Buoyancy/weighting questions from a very new diver.

[ozziworld]

I have found it helps a lot to know how much weight you need to be "neutral" in different configurations starting with . . . . .

1. just you and no wet suit - some people are more buoyant depending on body configuration.
2. you + wetsuit + mask + fins
3. you + wetsuit + mask + fins + BC/reg/tank


No. 3 tends to change depending on your gear. Especially if you are diving different type/size tanks. Aluminum 80s most commonly used in tropical resorts can be up to +4lbs positive when close to empty and that is a big swing from when you start the dive at just right to 4lbs positive when you are doing your safety stop.

Over time you will have worked it all out in your head and in your logbook so any adjustments will be relative to the piece of gear you will be changing.

I have found that I dive with hardly any air in my bcd and rarely add or remove air during a dive. When over weighted, you will find you have a bubble of air in your bcd that you are now ferrying around the entire dive which costs you air/energy to push around.

 

[Akimbo]

Here is the easiest method I have found for adjusting your weight in Scuba.

1. Get a line about 20'/6M long and tie a bowline to the end. Yes, you can use any other knot to form a loop or even spice in a padeye.
2. Tie a variety of weighs, including several 1 Lb/½ Kg, to the bowline with light line. Each weight should hang 3'/1M below the bowline and be clearly labeled. They can be any lead weights, diving or fishing.
3. Mark the larger line 10'/3M from the bowline, or the depth of your shallowest decompression/safety stop.
4. Hang the line off a boat, pier, or float with the mark at the surface.
5. At the end or your dive, bleed the tank down to about 300 PSI or the lowest pressure you think you will ever have left at the end of a decompression/safety stop.
6. Weight yourself a little buoyant at the surface with all the air emptied out of your BC.
7. Swim or pull yourself down the line.
8. Relax and breathe slowly. Pick up weights until you gently float and sink cycling with your breaths. Your chest should be near the depth of the bowline. Make note of how much weigh is in your hand, unsupported by the line.

That is the minimum amount of weight you need to add for that equipment configuration. You can do this test in a swimming pool, but you need to ad 2½% for sea water.