Oor article I used to be an air hog until I found out that I am overweight
I used to be an air hog, but now I am just an air piglet
---------- Post added July 29th, 2013 at 01:00 PM ----------
It's hard to know if or how much you are "overweighted". A lot depends on how much muscle vs fat you are carrying as well as if you are diving with aluminum or steel tanks (and salt/fresh water & mil of weightsuit - as you have identified). Also, it depends on what you are doing at what depth.
I am 5'10", 200 lbs and dive at the present with 20 lbs with hp 3442 steel 100s with a farmer john 7mm suit in salt water. To some (especially tropical aluminum tank divers) it might seem that I'm overweighted, I spear fish & crab at 15' to 50' (during the same dive) and therefore my weights need to hold me steady when much nearer the surface, but are a bit too much when near the bottom. Also, I dive with a buddy (aluminum tank) who has some buoyancy issues and more than once I have grabbed him to hold him down (and let air out of his BCD) near the end of the dive. (He's learned a lot, but that's another issue.) This is why instructors/DM are many times purposefully overweighted.
Back to the fat/muscle ratio. A couple of years ago, due to some health/medication issues, I put on a lot (20+ lbs) of weight in a hurry. As I got off the medication, I found that for every 5lbs of fat I could shed, I could drop about 1 1/2 to 2 lbs pounds of lead!!!
About dropping one weight from an integrated BCD. I would suggest that you try this before you depend on it. Dropping one weight of the two BCD weights can spin you around (because you're "unbalanced") which is quite messy underwater and possibly deadly when on top (don't panic - just slip out of your BCD). It would be one way of dumping part of your weights for an ascent, but I would practice with a friend (to watch and possibly "save" you) what it is like for you when on the surface. My experience is that it is OK when I'm in an upright position, but difficult in other positions.
About fins. Some fins sink and others are buoyant. This can make a big difference. I found this out when practicing "losing both my fins" (like getting on a dive boat when they reach for your fins and you get knocked back in the water). I am perfectly balance in the water when I have my fins on. Without the fins, I am helpless - it's scarey !!! I know that I would have to quickly exit my BCD if I lost my fins because I get flipped which leaves me face down in the water. Again, only try this with a friend helping.
I want to reiterate the importance of a buddy standing by while you do these things. I've learned the "hard way" and ended up in a few very dangerous predicaments. As in any diving skill - practice practice practice, because what you have learned and practiced is what you will do when under pressure in an emergency.
I hope these comments about "weights" are helpful to you and others.
Its so critical to note down all your changes for the dive;
steel/aluminium tank
wetsuit/boots/hood
Additional waterproof containers
sling tanks
Varying these things changes your buoyancy, and when you get the weight near right, any small changes in this area can affect you. And don't forget (as its so easy to), when your tank air runs down so does your weight, in particular aluminium tanks (yes they do float when empty and most people don't realise that).
Add a hood, change the thickness of boots or wetsuit and your buoyancy changes. Often its easy to get used to a setup and be happy with your weight then in a rush of the moment add a sling tank and wonder why you are heavy (but remembering if you drain it of air, it may then be buoyant).
For me with a
6.5 mm wetsuit/boots/hood/BCD and alum tank - 23 lb
3 mm wetsuit/boots/BCD alum tank - 6 lb
6.5 mm wetsuit/hood/wing, twin steels, 7 litre alum sling tank, - 3 lb
3.5 mm wetsuit/boots, twin steels, 7 litre alum sling tank - 0 lb and heavy
So one can see any changes means reweighting at the start of the dive but keeping the end of the dive in mind. With an alum tank you should be a little heavier at the start and hopefully this is counteracted at the end with low air in your tank.
Experiment and write it down.