Ankle weights

[bradshsi]

Fred R wrote: "Well, I’ll just throw in, I use ankle weights, for almost all of my 3000+ dry suit dives, and can dive three one hour 60 foot dives on a single AL 80."

That's only 16.6lbs of air per minute. Roughly 1000psi per dive at a fill pressure of 3200psi in an AL80. For an experienced diver with excellent breathing that's quite reasonable. I believe that's a SAC of about .20cuft/min on an AL80.

I calculate a 0.15 SAC for an AL80 @ 60 ft (actually 77.4 cubic ft) assuming he sucked it dry. By way of comparison the average person sleeping has a 0.22 SAC.

 

[cummings66]

The SAC conversion you did is a bit off. First a fill would be 3000 psi to start with, second a tank would hold I think 77.4 cf of air.

If you do the math and assume he has a small reserve and actually has maybe 500 psi left that gives him 2500 psi for 3 hours worth of diving at 60 feet, for and better set down, a SAC of around .12. There is nobody on Earth that has a rate that low unless their dead. Even the dead might use more air than that.

Even if he hit the surface and had no more air left in the tank he'd have a SAC of .15, again not possible IMO unless he's dead on his feet. I'm from MO and this is one of those things you'd have to show me.

By the way, I've dove with lead on the ankles and without. I prefer without but did not notice a measurable difference between them. In my book whatever you need to do to improve trim is good, if you need ankle weights then so be it. I think it's wrong however if your trim is foot heavy or if you use it as a crutch because you're afraid of floaty feet.

 

[Blackwood]

This is a common misnomer. It will not make one bit of measureable difference.

--Matt

On two identical dives it would. You said it yourself. "...this is true in a test tube." Two identical dives represent a test tube. But here's the rub: there is no such thing as two identical dives.

 

[DBailey]

Yes but not everyone can afford perfectly made custom suits. Even if they can there are still issues such as undergarment or boot composition (neoprene vs rubber etc)

Like I said, it is an option. True, not everyone can afford it, but it still means it is a valid option.

.. or more negatively buoyant. Changing fins is just changing the weight on the feet - same thing ankle weights manage.

I agree that it is adding mass/weight at your feet, but it is an engineered distribution of weight instead of slapping some lead at your ankle. Once again, it is an option.

Thats if the floaty feet is caused by air migration - it isnt always.

Once again, I haven't seen the OP dive. I don't know what is the cause of the floaty feet. Perhaps air migration is; therefore, this is listed as an option.

Thats exactly what ankle weights do - move it from the belt to a different location to help with trim.

Going back to the OP, I don't know how his/her weight is distributed let alone the rig that he/she is diving. Perhaps he/she has 3 lbs in each non-ditchable shoulder pocket. Moving those 6 lbs from the shoulders to the belt might change the center of gravity enough to solve the problem. It is an option.

Arm and leg waving and finning effort to maintain trim can use a LOT more air than the weights are responsible for so a diver in trim with ankle weights could use less air than a diver without struggling to stay flat.

I don't think I ever said that arm and leg waving was the solution. I agree that fighting to maintain trim will use more air. I also said to use ankle weights if you want to. In the end, there may just be some people that are the exception and need to use ankle weights because none of the other options work.

 

[RPanick]

I often use ankle weights, but rarely on my ankles. They hold down tarps, they keep things from blowing away, I can add two pounds to my BC pockets. Actually, I have 1 and 1.5 pound weights that I used to use.

One day I forgot to put them on and noticed my trim was better. I've left them off since then.

Best suggestion, get neutral and don't move and see where you settle. You might be able to adjust things, if not then use the weights.

 

[Santa]

All the cool kids wear ankle weights.

When diving?

 

[merlin7896]

If ankle weights add weight to your extremities, thereby increasing work and air consumption, and negativly bouyant jetfins add weight (negative bouyancy) to your extremities....does that make jetfins inherently less efficient?

 

[scubadobadoo]

Again,, IF your gear is properly sized to you, and it should be.
And IF you learn how to properly weight yourself, and you should.
And IF you learn proper technique in shifting air in the suit at will to accomodate your trim at any given time.
You should not need ankle weights. They are a crutch, that hides poor weighting and training. Or poor equipment fit. If you need them, then you most likely have issues that should be addressed. Only my humble opinion.

Actually you should also include, "If you aren't a woman," as woman frequently experience floaty legs more so than Men. That is a fact.

As for the "use or not use" debate, I don't really care what you have on while diving as long as you don't put me in any danger. I would like to see someone tell the Deep Sea Detectives gang that they have issues that need to be addressed because they are wearing ankle weights! LOL!