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When I first started out I was nearly identicle to you in build and equipment. I found I needed 10Kg (22Lb), but body fat, wetsuit type etc all affect the final figure.
A basic boyancy test is to put all your kit on and let all of the air out of your BC. Now with your reg in your mouth and vertical in the water, completely exhale. You'll sink a little, then bob up, down, up, down, but over 20 seconds or so you will find a stable point at which you tend to float.
If you're weighted right, you should float with the water at eye level.
A basic boyancy test is to put all your kit on and let all of the air out of your BC. Now with your reg in your mouth and vertical in the water, completely exhale. You'll sink a little, then bob up, down, up, down, but over 20 seconds or so you will find a stable point at which you tend to float.
If you're weighted right, you should float with the water at eye level.
I think that advice is a little wrong! You should do as suggested, but fully inhale. If ideally weighted, you should float roughly at eye level with a lung full (not painfully so, just a normal breath) and sink when you exhale.
If you want to be most accurate, do the check with an almost empty (as in end-of-dive) tank and in sea water. But you can extrapolate for both those if you do the test with a full cylinder in a pool. Have someone pass you weights (put them in pockets for speed) until you get the eye-level thing sorted.
For extrapolation purposes (if you do the check in a pool with full AL80), a rule of thumb is to add 4lbs for salt water and another 4lbs to compensate for the extra buoyancy of the AL80 as it empties. Better to do the check in the sea though, and at the end of a dive (so the tank is emptier).
Not sure about the math but I am close to the same build as you but I have al tanks and not steel.
I started out using like 14/16 pounds and couldnt descend hardly at all, I figured out if I flood my wetsuit before attempting to dive made a world of difference for me and am now down to 8 or 10 pounds,
This is just me and I am sure someone on here has a different point of view but the less added weight I have the easier it is for ME to stay neutraly buoyant..
Ofcourse ya know in saltwater you have to add some weight..
I listened to alot of folks about weighting and such but I just had to spend a day diving and fooling with the weight to get the desired effect..
Hope this helps
Ron
I think you've gotten good advice so far. 10-15% of your body weight with the exposure suit you are going to use should get you "in the ballpark". Then you need to do a bouyancy check in the water (already described above), both before the dive, and again at the end of the dive at your safety stop with tank emptied to about 500 lbs or so.
My only other suggestion is that when you are new to diving, you should do the initial surface buoyancy check without the extra gear (light(s), camera, etc.) so that you can determine a good "baseline" ballast requirement. Otherwise, if you've determined your ballast requirement while loaded down with a few pounds of gear, then do a dive and don't take the extra gear (or lose it during the dive!!), you may find yourself too "light" at the safety stop with a near-empty tank.
All good suggestions here. But I don't understand why you were not able to figure this out for yourself. This is basic stuff that should be covered in every OW class.
I think that the starting out weight for a 7mm-suit diver is 15% of the body weight plus 6-lbs. Try it from there and add or remove weight as needed.
That's what the guy above your post did and had a difficult time sinking....for a 70lbs man, that calculates to 16.5lbs. I think that will be enough, but for a new diver, you need more. I would recommend he start with 22lbs and then work it down from there.
Alternatively, tie all your gear in a knot, attached enough weight to it to keep it 1ft below the water level, add 5lbs for ocean water and there you go...
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Originally Posted by Adelaide Jay
