a while.

 

[DandyDon]

Yeah, I use the dump valves to discharge air as fast as possible, but then my weight load is close enough to proper that it's a often kick at first for me to get down enough to compress my neoprene.

Not a good approach for newbies, tho. I've seen more than one jump off, over weighted and the BC air hose unhooked both, then bounce on the bottom. The last time I was at the Santa Rosa NM 84 ft deep Blue Hole - where Coloradans often go to certify, a lady did that, missed the shelve, hit the bottom, hooked up her BC and hit the UP button long and hard. She was unconscious when she popped out of the water, but revived with little harm. I've always wondered if she went back. Oh, it was her hubby who helped her gear up and buddy checked.

There are also a few areas, for example Barracuda in Cozumel, where if the currents are running just right, you can get a down current. Just move in close to the wall to get out of it.

Yeah, I thought of that one, too. Haven't hit one yet, but I keep reminding myself - it's like a rip current, swim across it (to or away from the wall) not into it

 

[OE2X]

Just curious - is there anything wrong with going down fast? If I am not waiting for my wife, I go down head first and use the dump with the pull string at the bottom of my bc to dump my air as I go upside down at the surface. I, fortunately, have no problems with my ears and I swim down at a decent rate. I have never even thought about this until I came upon this subject. Granted, I have not dove over 85 feet, so maybe this is only an issue in deeper water. I also dont use a whole lot of weight.

Are you diving solo or with a buddy other than your wife? If you are diving with a buddy you might want to think about going down at the same rate as him.

Reasons being:
If you are now at 100' and your buddy is having problems with his ears at 20' and thumbs the dive how are you going to know?

What happens if you buddy has equipment problems and you are long gone?

What if there is a surface current that stops 20' down, but your buddy is having issues near the surface? He drifts away from you at a different rate and you can no longer find him.

Best advice - descend at the same speed as your buddy and stay with your buddy. Do your best to always stay in visual contact with your buddy on your descent. What you choose to do while solo diving is up to you.

 

[JaX NeMo]

hmm... in my lessons, I was told to go down with my body vertical, release all the air, and finning upwards to control the descend. then at the bottom, slowly add air to my bcd until i m neutral.