Scuba Diving performing a buoyancy weight check

Scuba Skills: Performing a Weight Check on the Surface.

Diving incorrectly weighted will increase your air consumption and hold you back from attaining that amazing weightless feeling that we’re all chasing. If you’re weighted incorrectly you will either spend the whole dive adjusting your BCD, or battling to prevent yourself from floating up on your safety stop – neither of these is fun or safe. By performing a weight check on the surface, you will get a better understanding of how much weight you really need and have better dives because of it.

Performing a buoyancy/weight check:
  1. Enter the water (fully geared up) with your BCD fully inflated. (You can do this just off the back of a boat or out in a bay where you aren’t touching the bottom. Remember if you do this in a pool your results will be slightly different because of how salt water can also affect buoyancy.)
  2. Once you are comfortable, breathe in and hold a normal breath.
  3. While you hold your breath, slowly let all of the air out of your BCD.
  4. If you are correctly weighted, you should float at eye level with the water. Meaning that you will have sunk enough to have water running across the middle of your mask.

If you start to sink, kick up and fully inflate your BCD. Once you are comfortably floating again, remove 1 weight from your configuration. Hand the weight to your dive buddy and attempt steps 1 – 4 again.

Keep repeat the process until you comfortably float at eye level – Now you should be perfectly weighted!

If you find that you are floating instead with your head above the water do the same thing in the other direction. Add one weight to your configuration and repeat steps 1 – 4 until you comfortably float at eye level.

 

Common mistakes:
  1. Kicking up or using your fins as you let the air out of your BCD. This is going to give you the impression that you are either floating at eye level or that you are not sinking. Make sure you relax in the water and let your feet hang beneath you.
  2. Taking a giant breath in. This is also going to give you a false reading, you only need to hold a normal breath.
  3. Breathing out while you let the air out of your BCD. Try putting your hand on the back of your regulator to remind yourself not to breathe out.
  4. Forgetting to kick up once your head is below the surface. As soon as you see that you are sinking quickly, kick up and inflate your BCD so that you can adjust your weights and try again.

 

Things to remember:

As you use the air in your cylinder, you will become lighter. If you perform your weight check at the start of a dive with a full cylinder, you might need to add a weight back on. This is so that you can comfortably complete a safety stop at the end of your dive when the cylinder is emptier.

Consider is which type of tank you are using. Aluminium cylinders are much more buoyant (they float) than steel cylinders (they sink). So if you change which cylinder you are diving with, you may also want to adjust your weights.

Think about what kind of exposure suit you’re wearing. A drysuit will require a lot more weight than a bikini. If you have changed what you’re wearing then you may also need to adjust the amount of weight you’re carrying.

 

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