How many kilograms of weight do you bring underwater with you? I don’t talk about your weight but the extras you carry on the weightbelt or in the pockets. Do you change the amount depending on where you dive? Do you struggle with buoyancy and holding your position in the water?
Not only new divers carry way too much weight around. Often during courses people get a bit extra so they can stay down easier. I am no friend of that practice but that’s not to discuss here.
It is of central importance to bring the correct amount as this makes the diving experience much more enjoyable. It can even be dangerous to bring too much.
It would clearly be best to get it right from the beginning.
The amount of weight you need during a dive depends on many factors. First of all you need weight to bring your body down, this amount varies between male and female, size and so on.
In addition it changes between fresh and salt water, even in the ocean it varies between different areas. The thickness of the wetsuit, type of tank (steel or aluminium) and the size of the tank influence the number of weight you need to bring.
It’s easier when I carry a bit more
I often hear that divers prefer to bring extra weight as it makes it easier to get down from the surface. This is only such a small part of the dive. For the rest of it this attitude will make it harder.
Others bring too much to have more stability when taking photos underwater. This would only work when you actually put yourself down on the ocean floor. As this is not how it should be done and will destroy whatever is underneath, don’t do it!
So usually there is no need to bring extra weight.
Just a little bit too much won’t matter?
That’s what I thought until recently. I went diving with 3 kg extra and with more than half of the weights unevenly distributed on a weight belt. I am not used to wearing such a belt and I was diving in a thicker wetsuit than normal (requiring more weights anyway).
My buoyancy was completely off. We were in blue water looking at sharks. I had to check my computer every few seconds to make sure I stayed at the right depth, I couldn’t even keep a horizontal position without kicking.
Not very nice, isn’t it?
It does matter
The main reasons why it does matter are
- extra weights need extra air
- overweight makes it harder to get neutrally buoyant
- overweight makes it harder to get your trim right
So why is that? The additional weight needs to be balanced with extra air in the BCD. This air contracts and expands with depth changes requiring you to add or release air more often during the dive.
Each time it might be a bit too much or too little air added causing the buoyancy to be off. This can lead to a constant fiddling with the LPI (low pressure inflator) preventing you from actually mastering the buoyancy.
Good buoyancy control also means using the BCD as little as possible. The main buoyancy control device should be your lungs.
Bad for the environment
Another really important reason why it matters is the environment. Overweight divers are under a much higher risk of damaging coral or other organisms. It takes longer to become neutrally buoyant and this should be established long before reaching the ocean floor.
When fiddling around with the LPI a diver might accidentally get too close to coral.
The trim is often not ideal when overweight. This might cause the legs to go down when the diver stops swimming. This position, fins down, is dangerous as they often then touch the ground or are so close above that sand or silt is stirred up.
It can be dangerous
In case of an emergency like a leak in the BCD or a distressed diver at the surface the additional weights can be dangerous. When the diver forgets to ditch the weights the risk of sinking down from the surface is increased.
A properly weighted diver doesn’t sink like a rock from the surface even with a deflated BCD.
How to know the right amount of weight
To make sure you have the right amount of weights observe how you feel at the surface. If you almost sink with an inflated BCD you are definitely carrying too much weight. Remove some and see if you can still descend.
The right amount of weight is as little as possible! The least amount of weights where you can still stay down during the dive is the correct amount.
The best way to find out if you are carrying too much weight is during the safety stop.
- at 5m with only 50 bar or so left in the tank
- release all air from the BCD
- if you have to kick up to stay at 5m you have too much weight
- remove one weight before the next dive
- try again and repeat if necessary
Positioning of the weights
To get a feeling if your weights are correctly positioned on your weight belt try the following
- become neutrally buoyant in a horizontal position
- stop moving
- observe what your body does
If your legs sink down move some weight from your weight belt or pockets to somewhere higher like trim pockets or the tank strap. Alternatively move the weights on your weight belt more to the front
If your legs go up move the weights on the belt more towards your back (make sure the weights are not below your tank)
If your body turns to a side try to evenly distribute the weights on the belt.
Do the adjustments after the dive on the boat or on land. Never take the weight belt off underwater!
But I need the weight to get down
Most times when someone struggles to get down there is either air in the lungs or in the BCD. This will help:
- try to relax before you start to descend
- take your time (if the conditions allow) to take some deep breaths through your regulator on the surface
- when you feel ready, breathe out very deeply, release the air from the BCD and you should go down
If there is still some air left in the BCD
- move around a little
- make sure that you are completely upright
- lift your left shoulder a bit higher (so the valve is the highest point of the BCD)
- make small moves forwards and backwards to release any trapped air
Too light in the end
If you feel too light at the safety stop make sure that all the air is out of the BCD (that’s how it is supposed to be).
Remember to be upright when releasing the air from the hose or alternatively use the dump valve.
If this doesn’t help and you still feel too light make sure you breathe slowly and fully breathe out.
If this still doesn’t do the trick you probably do need the extra weight. Add one weight and you will be fine during the next safety stop.
Carrying the right amount of weight evenly distributed will make buoyancy control and trim much easier.
This and less air being pumped into the BCD will allow you to stay down longer and be more relaxed.