It does us all good to reflect that things we do almost instinctively are in fact learnt. Once you get some experience you hardly need to think about correct weighting. It becomes second nature. When starting out it can seem like some great mystery. Bit like riding a bike really, when you can do it you can't understand how you or others couldn't.
Anyway back to correct weighting. Factors are not so much your size but how you're built and what suit you wear. Thin people generally need less weight while us fatties need more. Basically muscle and bone are more dense than fat and produce less upthrust (floatation) for their volume. The suit provides the main buoyancy though. A 3mm shorty needs a kilo whereas a full 7mm suit needs several kilos. I've also found that there is an "X" factor. Some people in some suits just seem to float more. Could be lung volume or even "wind"
.
If you only ever swum on the surface then that would be it but when you dive it gets more complicated. As you descend the increasing water pressure compresses your suit and your lungs. You therefore loose buoyancy as you descend.
So there are far too many factors to have a working formula. Make an estimate and then carry out some experiments.
Dive to different depths and try to hover in the water, staying still. It's best to do this using a rope line or next to a wall etc. If you float up you're positively buoyant, if you sink you are negative. Find the point at which you remain still. That is your neutral buoyancy for that weight.
By adding or removing weights your neutral buoyancy depth is altered.
For general fishing in 1m to 10m depth I weight for neutral buoyancy at 6 or 7 metres.
Hope your English can cope with my explanation. It's got to be better than my German. :t
Cheers
Dave
Ps To go up is to "ascend" (never ask an American about the English language). They can't even spell "colour" for heavens sake!
