Ditching weights if you have no weights

[OE2X]

Thanks for all the thoughtful replies. To clarify, I only dive with one 120 at a time. Even so, the tanks is 12 - 14 lbs negatively bouyant which means that I dive with only four lbs in my weight pouch.

My question concerns the situation where all other emergency bouyancy efforts have failed and you just have to ditch your weights on the surface to remain bouyant. Given the fact that in a number of fatal accidents the diver failed to ditch his weights it made me wonder what do you do if you reach the surface, have to ditch some weight, and really have no ditchable weight to drop.

Thanks...

When you get to the surface ditch your tank. In a rescue class you are taught to do this with an unconscious or non breathing diver. Depending on your harness system, it may be faster to cut your way out. Unless you are solo diving, your buddy should also be able to help you remain positive as well as get out of your gear.

 

[OE2X]

Just out of curiousity.
Are the tanks 12-14 lbs. negative when full or with 500 psi in them?

Oren - Good Question. According to the fact sheet at Diver Discount the HP120 is -18.1 when full and -9.2 when empty.
http://www.diverdiscount.com/tankspecifications.html

 

[VaDiver]

With 500 psi....

 

[jbd]

My question concerns the situation where all other emergency bouyancy efforts have failed and you just have to ditch your weights on the surface to remain bouyant. Given the fact that in a number of fatal accidents the diver failed to ditch his weights it made me wonder what do you do if you reach the surface, have to ditch some weight, and really have no ditchable weight to drop.

Thanks...

As noted by OE2X in post #11 once at the surface ditch the 4#'s and if necessary ditch the rig.

 

[jerryn]

Sorry about thinking they were doubles. I just assumed when you said you bought two of them. Makes a nice set of doubles though.

Then the question becomes, at the beginning of your dive you have a buoyancy failure and perhaps another problem and must surface what do you do? Others have suggested that when you get to the surface you ditch your tanks if need be. To see if this is an option, fill your tank, go to the bottom of a pool. deflate your wing and swim yourself to the surface. Then tread water on the surface while you get out of your rig. If this is no problem that is the answer.

Oft times in accidents the victim surfaces but is unable to stay on the surface and sinks back down. If you find you cannot comfortably remove the tanks so that you can stay at the surface, redundancy is the only answer.

Jerry

 

[ifukuda]

VA,

Assuming that you are perfectly neutral at the surface with an empty tank, you'll be 9lbs negative when your tank is full. You should plan accordingly.

 

[Grey_Wulff]

I would have thought some form of ditchable weight was essential for certain emergency situations.

Consider the dive accident detailed in the December '04 Scuba Diving magazine. If you have not read the article the basic story is as follows. The diver in question enters the water with a hidden gear malfunction (BC inflator valve was broken). His buddy was already in the water and had moved to the anchor line. On entering the water, the valve immediately fails and with insufficient air in his BC the diver starts to sink. The diver continues to struggle to inflate the BC, plummeting 160ft before grabbing onto the wall they were diving. At this point, he evidently attempted to ditch his weights (one weight was found partially out of its pocket) but unfortunately he was out of air and drowned before completing the task.

Clearly, a number of factors probably contributed to this accident (entering the water without a properly inflated BC, one buddy moving to the decent line and being to far away to help, incorrect maintenance of equipment) but had the diver ditched his weights he might well have survived.

Thus, I think some ditchable weight is absolutely essential. I'm certainly not saying making a rapid assent is 'optimal' but at least a diver on the surface can be treated for any resulting medical conditions.

Grey_Wulff

 

[RiverRat]

I would have thought some form of ditchable weight was essential for certain emergency situations.

Consider the dive accident detailed in the December '04 Scuba Diving magazine. If you have not read the article the basic story is as follows. The diver in question enters the water with a hidden gear malfunction (BC inflator valve was broken). His buddy was already in the water and had moved to the anchor line. On entering the water, the valve immediately fails and with insufficient air in his BC the diver starts to sink. The diver continues to struggle to inflate the BC, plummeting 160ft before grabbing onto the wall they were diving. At this point, he evidently attempted to ditch his weights (one weight was found partially out of its pocket) but unfortunately he was out of air and drowned before completing the task.

Clearly, a number of factors probably contributed to this accident (entering the water without a properly inflated BC, one buddy moving to the decent line and being to far away to help, incorrect maintenance of equipment) but had the diver ditched his weights he might well have survived.

Thus, I think some ditchable weight is absolutely essential. I'm certainly not saying making a rapid assent is 'optimal' but at least a diver on the surface can be treated for any resulting medical conditions.

Grey_Wulff

I'll have to dig up the article. It sounds to me like this guy was grosly overweighted.
You only need to "overweight" yourself to compensate for the gas you plan (or not plan,such as an emergency) to use. If you are divng close to neutral then some fin kicks and a lungfull of air should start your ascent. You should not really sink until you exhale with an empty BC. You should not sink like a stone even without air in your BC.
This varies of course depending on variables such as, single or double tanks (more buoyancy "swing"), stage bottles, wetsuit thikness, drysuit etc. When I dive wrecks in NC I use an AL backplate, SS tank and 4# on my belt in a 3mm shortie. I use no air in my BC at the surface at the start of the dive and very little during the dive at depth.
With my 7mm full suit it's a little different story as I have to use the BC to compensate for significant suit compression. Even so I can swim up my single SStank rig without the BC. Ditching 3# - 6# would give me a little more of an edge. Ditching weight would have saved this guy BECAUSE he was probably overweighted. Again, I'll see if I have the article.

 

[Grey_Wulff]

I'll have to dig up the article. It sounds to me like this guy was grosly overweighted.
You only need to "overweight" yourself to compensate for the gas you plan (or not plan,such as an emergency) to use. If you are divng close to neutral then some fin kicks and a lungfull of air should start your ascent. You should not really sink until you exhale with an empty BC. You should not sink like a stone even without air in your BC.
This varies of course depending on variables such as, single or double tanks (more buoyancy "swing"), stage bottles, wetsuit thikness, drysuit etc. When I dive wrecks in NC I use an AL backplate, SS tank and 4# on my belt in a 3mm shortie. I use no air in my BC at the surface at the start of the dive and very little during the dive at depth.
With my 7mm full suit it's a little different story as I have to use the BC to compensate for significant suit compression. Even so I can swim up my single SStank rig without the BC. Ditching 3# - 6# would give me a little more of an edge. Ditching weight would have saved this guy BECAUSE he was probably overweighted. Again, I'll see if I have the article.

There was no indication in the article that he was grossly over weighted, but the diver was obviously carrying enough weight that upon entering the water without his BC partially inflated he started to descend - probably at a normal rate at first. Of course as he got down deeper, compression of his suit, etc. would then have increased his negative buoyancy and the runaway decent would begin. I guess in the panic or preoccupation of trying to inflate his BC it did not occur to him to ditch his weights.

If you had no weights to ditch in this situation, you would have one less option to recover. Your only hope now would be swimming up or inflating the BC. The BC would not inflate in this case because of the type of failure and the same failure was causing him to deplete his air rapidly.

Anyway, food for thought.

Grey_Wulff

 

[MikeFerrara]

There was no indication in the article that he was grossly over weighted, but the diver was obviously carrying enough weight that upon entering the water without his BC partially inflated he started to descend - probably at a normal rate at first. Of course as he got down deeper, compression of his suit, etc. would then have increased his negative buoyancy and the runaway decent would begin. I guess in the panic or preoccupation of trying to inflate his BC it did not occur to him to ditch his weights.

The indication that he was overweighted is in the fact that he apparantly was unable to get or stay at the surface by swimming. You should only be heavy by an amount equal to the weight of the air that you carry. For all those diving an 80 cu ft tank that means they should never be more than about 6 pounds negative. So...carry 4 pounds or so of ditcheable weight if you want.

If you had no weights to ditch in this situation, you would have one less option to recover. Your only hope now would be swimming up or inflating the BC. The BC would not inflate in this case because of the type of failure and the same failure was causing him to deplete his air rapidly.

Anyway, food for thought.

As you mentioned things get worse at depth if suit compression is a factor which is one very good reason why heavy wet suits are a lousy choice for deep dives. But...if you drop weights at depth you'll have the oposite problem on ascent because that suit will expand increasing your ascent rate possibly making you the first civilian to make a moon landing.

Don't dive too heavy and don't have more ditcheable weight than you need. I've seen many more divers unintentionally drop weights and shoot to the surface than I have seen stuck at the bottom.

As usual, it sounds like Rodales missed the real points.