How to perfect your buoyancy:
Far too many divers overweight themselves “so they can get down”. Proper buoyancy will make you more comfortable in the water, allow you to consume less air while diving, and avoid damaging our precious reefs. The inverse is also true. If you don’t use proper buoyancy control you’ll feel like you’re going to roll over, blast through that aluminum 80 in 15 or 20 minutes at Gab Gab 2, and screw up our favorite reefs. I’ll show you a couple of ways to nail your buoyancy in this article
Know how much lead you need:
You probably learned in your open water certification class to weight yourself so that you float at eye level holding a full breath (presumably with a full tank). That works fairly well in most parts of the world, but not here in Guam. Why? Well that exercise assumes that you’re wearing a wetsuit of at least 2-3 millimeters like you would in Florida in the spring, or a 5-7mil in California in the summer. The compression of the suit at 15fsw for your safety stop offsets the now almost empty scuba tank on your back. (You will actually consume about 3lbs of air during your dive) We don’t usually dive wetsuits here in Guam, sometimes a dive skin (no buoyancy effect) but that’s about it. If you weight yourself as mentioned above, you’ll always feel a little “light” at the end of the dive.
There are two ways I recommended using to weight you properly. The first way is to use the method above and add 2 to 4 lbs more (2 lbs for smaller people, 4 for us larger folk). If that seems complicated (?) you can also just adjust your weight after a dive (with about 500-700psi in your tank) so that you float eye level holding your breath with a mostly empty tank. I shouldn’t have to get into too much more detail on the process, so let’s talk about what effects your buoyancy.
Tanks will affect the amount of lead you’ll need. A standard aluminum 80 (S80) that is rated to 3000psi will be about 4lbs “lighter” or more buoyant than a compact aluminum 80 (C80) at 3300psi (you can dive with 4lbs less lead). How do you know what tank you have? Just look at the stamped tank marking on the crown of the tank it will say S80, C80, S67, S63, etc. Part of keeping a dive logbook is to use it as a reference. Make notes of what tank you dove, in what wetsuit, how much lead you used, and any other relevant information for later use. It’s only about a pound of difference between the S80, S63, S50, so that won’t change your required weight that much. The C80 is about 4lbs less buoyant so it possible to remove lead from your belt or pockets. The very cool thing about C80’s and steel tanks of all sizes is the ability to remove lead from your “kit” AND the weight of the tank is ideally positioned over your lungs ( where most of your buoyancy comes from). KNOW WHAT TANKS YOU’RE DIVING!!
Control your breathing. As a "new" diver your body usually will not allow you to utilize the full capacity of your lungs. Why? Your body is not used to being underwater and as a stress and survival mechanism it retains about 30% of your lung volume (presumably to keep you from drowning). The cool thing about this "reflex" is that it can be overcome. The more you dive and the more comfortable you are in the water the less your body will feel the need to keep air in your lungs. Work on just relaxing in the water, your body will take care of the rest.
Breath control also controls what portion of your lungs you're breathing from. Huh? I know you learned in you open water dive certification that you should "breath in and out all the way", but that's just a simplified strategy designed to "get you in the water". Proper breath control involves a conscious choice whether to breath from the top of you lungs, the bottom of your lungs, or the center of your lungs, and even the rate of which you breath. I know it sounds complicated, but you'll quickly realize that a little effort will pay off huge dividends on your dives.
I typically utilize about 80% of my lung capacity. If I like where I'm at in the water column I breathe from the center of my lungs. ( when I exhale I retain about 10% of my volume and when I inhale I stop short 10% of the total air I could inhale) If I decide to descend a little I simply breathe off of the bottom 80% of my lungs. ( I fully exhale and stop short on my inhale cycle about 20% of full) If I decide to ascend I simply just breathe from the top of my lungs. (simply stopping short about 20% of my exhale and fully inhaling) USE YOUR LUNGS TO FINE TUNE YOUR BUOYANCY.
Last and certainly least, the inflator button on your BC. The inflate and deflate button should only be used for major buoyancy changes. Obviously when you're ready to begin your dive you should dump most, if not all, of the air in your BC. If you find yourself descending too rapidly add a little air to slow your decent. When you get close to the desired diving depth (within 10-30 feet) begin adding air to your BC to slow your decent. Try to time it so that you become neutrally buoyant at the desired diving depth. Two of the leading causes of reef damage are improper trim and divers "bouncing" off of the reef on their initial decent. REMEMBER THAT YOU BC IS FOR MAJOR BUOYANCY CHANGES ONLY.
Another thing to keep in mind is that different BC's inflate and deflate at different rates. You should own your BC and not rent it if possible. Rental BC's are often used (some would say abused) in training classes. One of the skills you learned in your open water class was to detach the low pressure inflator hose from the power inflator. This skill was included so that in the event that your inflator button sticks or leaks you could safely ascend without a "run away ascent". The problem is that by including this skill in all open water classes is that the rental BC's get salt water or chlorinated water shot through the valve. The valve is similar to the one on your car tire or bicycle tire. As you can imagine the salt and pool water causes extensive corrosion in the tiny valve. That corrosion is usually the cause of leaky or stuck inflator buttons (sometimes causing runaway ascents). BUY YOUR OWN BC!!!!!!!!!
