How to correct if you're overweighted?

[drmobil2002]

My wife and I both have found that the dive shops tell you to buy 10% of your weight, but both of us have found that you need 5% of your body weight in fresh water and 8%-10% in saltwater. This could be slightly different for others, but pretty close starting point. These numbers are based on no wet suit, diving in summer time with aluminum tanks.

Hope this helps

 

[DA Aquamaster]

Thanks everyone for your input. This is very educational. One more question....does the type of tank (steel or alum) and size have anything to do with it too?

guymenton,

Not pretending to be an expert here, but since no one else answered your question: Yes, the size and material of a tank will make a difference. In my area, when you switch from an Aluminum 80CF tank to a steel tank, you use 4 - 6 lbs less weight. That would get you in the ballpark.

I have only used steel tanks a couple times so I won't swear by the numbers. Others here should be able to give you more exact details.

A generic steel 72 requires about 4 lbs less weight than a generic AL 80.

But all steel tanks are not created equal. A Faber steel 72 for example is 6 pounds negative when empty compared to a generic AL 80 that is about 4 lbs positive when empty.

So if you normally dive with an AL 80, you would need to remove 10 lbs of weight when diving with a Faber steel 72 to maintain the same bouyancy at the end of the dive.

To make it more confusing, not all aluminum tanks are created equal in terms of bouyancy either. Even AL 80's can vary as you can encounter the standard AL 80 that is 4 lbs positive when empty or you could encounter one or more of the heavier AL 80 styles that are either 2 pounds positive or neutral when empty.

The following link gives various tank specifications and can help in figuring how your bouyancy can change and perhaps help you decide what type of tank may be right for you.

http://www.diverlink.com/gear/tankspecifications.htm

 

[xSandman3]

I'm newly NAUI O/W certified, and for weighting, I've been using the 10% bodyweight + 10 formula we were taught. But this is probably an overestimate. I'm thin (5'7", 130lbs) and diving with 24lbs with a 7mm suit. How do I find out how much extra weight I can shed?

At the end of a dive with 500psi left, and no air in my BC, I should be neutrally buoyant at 15fsw right? So, at the end of the next dive, should I dump all my BC air, and start handing weights over to my buddy until I start hovering off the bottom?

I was taught 10% of body weight with a 7mm wetsuit (CA diving ain't warm), and to add 6# for salt water. This formula works perfectly for me with a hood, but I have to add 2# when I use my hooded vest. At 6', 200lbs, I use 26#, and have never felt over or underweighted.