How Much Weight For 3mm suits?

[SubMariner]

That's not very good advice. One should be neutral just below the surface with an empty BC and near empty tank while breathing normally. Then, a diver can be sure of a comfortable safety stop and a controlled ascent to the surface at the end of a dive.

Murph was on the right track, but the explanation needs a bit of elaboration.

First, the diver should be wearing ALL the exposure protection they will using on that dive. This includes hoods, gloves, etc. Add in all the gear.

At the surface with an EMPTY BC, and a FULL lung of air, the diver should be floating at eye level on the surface. When they EXHALE, they should start to sink. If not, more lead is needed.

If the diver will be using a standard AL tank, add 3-4 lbs to compensate for the positive buoyancy of the tank with 1500 psi or less.

Again, it's not an "exact" formula, but more of a "rule of thumb". It WILL take fine tuning to get the right amount of weight to be nicely neutral.

Don't forget to note in your logbook what you wore & how much weight you needed, esp if you dive in various conditions (salt vs fresh) and exposure protections. This will help save time & effort on future dives.

DSDO,

 

[DivePartner1]

Weighting really depends on your diving style.

At 215 pounds and a 3mm shorty, I dive with 10 pounds of lead with an AL 80 in salt water. My wife--who has a thousand more dives than me -- dives with 24 pounds of lead but is smaller. Go figure.

 

[DivePartner1]

Don't forget to note in your logbook what you wore & how much weight you needed, esp if you dive in various conditions (salt vs fresh) and exposure protections. /QUOTE]

This is a good reason to keep a log. I have a page of different weighting for different gear and conditions.

 

[miketsp]

..snip..
My wife--who has a thousand more dives than me -- dives with 24 pounds of lead but is smaller. Go figure.

That would indicate that a densitometer test for Osteoporosis would be recommended.
Bone density reduction will have quite an impact on weighting.

 

[donacheson]

Murph was on the right track, but the explanation needs a bit of elaboration.

First, the diver should be wearing ALL the exposure protection they will using on that dive. This includes hoods, gloves, etc. Add in all the gear.

At the surface with an EMPTY BC, and a FULL lung of air, the diver should be floating at eye level on the surface. When they EXHALE, they should start to sink. If not, more lead is needed.

If the diver will be using a standard AL tank, add 3-4 lbs to compensate for the positive buoyancy of the tank with 1500 psi or less.

Again, it's not an "exact" formula, but more of a "rule of thumb". It WILL take fine tuning to get the right amount of weight to be nicely neutral.

Don't forget to note in your logbook what you wore & how much weight you needed, esp if you dive in various conditions (salt vs fresh) and exposure protections. This will help save time & effort on future dives.

DSDO,

Why use a rule of thumb when the accurate procedure is easier to use? Both require the diver to be in the water with all gear on and the "fine tuning" of which you speak is not necessary if the latter is used.

 

[donacheson]

Weighting really depends on your diving style.

At 215 pounds and a 3mm shorty, I dive with 10 pounds of lead with an AL 80 in salt water. My wife--who has a thousand more dives than me -- dives with 24 pounds of lead but is smaller. Go figure.

Style isn't relevant. The minimum amount of weight needed to complete a dive during which the diver is (or can always be) neutral is a question of physics, not diving style. I can certainly understand why some divers prefer being overweighted, though, an I guess you could say that's a matter of style.

As for your wife needing 24 pounds and your needing only 10, that's no surprise. Weight needed is not proportional to body weight. There are lots of other factors which are important: body density, lung capacity and breathing pattern, tank and exposure suit characteristics, ...

 

[KelpCoasters]

Thanks to all of you that posted suggestions.

According to the DM on our charter, it is suggested that one wear 10% of their weight minus a couple of pounds. This really worked for us.

So - thanks again.

 

[mxracer19]

I beg to differ...style does play a role. Should your trim be slightly aft of your CG forcing your butt down and your head up, or should you tend to swim // instead of == reguardless of weighting, you will require more weight to overcome the lifting force of the water on the underside of your body. this is one way that style can affect weight issues.

-Matt

 

[surfsidedav]

I've meaning to try the following for a way of determining weight. Let me know if its a valid method. Take your suit and fold it down the center line then start rolling it up in a roll from top to bottom. Then tie it so it doesn't unroll. Go to the pool or a deep bucket or whatever and add some weights on a string until it starts to sink. Then you know exactly how much bouyancy your suit adds. Do this with the 7 mil and 3 mil and all else the same, you know how much to take off.

 

[SubMariner]

Why use a rule of thumb when the accurate procedure is easier to use? Both require the diver to be in the water with all gear on and the "fine tuning" of which you speak is not necessary if the latter is used.

Don, with all due respect, there is no magic formula that is 100% accurate because there are many variables, not the least of which is how much air the diver is holding in h/h lungs a the time they do the buoyancy check. New divers tend NOT to completely exhale, which is the reason why as they become more experienced, they require less weight to become neutrally buoyant.

The main thing is that a diver do a buoyancy check & update it periodically so that they can be properly weighted & trimmed.