No Ditch-able weights with BP/W

[dmaziuk]

Tank valve entangled in fishing line, and buddy out of sight?

Depending on how much extra webbing you have, you may be able to loosen the waist strap enough to get to the valves while still being somewhat attached to the thing. (Brought to you by "some day I get a round tuit for trimming off a foot or two from my webbing".)

 

[Ayisha]

I'm sorry, but this is just wrong!
Ditching some of your wetsuit weight still leaves you negative, and you become neutral at some shallower depth, at which point you can offgas and reassess. With a balanced rig, you don't carry enough ditchable weight to give you a runaway ascent.

If you are overweighted, and dump ALL of that excessive weight, I suppose you could end up positively buoyant, but it is extremely unlikely at depth, because wetsuit compression removes your buoyancy. The question is, at what depth do you become neutral?

Reading the Buoyancy Tool thread in the Advanced Forum makes this crystal clear. I am upset that we continue to promulgate this myth.

This is not correct for the typical recreational diver. If you dive a balanced rig, you're not carrying extra weight. You are wearing the correct amount of weight from the beginning to the end of a dive. Ditchable weight is not necessarily extra weight. A recreational diver may not have the ditchable weight that a tech diver diving an unbalanced rig may have, such as a can light, heavy camera or DPV, for example, that can easily be ditched, returning to a balanced rig.

If a diver removes some weight and becomes under-weighted, at some point they will need to leave that sweet safety of neutral buoyancy and they certainly can have an uncontrolled ascent by the time they get shallower.

Removing weight at depth in a downcurrent is less effective than other strategies and can potentially cause more complications.

 

[Ayisha]

...some people can't get out of a BP/W in the water.

Then the bp/w is not correctly fitted for them. It should not be tight or hard to get into or out of, even with limited mobility issues.

 

[johndiver999]

The OP seems to be talking about a very modest amount of lead. Dropping 4-6 lbs of lead is not going to send anyone shooting to the surface and it probably won't make a lot of difference in a strong downcurrent.

When I have a choice of attaching 4-7 lbs of lead to my BC or wearing a weightbelt, I would choose the later. I think it is safer than having unditchable lead for recreational diving, If the diver is wearing a BP/W with a crotch strap, the crotch strap provides a secondary means to ensure that a weight belt is not accidentally dropped. I also find it easier on the back (when switching tanks) to avoid adding lead to the BC or harness.

 

[2airishuman]

Then the bp/w is not correctly fitted for them. It should not be tight or hard to get into or out of, even with limited mobility issues.

Yep, that's the official story.

 

[Jay]

This is not correct for the typical recreational diver. If you dive a balanced rig, you're not carrying extra weight. You are wearing the correct amount of weight from the beginning to the end of a dive. Ditchable weight is not necessarily extra weight. A recreational diver may not have the ditchable weight that a tech diver diving an unbalanced rig may have, such as a can light, heavy camera or DPV, for example, that can easily be ditched, returning to a balanced rig.

If a diver removes some weight and becomes under-weighted, at some point they will need to leave that sweet safety of neutral buoyancy and they certainly can have an uncontrolled ascent by the time they get shallower.

Removing weight at depth in a downcurrent is less effective than other strategies and can potentially cause more complications.

Perhaps have a play with @rsingler's SS tool. When I've done that for my setups the most I need to kick-down isn't much and mainly relevant at very shallow depths.

 

[loosenit2]

Agreed with jlcnuke's and pfcaj's comments. You can remove the weight pouches on the tank bands then use a weight belt. Or, you can carry a dsmb or lift bag in the storage pouch, assuming you have one on the plate, for additional lift if needed.

I've seen the suggestion of using an SMB for additional lift in two threads today. At first glance this seems a little dangerous to me. The time it takes to inflate an SMB, figure 30 seconds to 1 min is time wasted in an emergency, which is the context of the question about ditchable weight. Curious the logic behind suggesting using an SMB for extra lift in this context?

 

[PfcAJ]

I've seen the suggestion of using an SMB for additional lift in two threads today. At first glance this seems a little dangerous to me. The time it takes to inflate an SMB, figure 30 seconds to 1 min is time wasted in an emergency, which is the context of the question about ditchable weight. Curious the logic behind suggesting using an SMB for extra lift in this context?

Its not logical.

If you jump in the water and the elbow pops off your BC, the immediate direction you're going is DOWN. Unless you can swim against the weight of your gear and/or ditch enough lead to allow you to swim against the weight of your gear, you're going to continue to go DOWN. As you fatigue and your suit compresses, your rate of DOWN is going to increase. Lawn dart.

Trying to deploy some sort of lift bag or SMB when you're nosediving toward Davy Jones Locker is fantasy at best.

 

[loosenit2]

Its not logical.

If you jump in the water and the elbow pops off your BC, the immediate direction you're going is DOWN. Unless you can swim against the weight of your gear and/or ditch enough lead to allow you to swim against the weight of your gear, you're going to continue to go DOWN. As you fatigue and your suit compresses, your rate of DOWN is going to increase. Lawn dart.

Trying to deploy some sort of lift bag or SMB when you're nosediving toward Davy Jones Locker is fantasy at best.

This was exactly my thought, put much better than I did it. Open to hearing an alternative way of thinking about it.

In my mind using an SMB to create lift to counterbalance some other ditchable weight might be ok. For example if you are collecting trash/treasure in a mesh bag and you need some additional lift using an SMB might be ok (but would require practice), but only because in an emergency you can drop the mesh bag with no consequence of harm to yourself.

 

[PfcAJ]

This was exactly my thought, put much better than I did it. Open to hearing an alternative way of thinking about it.

In my mind using an SMB to create lift to counterbalance some other ditchable weight might be ok. For example if you are collecting trash/treasure in a mesh bag and you need some additional lift using an SMB might be ok (but would require practice), but only because in an emergency you can drop the mesh bag with no consequence of harm to yourself.

Right, except a lift bag is the proper tool for that. SMBs generally have a dump valve positioned at the bottom of the tube. As gas expands during ascent, the diver will have no way to dump the expanding gas manually to control the ascent.

A lift bag, in contrast, has the valve at the top of the bag. This allows the diver to vent gas as needed to maintain control.

IMO, the only argument for a SMB as lift device following a failed BC is to establish permanent positive buoyancy when you're on the surface as a matter of convenience, not necessity.