Overweighted?
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The best thing is for you to do a good weight check.
To answer your question, dropping like a rock when you decend, having to add a lot of air to your BC and having to constantly adjust the amount of air in your BC are good indications of possible overweighting. The type of wetsuit you have on will effect the above indications.
To answer your question, dropping like a rock when you decend, having to add a lot of air to your BC and having to constantly adjust the amount of air in your BC are good indications of possible overweighting. The type of wetsuit you have on will effect the above indications.
The Kraken
He Who Glows in the Dark Waters (ADVISOR)
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You sink like a rock !!!
Just kidding.
There are two requisites to weighting:
1: You must be able to initiate a descent from the surface by deflating your B/C, and exhaling the air from your lungs. You should not have to "swim down" until you become negatively buoyant.
2: You should be able to maintain neutral buoyancy at your safety stop with your B/C deflated, 500 psi or less (shouldn't be less than 500 but sometimes things happen) of air pressure in your tank and breathing normally.
Sometimes if a diver displaces a large amount of water and has a naturally positive buoyancy characteristic and is wearing a large amount of neoprene (ie a 7mm farmer john/jacket) he will probably be "overweighted" at the bottom and at the safety stop. Keep in mind that the neoprene is going to regain its buoyancy when ascending to shallower depth; add to that the fact that you will gain an additional 4 pounds of positive buoyancy.
I imagine you can see the shifting in buoyancy that is taking place here.
It's difficult for me to answer the question specifically about "overweighted during a dive" because of these critical safety factors.
Just kidding.
There are two requisites to weighting:
1: You must be able to initiate a descent from the surface by deflating your B/C, and exhaling the air from your lungs. You should not have to "swim down" until you become negatively buoyant.
2: You should be able to maintain neutral buoyancy at your safety stop with your B/C deflated, 500 psi or less (shouldn't be less than 500 but sometimes things happen) of air pressure in your tank and breathing normally.
Sometimes if a diver displaces a large amount of water and has a naturally positive buoyancy characteristic and is wearing a large amount of neoprene (ie a 7mm farmer john/jacket) he will probably be "overweighted" at the bottom and at the safety stop. Keep in mind that the neoprene is going to regain its buoyancy when ascending to shallower depth; add to that the fact that you will gain an additional 4 pounds of positive buoyancy.
I imagine you can see the shifting in buoyancy that is taking place here.
It's difficult for me to answer the question specifically about "overweighted during a dive" because of these critical safety factors.
cmalinowski
Contributor
Sinking like a rock 
Seriously, I am not an expert, but if you need to have lots of air in your BC to stay off of the bottom, then you are probably overweighted. The test is that whole "empty BC, full breath of air, be at eye level on surface--When you let out the breath you should sink" think.
The main thing is to be just slightly negative with empty BC at safety stop with 500 lbs.
Seriously, I am not an expert, but if you need to have lots of air in your BC to stay off of the bottom, then you are probably overweighted. The test is that whole "empty BC, full breath of air, be at eye level on surface--When you let out the breath you should sink" think.
The main thing is to be just slightly negative with empty BC at safety stop with 500 lbs.
mm777:
During a dive? If you can't get off the bottom that would be a sure sign.
The best time to tell is at the end of a dive. With a near empty (+-500PSI) you should be able to able to bob at eye level with average lung volume while bewnig still, no finning or sculling.
Pre-dive you can use the same exercise but you need to add on for the weight of the air you will consume. Probably 5-6 pounds. Based on your cylinder size use you can calculate this using .08 cf per pound. You can confirm the set-up at the end of the dive. Also make sure all of the air is out of your gear. BC material can take a few minutes to wet out.
The balance point is to be barely positive at the END of your dive, this will allow you to stay down at your safety stop.
Remember that if you go from fresh water (like a dive shop pool) to salt water you will need to add another 2.6% of total diver weight to accound for the greater bouyancy you will experince in the denser ocean water. Reverse the calculation when going from the ocean to fresh. Diver, cylinder, weights gear etc.... example = 250 pounds X .026 = 6.5 pounds extra.for the ocean.
This can get you quite close, my wife and I were right on fllowing the above. I'm sure we can drop some with experience. These calculations can get you close enough but the end of dive check is the confirmation.
There are other methods but this one seems to be the most common.
Pete
One thing you can try is to look behind you.
Does it look like a sandstorm in your wake?
If so, this is a clue that you're overweighted!
(You are consequently moving through the water at a 45 degree angle, head up feet down, pushing more water than you need to, with your BC holding more air than it needs to, expending more effort and energy than you need to, and aimimg the blasts from your flutter kicks directly at the bottom. This is called rototilling, and it annoys the daylights out of other divers!)
Fortunately, proper weighting is not that difficult, and it will improve your diving immensely and allow you to expend less energy, so you'll have more fun!
Good on you for focusing on proper weighting, it will pay dividends in your future.
Doc
Does it look like a sandstorm in your wake?
If so, this is a clue that you're overweighted!
(You are consequently moving through the water at a 45 degree angle, head up feet down, pushing more water than you need to, with your BC holding more air than it needs to, expending more effort and energy than you need to, and aimimg the blasts from your flutter kicks directly at the bottom. This is called rototilling, and it annoys the daylights out of other divers!)
Fortunately, proper weighting is not that difficult, and it will improve your diving immensely and allow you to expend less energy, so you'll have more fun!
Good on you for focusing on proper weighting, it will pay dividends in your future.
Doc
mossym
Contributor
Doc Intrepid:
this is a big one..and because you may not actualy hit the bottom and do this, you might never know...get someone to take a video of you if you know someone with a camera..it's a real eye opener, or at least was for me..
o calculate your BMI you need to do the following calculation:
* Divide your weight in pounds by your height in inches squared.
* Multiply the result of step 1 by 705
So if you are 5ft 3in (63in) tall and weigh 10 stone (140lb), the BMI equation goes like this:
# BMI = 140 divided by 63 x 63, multiplied by 705 = 24.9
If your BMI is:
* Under 25, you are lower than average and can breathe a sigh of relief.
* 26 - 30, you are over classified as "overweight" and need to shift some.
* 31-plus, you are obese and definitely need to shift some.
here is an exception to this rule, however. Some men, particularly, can be lean but carrying a lot of heavy muscle. If you are one of these, do the calculation and come out as having a high BMI, use your common sense. Go back to the mirror. If your belly is not hanging over your trousers, then don't panic.
At the moment it is left to the discretion of the diving physician to certify people fit to dive when a BMI is showing you to be overweight or obese.
While you may get the official OK, it is clearly going to reduce your risk of injury while diving if you are within the normal ranges.
Percentage body fat
If you have a flashy set of bathroom scales that tell you not only your weight, but also your percentage body fat, you can also use this measurement to give a sense of perspective to weight issues.
Remember that women naturally have a higher percentage of body fat than men. A sedentary woman usually has around 25% body fat, while trained women can dip to 15%.
It is desirable for women to have less than 28% body fat for diving.
Trained men can go as low as 7-10% body fat, but less than 22% is the desirable level.
I hope that this helps you!
* Divide your weight in pounds by your height in inches squared.
* Multiply the result of step 1 by 705
So if you are 5ft 3in (63in) tall and weigh 10 stone (140lb), the BMI equation goes like this:
# BMI = 140 divided by 63 x 63, multiplied by 705 = 24.9
If your BMI is:
* Under 25, you are lower than average and can breathe a sigh of relief.
* 26 - 30, you are over classified as "overweight" and need to shift some.
* 31-plus, you are obese and definitely need to shift some.
here is an exception to this rule, however. Some men, particularly, can be lean but carrying a lot of heavy muscle. If you are one of these, do the calculation and come out as having a high BMI, use your common sense. Go back to the mirror. If your belly is not hanging over your trousers, then don't panic.
At the moment it is left to the discretion of the diving physician to certify people fit to dive when a BMI is showing you to be overweight or obese.
While you may get the official OK, it is clearly going to reduce your risk of injury while diving if you are within the normal ranges.
Percentage body fat
If you have a flashy set of bathroom scales that tell you not only your weight, but also your percentage body fat, you can also use this measurement to give a sense of perspective to weight issues.
Remember that women naturally have a higher percentage of body fat than men. A sedentary woman usually has around 25% body fat, while trained women can dip to 15%.
It is desirable for women to have less than 28% body fat for diving.
Trained men can go as low as 7-10% body fat, but less than 22% is the desirable level.
I hope that this helps you!
The Kraken
He Who Glows in the Dark Waters (ADVISOR)
ScubaBoard Supporter
Scuba Instructor
Divemaster
Filauri,
The thread in question is about whether or not a diver is "overweighted during a dive", not whether a diver is overweight.
"Overweighted during a dive" is referring to the amount of lead weight the diver is carrying to obtain proper buoyancy control.
The thread in question is about whether or not a diver is "overweighted during a dive", not whether a diver is overweight.
"Overweighted during a dive" is referring to the amount of lead weight the diver is carrying to obtain proper buoyancy control.
Charlie99
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That's not a very definitive check. A diver wearing a lot of neoprene, and/or carrying a lot of gas in a large capacity tank will have to add lots of air to their BCD at depth. Even if they are properly weighted.cmalinowski:
You really have to look at the amount of air in the BCD near the end of a dive, while 15' or less in depth, and without much air in the tank. Needing air in the BCD in this condition is an indication of being overweighted.
To check weighting properly you need to master the skill of doing nothing. Keeping arms and legs/fins perfectly still can be hard, but you can't really figure out weighting and trim until you really can keep motionless.
The other thing that divers have to pay attention to is at what point in their breath cycle that they are truly neutral. From full forced exhale to full forced inhale (vital capacity) is typically about 5 liters --- or a buoyancy change of about 10 pounds! Even normal, unforced breathing can easily be 5 pounds difference in buoyancy.
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