Oppdrift i vann - hvor mye bly skal jeg bruke når jeg fridykker?

Buoyancy in water - how much lead should I use when freediving?

Photo: Aleksander Nordahl, ettpust.com

Buoyancy in water

When you freedive, you usually wear a freediving suit. These suits float very well, and that is essentially why we need lead when we free dive. Without lead, you simply cannot get down.

If you snorkel or freedive with a wetsuit with a zipper in 5-7mm neoprene, you will have the same need for lead if you want to dive.

How much lead should I use?

It depends on how thick and how big the suit is, as well as how your own buoyancy is in the water. For those of you who do not have a relationship with this, this may sound difficult to calculate. It is not.

A first clue as to whether you have the right amount of lead can be obtained by standing in an upright position in free bodies of water while holding your breath with your lungs full of air. The whole head should then be above water, but the shoulders should be under water. This is an indication that you have positive buoyancy (you float) down to a depth of about five metres. At a depth of six meters you become neutral, and from 7 meters downwards you get negative buoyancy (you sink). See the guide at the bottom of this page.

More or less lead on different types of freediving?

The example above is the normal adjustment for recreational freediving and underwater hunting. This is fine for those who dive to depths between 5 and 20 metres. If you regularly dive to a depth of 15 meters or more, you may benefit from wearing less lead. This means that you have to dive a little further down before you become neutral in the water, but you also become less negative at greater depths. It is not good to become very negative on deep dives. Then you use a lot of effort to get back up to the surface.

If you exclusively dive in shallow water, for example for underwater photography at a depth of 1-5 metres, you can use more lead so that you can lie calmly on the bottom without floating back up. But be aware that you should always have positive buoyancy at the surface.

Recommended equipment and benefits with vest and ankle weights
Always use a rubber lead belt. It should tighten around the hip like a rubber band, and continue to tighten as you compress in depth. Steer clear of nylon belts (not elastic).

In the belt, you preferably use rounded lead weights , the most common being 2kg weights. If you want the best solution, rubberized weights are the choice. They are glued to the belt and do not move during use.

One should always put the main amount of the lead in the lead belt so that a belt drop is enough to ensure a quick ascent. It is still a great advantage to use a lead vest and ankle weights in combination with the lead belt. Not only do you get a more comfortable distribution of the lead, you freedive and much more efficiently. Even swimming is easier with ankle weights on your legs.

Lead vest
With a lead vest, the dive becomes easier, and you can relax on the seabed.

A simple guide

If you use a 7mm freediving suit, this is a guide to how much lead you should use for recreational freediving from 0-15 meters deep.

Suit size, Indicative amount of lead

Size 2 or Small 6 - 8 kg lead
Size 3 or Medium 8 - 10 kg lead
Size 4 or Large 9-12 kg lead
Size 5 or X-Large 12 - 14kg lead
Size 6 or XX-Large 13 - 15 kg lead

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