Lead (diving)

Lead weights are an important part of diving equipment . When diving, you have the task of compensating for the static buoyancy of the diver and his equipment . The amount of lead must be such that the diver can float in the water and tare himself. Depending on the equipment, experience of the diver and the body of water ( salt water has a greater density and therefore more buoyancy than fresh water ), the amount of lead required can be up to twelve kilograms, and in some cases even more. The amount of lead is optimal when the diver with an empty buoyancy compensator and an almost empty pressure bottle can only descend from the surface by exhaling completely. If a diver does not carry enough lead with him, a controlled ascent is not possible, because at the end of the dive the mass of the breathing gas is largely missing. An excessively large amount of lead must be compensated for by the buoyancy compensator, but the buoyancy is strongly dependent on the depth, so that buoyancy is made more difficult by excess lead.

The name lead comes from the material used, the heavy metal lead .

A hard lead weight and two different soft lead cushions as used by divers.

Attachment

The lead weights are usually attached to a weight belt that is worn around the diver's waist. As an alternative to the solid pieces of lead, there is soft lead, which consists of lead granulate and is sewn into fabric bags. There are special belts with pockets for soft lead. Soft lead can be carried more comfortably than the hard and angular solid lead weights.

The weight belt is closed with a buckle that can also be tightened during the dive and that has a quick release device. This means that in an emergency it is possible to open the buckle with one hand movement to throw off the weight belt and carry out an emergency ascent .

As an alternative to the weight belt, there are buoyancy compensators with integrated weight pockets. The advantage is that the diver is no longer constrained by a belt. In addition, this relieves the spine, as the hips are not pulled down and the upper body is pulled up by the suit, as is the case with the weight belt. Additional pockets allow the arrangement and position of the lead to be optimally positioned for the downforce with the help of trim leads. The weight pockets on the buoyancy compensator are also equipped with a quick release device. The disadvantage of integrated weight pockets is that the BC can no longer be safely put down under water. With the vest you would lose the downforce through the weight pockets and would float up uncontrollably. However, in very few cases it is necessary to take off the buoyancy compensator, for example to squeeze through narrow spaces in grottos or wrecks.

In addition to disposable weight pouches and belts, there are also systems without a drop-off option. The lead is z. B. worn firmly screwed together with the bottles on the back. Such systems are particularly used in technical diving where a quick return to the surface, e.g. B. would not be possible anyway or would have fatal consequences due to the decompression obligation.

Weight belt equipped with hard lead weights.

Foot lead

Foot lead is attached to the diver's foot. It is mainly used when divers use dry suits , as the air in the footwell of the dry suit builds up and creates buoyancy there.

Others

Lead is used because of its high density (11.3 g / cm³) and its low price. Based on the world market prices for metals in July 2013, lead has an excellent price-weight ratio. It can also be easily poured into any shape. Lead is the most economical material for making weights.

hazards

The heavy metal lead is poisonous. In particular, the vapors when processing lead are easily and quickly absorbed by the body and can lead to lead poisoning (see also the health hazard when pouring lead ).

When handling lead weights or threading onto the weight belt, it could theoretically lead to abrasion. Smallest amounts of lead could be swallowed if immediately afterwards eaten with uncleaned hands. But there is "not a single case described in the entire medical literature". Overall, divers are “hardly at all endangered with a probability bordering on certainty”. Divers who still want to reduce their personal risk can use lacquered or plastic-coated lead pieces.

Footnotes

1. ↑ To compare the density see also: List of chemical elements .
2. ↑ File: Metallpreise.png - world market prices for metal, June 2013 (lead: sixth inscription from umten)
3. ↑ ^{a b c} Diving Myths. Did you know? In: diving , No. 1/2014, pp. 94-95 (section: medicine ).