“Always wear the least weight possible.” If you are a single-tank sport diver, you’re hearing this more and more. So what’s up with that? Okay, you throw on a few more pounds than you actually need. It makes getting down easier and you can always compensate with your BC. No harm done…right?

Wrong. Wearing any more weight than you need is one of the worst things you can do. It:

Makes controlling buoyancy harder

Causes you to use more air

Can adversely impact the environment

Is just plain dangerous

Cave divers know better

It may seem strange to hear a cave diver talking about proper weighting. After all, most cave divers don’t use weight. Why? It’s because our equipment — and especially the large, steel tanks we use here in Florida — is so negative, the weight more than offsets the buoyancy of our wetsuits and drysuits. In fact, it generally leaves us overweighted, without putting on a single kilo or pound of lead.

A cave diver using just a single set of 13-liter/85-cubic-foot tanks can be so overweighted by his gear, it’s like a single-tank sport diver wearing 9 kg/20 lbs he doesn’t need. So why is this a problem?

A properly weighted sport diver will use his BC solely to offset exposure suit compression. This means making the fewest possible buoyancy adjustments.

An overweighted diver, on the other hand, is like a cave diver in heavy equipment. He will not only have to compensate for exposure suit compression, but also the compression of an air bubble in his BC that is there solely to offset the unnecessary weight.

Because most cave divers are overweighted by the equipment they use, they may have to make BC adjustments as frequently as once for every 0.5 m/1.5 ft of descent or ascent. They simply don’t have a choice. Why a single-tank sport diver would do this to himself by wearing too much weight is beyond us.

In general, the difficulties overweighting causes become more pronounced with each unnecessary kilo or pound. However, being even slightly overweighted can cause significant problems. It can even make the difference between life and death. Let’s look at these problems in greater detail.

The yo-yo effect

Many (if not most) newly certified divers say their biggest frustration is buoyancy control. Ideally, no one would get an Open Water Diver card unless they could demonstrate at least rudimentary buoyancy control through proper weighting, breath control and judicious BC use. Unfortunately, too many divers are nowhere close to being able to do this.

This problem has many underlying causes. However, among the biggest is that so many new divers still learn to dive overweighted. And, as a consequence, they dive with the aforementioned unnecessary air bubble in their BCs.

Having to compensate for not only exposure suit compression, but also the compression and expansion of the extra air in their BCs, can lead to what some call The Yo-Yo Effect. This results when even slight changes in depth create such dramatic shifts in overall buoyancy, it is more than a new diver can keep up with.

Due to the weight of their equipment, cave divers can also be subject to the same buoyancy shifts. The difference is, as they are much more experienced divers, they are better prepared to deal with it.

Increased gas consumption

Overweighting can also lead to increased gas consumption. This is for three reasons.

Increased drag: This is partially due to the fact the unnecessary air in the BC creates greater frontal area. (Which would you rather push through the water: an missle or a barn door?) It also results from the fact overweighted divers ten to have poor body position and trim. This, too, results in increased frontal area and drag.

Increased power inflator use: If you are using your BC power inflator more often than you would need to if properly weighted, their is air going in and out of your BC that you don’t get to breathe. This is wasted air.

Greater exertion: Carrying around weight you don’t really need makes you work harder. The harder you work, the more gas you use.

Cave divers can relate to this because they frequently carry large, heavy doubles, stage and deco cylinders, and overinflated BC air cells. And they must do this while pushing against the fire-hydrant-like flow found in many caves. Again, we don’t have a choice. Why any single-tank, open-water diver would subject himself to the same makes no sense to us.

Environmental impact

When divers wear unnecessary weight, it frequently ends up below their bodies’s natural balance point. This is especially true when using weight belts.

Unnecessary weight, worn below a body’s natural balance point, tends to drive feet downward. This leads to poor trim, and thrust from fin kicks being aimed toward the bottom, as opposed to straight back behind the user. It can result in silting, which ruins visibility for everyone and allows silt to settle on coral polyps.

Additionally, when divers’ fins are below them, there is a greater possibility of accidentally kicking coral and other fragile aquatic life. The typical coral stalk grows at a rate of 2.5 cm/1.0 in a year. Break off a piece of coral 25 cm/10 in long, and it will take the reef ten years to repair the damage.

Cave divers are well known for having horizontal trim and body position. This is something every diver should have, as it’s the most environmentally responsible way to dive. But this sort of trim is not something you are likely to achieve if overweighted.

Overweighting’s role in drownings

Panicky divers are notorious for not dropping weight in an emergency. This means that, if these divers fail to inflate their BCs, they may struggle to the point of exhaustion. At this point, properly weighted divers will most likely still be able to remain at the surface. Overweighted divers, on the other hand, will most likely sink and drown. This is true even if they are only slightly overweighted.

You know the expression, “A properly weighted diver will float at eye level.” It’s not entirely accurate; however, the fact remains, properly weighted divers do tend to float — at least a little bit. This greatly increases their odds of survival.

Overweighting is dangerous. It’s just that simple.

Why do divers overweight themselves?

After reading about the potential pitfalls of wearing too much weight, you may be asking, “Why do divers do this?” The answer is, they do it because we teach them to do it during entry-level diver training.

In the all-too-typical Open Water Diver course, students start off overweighted so that they can kneel firmly on the bottom in shallow water. Doing so makes it easier to teach skills such as mask clearing and regulator recovery. But it also get students in the habit of being overweighted. In short order, being overweighted is what feels natural to students. And bad habits, if allowed to form, are much harder to break.

It doesn’t have to be this way. Students can get in the habit of being horizontal and neutral right from the onset. All it takes is a willingness to change how you teach. This article explains how.

Cave diving has contributed much to diving in general. There is no reason why every diver can’t learn to control buoyancy the way cave divers do. Proper weighting is a good place to start.