proper weighting

[MNScuba]

I'm not disagreeing with you devilfish, and in some cases I'm sure you are correct. Keep in mind that my post was not about warm saltwater diving as I clearly indicated. I'm just trying to help kwaite find a starting point. This is the formula I've used and it works ok for me, if you have one you like to use or feel is better, why don't you post it? The truth is that 3 students out of 6 were supposedly 'underweighted' in my class... keep in mind they had 7 mil wetsuits on with hood, thick gloves and thick boots. The real fact is that most people ARE probably overweighted and do not have enough buoyancy control to use the proper weight. After time and after some practice I'm sure I'll shed a lot of the weight that I think I need right now. According to PADI, I'm not incorrect on my suggestion.

Take a look for yourself:
http://www.padi.com/fun/reading/readinggen.asp#q2

 

[devilfish]

With all due respect MNScuba, I know what PADI peak performance said. Keep in mind that much of the material in educational manuals, all agencies are written by nondivers or those that seldom or never dive anymore. I read in an educational manual, don't want to mention names, that at two ata's there is half amount of gas in the tank. Some bright writer took some information not understanding diving physics and assumed that because a diver would have half the time, etc... And most magazines, I want to scream when I read some of the BS. What a joke.
But you are right, there are no formulas, each individual is different for proper amount of air.
The key is properly performed buoyancy check. Vertical, no kicking, no flopping, empty bc.

 

[MNScuba]

But you are right, there are no formulas, each individual is different for proper amount of air.
The key is properly performed buoyancy check. Vertical, no kicking, no flopping, empty bc.

I can't WAIT until I find my ultimate buoyancy! I had it once, then lost it when I inhaled, lol.

Quick note:
Thank you for challenging my opinion, I'm a rookie and therefore shouldn't be arguing matters such as this one and probably many others that I've stuck my nose into. I do enjoy giving my opinion from time to time... unfortunately at this stage in my game, my opinions are mostly based on reading, questions I ask and what I hear. I will challange responses that don't have a valid reasoning however. I can clearly understand where you are coming from and there really is no easy shortcut to proper weighting other than getting in the water and using the 'trial and error' technique (adding weight as needed). It is much better to jump in the water and be underweighted than overweighted, you are correct on that as well.

 

[devilfish]

Ahh, but would you believe that a time may come when you can inhale and exhale normaly without going up and down, yes while underwater.

 

[Jarhead]

that you should take lessons from the former "President" about not inhaling, but I can't bring myself to mention that name.

Jarhead

 

[Cheaper]

Hi
As a rule of thumb add 1 kilo of lead for every stone of body weight so if you weigh 140lbs then you should have 14 kilos of lead on your belt for sea water,in this stage of your diving it is beter to be slighly over weighted on say the first dive and drop weight on the second and third.

Kevin

 

[devilfish]

You can't be serious. Almost 31 lb or 14 kg on a 140lb diver, that's outright dangerous.

 

[The Chairman]

Start with a full tank... no weight... in whatever water you want to figure out your weight. Empty your BC completely (suck out what is left) and with everything on (including your exposure suit) jump in. Take a moderate to full breath and hold. Have someone measure the distance from the top of your head to the water. For each inch, add a pound. For those who stick WAY out, you might need to add some weight so you are within the 1-10 inch mark and measure how much additional weight your need. WHEN you add the weight you calculated, the top of your head should just break the surface. Yes, this should weight you properly for when your tank is down to 500 psi and you are at your safety stop. Try it, it works!!!

 

[Cheaper]

Hi
My last post should have said a 140lb dive who who is 10 stone should have 10 kilos of lead not 14kilos although the formula was correct.

Kevin

 

[pt40fathoms]

Stone? how about measuring depth in cubits.

Sorry, just couldn't resist. I haven't heard stones used for measurment of weight,,,ever. Except of course in British comedy.

But seriously now, NetDoc's system seems not bad, however, trial and error, experimentation, and keeping a a good log are the only ways you will establish what "your" bouyancy will be in any given situation. Take me for example:

Mares 7mm wetsuit with hooded overshorty, AL80, Fresh water = 32 Lbs.

Bare 7mm Farmer John with hooded jacket, AL80, Fresh water = 36Lbs.

Mares 5/4/3 with hoodd overshorty, AL80, Fresh water = 26 Lbs.

Mares 5/4/3 with hood, AL80 Fresh water = 20 Lbs.

Shorty wetsuit no hood AL 80, Fresh Water = 10 Lbs.

All the above with my Steel doubles subtract 10 Lbs.

All the above in salt water add 6 Lbs.

And so on... Every time I change add or remove gear, my bouyancy will change. Sometimes just a little, and sometimes alot.

So the only right answer, is no answer, other than a guess at what you should start at. The rest is up to you. When you find a combination that works well, always remember to document it.
The only advice as to a starting point that has already been made on this thread that I would follow is, being a **little** heavy is far more desirable than being a little light!