One of the biggest, yet, most common mistake a diver can make is being overweighted. Making sure you are properly weighted for your dive is not only safe but makes diving easier and more comfortable. Having to struggle to stay on the bottom because you are underweighted can make your dive frustrating and, let's face it, no fun. However, being overweighted significantly increases your risk of injury in the unlikely event an emergency arise, and it also affects your air consumption by trying to fine-tune your buoyancy underwater.
When and why should I do a buoyancy check??
A properly executed buoyancy check will allow you to determine if you are wearing the correct amount of weight before you descend for your dive. If you are over or underweighted, you will be able to add or remove weight before you descend. It is a good idea to start ever dive when using new gear, a different thickness of wetsuit (or drysuit), different dive location (i.e. different ocean, lake, etc.) and/or different cylinder type/size. If you are new to diving, the buoyancy check skill was taught to you in your open water course during one of your pool sessions. This is a good base point to determine how much weight you will need in the ocean.
How to properly execute a buoyancy check
- Step 1: In the full gear you will be wearing on your dive, deflate your entire BCD.
- Step 2: Take a full breath in to fill your lungs with air and then HOLD IT!
- Step 3: Calmly scull your arms while keeping your legs still (do not kick!) to stay above water and...
- Step 4: Slowly stop sculling, and SLOWLY lower your arms to your side. You DO NOT want to be bobbing at this point!
- Step 5: You should be floating with the surface of the water at eye level. If you just sink or float a bit underwater you are overweighted, and if you float with your eyes, nose or chin above the water you are underweighed.
- Step 6: FORCEFULLY blow out the breath you have been holding...you should then sink underwater. (if this does not occur you are grossly underweight).
- Step 7: Adjust your weight accordingly and then try the buoyancy check again until you float at eye level.
Guidelines for adjusting your weight when diving different gear or waters
Once you know the base amount of weight you need for your usual diving, there are general rules of thumb on how to add/subtract weight when changing your gear or diving location.
- Going from Freshwater to Saltwater Diving: add around 5-6 lbs to your weight belt; taking off the same amount when going from Saltwater to Freshwater.
- Going from a thinner to thicker wetsuit (or even just adding boots, gloves and hood): Any time you add neoprene you become more buoyant. Add weight in 2 lb. increments until you pass your buoyancy check. Take off weight the same way when decreasing to a thinner wetsuit.
- Going from an Aluminum 80 tank to a steel tank: take off roughly 6 lbs. and vice versa when going from steel to aluminum.
Keep in mind that this is a rough, generalized guide to adjusting your weight. It will not be the same for everyone, so make sure you check your buoyancy often.
A final word on your weight:
Most divers end up overweighted due to the sheer fact that they feel like they cannot get themselves underwater to begin their dive. You may not have thought of it this way, as it is just a matter of getting underwater, but the initial descent is a skill unto itself. You need to start your dive off in a relaxed manner. The key to this is: empty your BCD and EXHALE to get underwater! Our bodies are so used to taking a deep breath before submerging ourselves, but doing so will never allow you to descend. So, on your next dive try a buoyancy check, relax and exhale to descend. Soon you will be diving better weighted then you ever have before!
