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Weights
The human body has a density close to that of water, and most people find that the amount of air in their lungs is sufficient to move them from slightly positively buoyant in fresh water with full lungs to slightly negative with maximum exhalation. Sea water is about 3% denser than fresh water, and thus a person that is approximately neutrally buoyant in freshwater will be a few pounds buoyant in sea water (roughly 3% of body weight). A diver also carries a significant amount of gear along. Much of it may be approximately neutrally buoyant in the water, the notable exception being the diver’s thermal protection (wetsuit or drysuit). The air trapped by the suit near the surface of the body may make great insulation, but it also adds buoyancy—typically 10–35 lbs. for cold-water wetsuits (depending on the thickness and design) and drysuits. Divers carry extra weight in order to maintain neutral buoyancy so that they can stay at any depth without effort. There are several important considerations in choosing how much and what type of weight to carry. Safety is the first consideration. Don’t carry more weight than you need, and make sure that you can release at least 80% of it quickly and easily to establish positive buoyancy in an emergency. After that, you should consider comfort, trim and ease of use. How Much weight? How much weight you need depends on both you and gear-of-the-day (and whether you’re diving in fresh or salt water). The only reliable way to adjust your weighting is by testing in the water with your gear. A good rule of thumb is to adjust your weight so that with a full tank and full lungs, you float with your eyes approximately even with the surface of the water. As you exhale, you should slowly sink, and if you take a breath, you should slowly rise. The goal is to be neutrally buoyant at the end of your dive with a nearly empty tank for your safety stop at 15 feet. Two factors will change your buoyancy over the course of a dive. Your wetsuit will compress with depth, and you will need to add air to your BC to compensate. An typical 80 cu ft typical tank holds about 6.5 pounds of air, and you will gain about 5.5 lbs. of buoyancy by the time your tank is down to 500 psi at the end of a dive. Beginning divers often have trouble learning to let all the air out of their BC during the course of the dive. Divers tend to compensate by carrying too much weight. The best solution is to understand that air in your BC is always going to float to the highest point and to utilize the appropriate dump valves according to your orientation in the water. Carrying more weight than you need defeats the feeling of freedom underwater. Having too much weight around the waist pushes your lower torso and legs down and compensating with the BC raises the chest up. This creates huge unecessary drag in the water and eliminates the feeling of gliding weightlessly through the water. Students in basic SCUBA classes are ofen overweighted and need to learn to dive with proper weight. If you have a wetsuit on, and you are able to sink by deflating your BC at the surface, you may have too much weight. Being properly weighted will require a diver to do a surface dive or pull themselves down a line in order to get underwater. But it is important also to have enough weight to be neutrally buoyant for a safety stop at the end of a dive. How to mount? The traditional weight belt with, say, a 10 lb. weight mounted on each hip is not the most comfortable diving accessory. You can improve comfort by stringing more smaller weights such as bullet weights along the belt. We also offer “soft” weights, which are pouches filled with lead shot that conform to the body without sharp edges. Increasingly, divers are discovering that it is easier and more comfortable to carry at least some of their weight somewhere other than a belt. If you have a weight-integrated BC with quick release weight pockets (do not use zipper pockets for weights!), you may find that your diving is easier and more comfortable with all or some of your weight in your BC. The downside of having all of your weight in your BC is that the BC plus tank, regulator and weights may be too heavy to comfortably lift. The alternative is to divide the weight between the BC and a weightbelt, putting a maximum of about 10 lbs. in the BC and the rest on a belt that can be lifted and mounted separately. If you do not have a weight-integrated BC, you can add similar weight-mounting possibilities using a separate DUI Weight and Trim System harness. Of the basic types of conventional weightbelts, we recommend either nylon or rubber. The advantage of nylon is that it is inexpensive, easily adjustable, and has a long life. Rubber belts, on the other hand, stretch around the diver and compensate for wetsuit shrinkage as the diver descends in the water column. The stainless steel wire buckle systems we sell for rubber weight belts tend to be much more secure and are suitable for overhead environments such as caves and wrecks. What about Trim? The other reason to distribute weight is to control “trim” in the water. If you find yourself working to hold your desired orientation in the water, you may need to move a few pounds of weight around to adjust trim. We offer ankle weights and tank weights which can be used for this purpose, and you may also want to attach some weight to your shoulder straps. Usually a pound or two in the right places is all you need. We recommend minimizing any weight on your ankles, because it makes it harder to swim and walk. Freediving  Outstanding freediving weight systems are now available. Free diving buoyancy comes mostly from large
lungfuls of air the diver takes in before descending. A free diving weight system places the lead ballast
directly over the diver’s lungs. This system also greatly reduces back fatigue compared to a
traditional weight belt. This system cannot be used for SCUBA diving, however, because the weight cannot be easily
ditched in an emergency with a BC on.
Disclaimer: The information provided here is intended solely to help in product selection for trained and certified divers and is in no way intended to substitute for formal training and certification. |
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Ankle Weights
Nylon Weight Belt
Rubber Weight Belt
Weight Belt Buckle
Plastic Slide
Serrated Bar Slide
Bullet Weights
Soft Weights
Tank Weights
Seasoft Weightbelt
Bulk Nylon Webbing
Plain 2" Bar Slide