Proper weighting

[jalteramore]

Is it bad or at least undesirable, to be weighed such that you have to actively swim down to submerge? I suppose that it takes more air while descending, but then you need less air in your BCD. That should make staying neutrally buoyant easier. What do you think?

 

[KenE]

At the beginning of your dive you should be sufficiently overweighted to descend without a swim down. The overweight is due to the gas in your tank that will be gone when you need to hold your safety stop. The amount of overweight is dependent on the size and material of the tank, ie. buoyancy of tank empty. You should check your weight at the end of the dive with a nearly empty tank and able to hold a safety stop. Then drop weight until you can no longer hold the stop and then add a pound or two.

If you have successfully completed this exercise and still find that you need to swim down to descend, I would suggest you work on managing lung capacity while descending. A good exhale with an empty BC should start the descent very easily. If not, you have trapped air somewhere, and the most likely is in the lungs or wetsuit.

 

[inquis]

At the beginning of the dive, yes it's a bad idea. The weight of the gas you haven't breathed yet should make the initial descent easy. If it's hard at the beginning, you probably won't be able to stay down later.

That said, people often will not exhale completely or vent their BC very well or unconsciously kick for balance or flood their wetsuit when trying to descend.

 

[Bento.Box]

It's a horrible idea.

You might not be able to do your safety stop.

With empty tanks (30 to 50 Bar), you should be able to comfortably keep station at 1.5 to 2m depth.

 

[boulderjohn]

There is no question that the more perfectly you are weighted during the dive, the easier it is to swim neutrally buoyant. The thinner the wetsuit, the easier it is to dive that way. If you are diving a 7mm suit (or more), though, you will have a problem. The amount of weight you need to descend is more than you need during the dive, when the suit has been compressed by water pressure. For that reason, some people using thick wetsuits may prefer to dive down that first few feet. It is not something I recommend.

Diving perfectly weighted brings some problems. One is that you may have trouble during the last minutes of the dive, when you have lost the weight of the air you breathed during the dive and when your wetsuit is expanding on ascent. Another problem is related to that--as you feel yourself becoming more buoyant at the end of a dive, you will have very little air in the BCD, and you may have trouble getting that little bubble of air to the best exit point on the BCD.

I therefore recommend weighting yourself a tad over perfect. You can easily dive with a few extra pounds, and that will enable you to descend normally at the beginning of a dive.

 

[jalteramore]

Thank you all for your thoughts on this matter.