What % of your weight should be ditch-able?

[beaverdivers]

What % of your weight should be ditch-able as a recreational diver?

Certainly, tech divers doing overhead environments wouldn't want any ditch-able weight.

But, the recreational diver should have a percentage ( 100% - 10% ??? ) of their weight ditch-able.

Please post your thoughts.

 

[Steve_C]

I do not think it is fixed percentage. They should have enough ditchable so that in all circumstances they can go buoyant. Note that if they are diving a thick wetsuit or are diving in salt a lower percent needs to be ditchable.

There are two reasons to ditch. One it to go up. The other is to be able to stay at the surface. For going up you are better off being able to not ditch all of it to slow ascent.

If at the surface and waiting for help the more they can ditch the better.

 

[diver_dj]

In my usual configuration, 80% of my weight can be easily ditched. I hope I never need to actually do so.

 

[Wookie]

None of my weight is ditchable unless I choose to dive an aluminum cylinder or wear a wetsuit, neither of which I would be happy to do. I have ditched a 22 lb belt while wearing a 7 mil semi dry and I'm convinced it saved my life. I no longer dive in water colder than 80.

 

[PfcAJ]

Enough so that you can swim up with a full tank.

That way you're in control at all times.

 

[Dive Bug Bit Me]

I think it depends on the environment.

Warm water, 3 mm wet suit, AL80, I use just a steel back plate with no weights at all. Easy to swim it up.

Mild water, 5mm two piece with hood I use the same back plate and AL80. 5 kg of weight all easily ditched.

Cold water, Tri-lam drysuit, double 120s and steel back plate, I use the same 5kg of weight.

Basically my strategy is to drop just enough weight to allow a controlled ascent. In all scenarios I can swim up without ditching any weight.

 

[boulderjohn]

One of the problems with using a percentage as a formula is that so many divers are so very much overweighted. If a diver is properly weighted, then a certain percentage might be perfect. With a heavily overweighted diver, it might not be nearly enough.

Let's look at the weight check process. A properly weighted diver should float at eye level with an empty BCD while holding a normal breath. If the test is done with a full tank, some people will add weight equal to the weight of the air in the tank that will be lost during the dive. Some people will do the test with a near empty tank to take care of that.

Either way, a properly weighted diver should have a very hard time sinking if the tank is empty.

Consequently, a properly weighted diver should only need ditchable weight equal to the weight of the air in the tank being used. Every pound of weight more than that should probably be ditchable as well.

I will add that I am sympathetic to the "swim up with a full tank" argument.

 

[Jim Lapenta]

I use 2-4 lbs. at most. Often it's zero. And that is on recreational dives. Tech dives depends on situation and configuration.
A % is impractical for ditching as much as it is saying you should require a % of your body weight for total weighting. Might be starting point but is never as good as a proper check.

 

[herman]

In a rec dives, zero is needed if your weighting correct. At worst you should only be overweighted by the amount of gas you would possibly use during the dive- 4-5 lbs for an 80. I can easily swim up that much, fact is I can fairly easily handle that much overweighting with breath control alone, it's close to my upper limit but I have done it several times to learn my limits. The only use for ditchable weights is a lot of extra floatation at the surface in the rare event you will be stuck there for a long time. At that point if it becomes necessary, you could always remove your BC and dump the weights manually....or have your buddy remove them.

 

[FM1520]

One of the problems with using a percentage as a formula is that so many divers are so very much overweighted. If a diver is properly weighted, then a certain percentage might be perfect. With a heavily overweighted diver, it might not be nearly enough.

Let's look at the weight check process. A properly weighted diver should float at eye level with an empty BCD while holding a normal breath. If the test is done with a full tank, some people will add weight equal to the weight of the air in the tank that will be lost during the dive. Some people will do the test with a near empty tank to take care of that.

Either way, a properly weighted diver should have a very hard time sinking if the tank is empty.

Consequently, a properly weighted diver should only need ditchable weight equal to the weight of the air in the tank being used. Every pound of weight more than that should probably be ditchable as well.

I will add that I am sympathetic to the "swim up with a full tank" argument.

Well said and I agree. Although the weight of the air in the tank is dynamic I think its a good rule. My LP 95 is 8lbs neg full, I carry 6 lbs ditch-able.

---------- Post added October 14th, 2013 at 03:49 PM ----------

In a rec dives, zero is needed if your weighting correct. At worst you should only be overweighted by the amount of gas you would possibly use during the dive- 4-5 lbs for an 80. I can easily swim up that much, fact is I can fairly easily handle that much overweighting with breath control alone, it's close to my upper limit but I have done it several times to learn my limits. The only use for ditchable weights is a lot of extra floatation at the surface in the rare event you will be stuck there for a long time. At that point if it becomes necessary, you could always remove your BC and dump the weights manually....or have your buddy remove them.

I don't really agree with this. for example, diving the oil rigs with no bottom and usually a live drop, if you have a BC failure (inflator hose comes off) the ability to drop some weight on descent will make a big difference in being able to recover.