Perfect buoyancy

[TMHeimer]

I heard somewhere-- "do a proper weight check then add 5 pounds", or you could do one with a near empty tank and not add 5 pounds. I've done that maybe half a dozen times over 15 years with no problems with my buoyancy.

 

[Ayisha]

...Should I try to find a 1/2 lb weight for each side?...

If you want 1/2 lb weights, ankle weights have three 1/2 lb weights. You may also be able to order 1/2 lb "chicklets".

 

[CT-Rich]

The problem with agonizing over a pound or two of weight is that it really doesn’t make a huge difference. Swap out your light or forget it in the car and decide to wear a hood or ditch the cloves and your perfect balance is toast. I plan on being a couple of pounds heavy so I am not struggling to stay down at the end of the dive, which probably wastes more air than an extra spritz into my BCD.

I borrowed an AL80 a couple of years ago and towards the end of the dive I was stressing because I could no longer maintain depth with a near empty tank. I would have used less gas with an extra four pounds of lead and would not have notice the difference.

 

[David Novo]

At times I have started dropping weight "because I can hold fine at the end of a dive". Eventually I end up light and think about how it would be if I really needed to breathe the tank down. Then I put on a couple extra pounds. I really don't notice it diving 4-5 pounds heavy.

The issue here seems to be the definition of "properly weighted". If you consider this to be able to be neutral at your shallowest stop (which seems to be 10 feet / 3m in a significant number of agencies - PADI, GUE, etc), with tanks nearly empty and the minimum gas possible in your wing, some of the described situations do not apply.

This covers both the ability to be neutral to negative (with an empty wing) at 3m independently of the amount of gas in your tank(s). If you change your configuration, just estimate what the impact will be and do a proper weight check in the end of that dive.

 

[TMHeimer]

The problem with agonizing over a pound or two of weight is that it really doesn’t make a huge difference. Swap out your light or forget it in the car and decide to wear a hood or ditch the cloves and your perfect balance is toast. I plan on being a couple of pounds heavy so I am not struggling to stay down at the end of the dive, which probably wastes more air than an extra spritz into my BCD.

I borrowed an AL80 a couple of years ago and towards the end of the dive I was stressing because I could no longer maintain depth with a near empty tank. I would have used less gas with an extra four pounds of lead and would not have notice the difference.

Yes, a couple of extra pounds certainly can't hurt. At 42 pounds and entering a shore dive with a wetsuit that is bone dry I have to completely exhale and then it is still a bit of a wait for me to descend.
As well, we all know that your buoyancy is constantly changing as you breathe your tank down. I guess you could say that at some exact point during the dive you have "perfect buoyancy". If you add 5-6 pounds doing a weight check with a full tank at the start of a dive then you are 5 pounds overweight at that time anyway. A couple of extra pounds.. eh.

 

[BlueTrin]

Yes, a couple of extra pounds certainly can't hurt. At 42 pounds and entering a shore dive with a wetsuit that is bone dry I have to completely exhale and then it is still a bit of a wait for me to descend.
As well, we all know that your buoyancy is constantly changing as you breathe your tank down. I guess you could say that at some exact point during the dive you have "perfect buoyancy". If you add 5-6 pounds doing a weight check with a full tank at the start of a dive then you are 5 pounds overweight at that time anyway. A couple of extra pounds.. eh.

Agree, also, personally at this time of the year I like to be able to hold my stop with a bit of air in my drysuit: I feel really cold if I hold it without air in my drysuit.

Dont know if this is wrong.

 

[Graeme Fraser]

At this time of the year I like to be able to hold my stop with a bit of air in my drysuit: I feel really cold if I hold it without air in my drysuit.

Dont know if this is wrong.

Absolutely right, and especially if you've got deco. I don't want sit at 6-3m for 20-30mins in 7°c water shrink-wrapped into my drysuit. Not an effecient way to wash out residual nitrogen either.

 

[RainPilot]

At this time of the year I like to be able to hold my stop with a bit of air in my drysuit: I feel really cold if I hold it without air in my drysuit.

Dont know if this is wrong.

Warm and toasty on deco is far better than futzing about over a pound or three. Another aspect of too much suit squeeze is that it may restrict circulation in the shoulders etc since you aren't moving much, and a few DCS cases I know of have been attributed to this issue. A new wetsuit that is overly tight since it hasn't stretched yet is the usual culprit.

 

[ScubaCat]

Another contingency in some situations is that a boat is turning a prop over your head. It might literally be a life or death importance to be able to hang at 10 feet and wait for two minutes with near zero air in your BC.

Exactly this happened to me last year. We’d completed our safety stop and were coming up the line to the boat. At about 2 meters we hear the unmistakable sound of a rib starting and it then spent 5 minutes or so running about untying the boat next to us. Was very grateful I didn’t have to work to stay down and could just stay there easily.

 

[BRT]

Absolutely right, and especially if you've got deco. I don't want sit at 6-3m for 20-30mins in 7°c water shrink-wrapped into my drysuit. Not an effecient way to wash out residual nitrogen either.

Another side benefit of extra air in the drysuit is when you need to dump some it is easy rather than having to work it out. Makes buoyancy adjustments a lot easier.