Ditching weights if you have no weights

[VaDiver]

Last summer I bought two Faber steel HP120s primarily for use on NC wrecks. If you have ever lugged one of these cylinders onboard a boat you know how heavy they truly are. I think B-17s used to drop them over Europe during WWII. Trying to figure out the optimum weight took several dives of different weight configurations. Finally, I figured out that the tanks are about 12-14 lbs negatively bouyant which meant that with my wetsuit, hood, camera, etc I needed to stuff an extra four lbs in my pouches, far less than what I carry with aluminum tanks. In freshwater, or with a lighter suit I would probably need still less weight.

My concern is this: with the tank so negatively bouyant, and with me carrying only four lbs (or less) of extra weights I really don't have much to ditch in the event of an emergency. It occurs to me that tanks these heavy are actually a liability in situations where bouyancy becomes a critical situation. Simillarly, if you are someone whose bouyancy allows you to dive with no weights, what do you do if you have to ditch something?

Any comments from someone who has also considered this issue would be greatly appreciated.

 

[WaterDawg]

Good question. One that many folks never really ask them selves. Some folks sugest ST tanks be dove w/ a dry suit, could they be on to something?

 

[OE2X]

The way I dive with a crotch strap, my 8# of weight are not easily ditchable. I have a BP and STA totaling 16 #. I haven't seen the need to ditch weights. I dive dry with steel 130's, so I have built in redundancy if my wing goes. If all else fails, I would depend on my buddy and his wing to help me ascend.

Under what scenario are you thinking you need to ditch weights?

You should be able to swim your rig to the surface if weighted correctly. There you can ditch your whole rig. It is only on the surface that I can see myself ditching weights or my rig to float.

 

[Doc Intrepid]

My concern is this: ...with me carrying only four lbs (or less) of extra weights I really don't have much to ditch in the event of an emergency. It occurs to me that tanks these heavy are actually a liability in situations where bouyancy becomes a critical situation. Simillarly, if you are someone whose bouyancy allows you to dive with no weights, what do you do if you have to ditch something?

You plan your dive and dive your plan in a manner such that you factor in the fact that you have very little to no ditchable weight.

For example, first you plan redundant bouyancy. It can take the form of a drysuit, although drysuits are best used for thermal protection, they do a poor job of providing bouyancy - not being designed to do so. It can also take the form of a liftbag or SMB.

The second and more important consideration, however, is that you ought not to be responding to an emergency alone. You should have a buddy. You and your buddy ought to have discussed what might occur, and should be situationally aware of each other to the point that sudden distress on the part of one elicits a response on the part of the other.

Ditching weights can be counter-productive because, depending on your dive profile and the nature of the emergency, rocketing upward like some recently launched polaris missile is seldom the optimal response. So long as you are breathing, even from your buddy's secondary second stage, a slow, controlled ascent is preferred. If you ditch your weights, but you need them to maintain equilibrium as your wetsuit expands during your ascend up through 30', you may be unable to control your rate of ascent to the surface. Again, depending on how long you were down, and how deep, this could be problematic.

It is a matter of how you approach dive planning, gas planning, and emergency response planning. Generally speaking, ditching your weights is not the optimal response for each and every emergency you may encounter. In fact, when you consider the matter, ditching your weights is very rarely the OPTIMAL response for any emergency you may encounter. Diving such that you stick with your buddy, and relying on your buddy, is likely to be a much safer option in nearly all cases.

FWIW. YMMV.

Doc

 

[OE2X]

Doc - you are a man of eloquence. You said all that I wish that I had. Thank you for filling the void that I left. FWIW - excellent post.

 

[jerryn]

My first question is why do you need 240 cu ft of gas if you are not doing technical dives? If you are doing technical dives, then you need to, among other things (as Doc suggested many other things only some of which he innumerated), have redundency in your systems.

When I dive without ditchable weights, I am always in a dry suit, even in Hawaii. It makes the deco much more comfortable and efficient. If I am diving wet, I am configured with AL tanks or single steel tanks and require a weight belt.

Jerry

 

[diver doh]

My first question is why do you need 240 cu ft of gas if you are not doing technical dives? If you are doing technical dives, then you need to, among other things (as Doc suggested many other things only some of which he innumerated), have redundency in your systems.

When I dive without ditchable weights, I am always in a dry suit, even in Hawaii. It makes the deco much more comfortable and efficient. If I am diving wet, I am configured with AL tanks or single steel tanks and require a weight belt.

Jerry

I don't believe that what he was saying was that he was doubling those faber 120's. You'd have to be a heck of strongman to manage those beasts doubled.

FWIW, I am diving a SS B/P with STA, 3 mm wetsuit and PST 119's. I carry 0 ditchable weight, am at a total of about 15 #'s with this combo.

I am more than capable of swimming this kit back to the surface from depth with no problems.

If I was diving my drysuit, I would probably only have another 4-6 #'s of weight, 3 of which would be ankle weights and I can get rid of those easy enough.


See ya



I'd just have to dump everything when I hit the surface

 

[BigboyDan]

You plan your dive and dive your plan in a manner such that you factor in the fact that you have very little to no ditchable weight.

For example, first you plan redundant bouyancy. It can take the form of a drysuit, although drysuits are best used for thermal protection, they do a poor job of providing bouyancy - not being designed to do so. It can also take the form of a liftbag or SMB.

The second and more important consideration, however, is that you ought not to be responding to an emergency alone. You should have a buddy. You and your buddy ought to have discussed what might occur, and should be situationally aware of each other to the point that sudden distress on the part of one elicits a response on the part of the other.

Ditching weights can be counter-productive because, depending on your dive profile and the nature of the emergency, rocketing upward like some recently launched polaris missile is seldom the optimal response. So long as you are breathing, even from your buddy's secondary second stage, a slow, controlled ascent is preferred. If you ditch your weights, but you need them to maintain equilibrium as your wetsuit expands during your ascend up through 30', you may be unable to control your rate of ascent to the surface. Again, depending on how long you were down, and how deep, this could be problematic.

It is a matter of how you approach dive planning, gas planning, and emergency response planning. Generally speaking, ditching your weights is not the optimal response for each and every emergency you may encounter. In fact, when you consider the matter, ditching your weights is very rarely the OPTIMAL response for any emergency you may encounter. Diving such that you stick with your buddy, and relying on your buddy, is likely to be a much safer option in nearly all cases.

FWIW. YMMV.

Doc

Best post that I've read on this board addressing a particular question. A lot to think about... learn, plan, and be aware.

 

[VaDiver]

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...

 

[aquaoren]

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...

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