How to freedive in Variable Weight

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You prepare on the surface, controlling your breathing to relax to the fullest. Your buddies are ready to support you, the weight/sled is ready to drop. You take a deep breath, filling your lungs to full capacity. As you remove your snorkel from your mouth (this is the signal), your partner opens the pulley to drop the weight/line from which you hold on, and thus begins an exciting journey to the depths.

You let yourself be pulled, graving the line, diving deeper and faster, almost effortlessly.

This thrilling experience requires relaxation and good equalization control.

You can stop the descent whenever you want (or release the weight and continue freefalling), then ascend (without ballast) feeling very light. Achieving positive buoyancy already at 20m or deeper, and from there, effortlessly ascend to the surface, taking advantage of the high buoyancy, breaking the water's surface to breathe calmly, with plenty of energy. Easy dive!”

This is a basic, general idea of variable weight apnea. Sounds fun, right? It certainly is, but it requires technique, teamwork, and good logistics.

This discipline is not for beginners, as it requires a good mastery of equalization, proper logistics, and high-level supervision/support.

My Experience

I started including variable weight in some of my training sessions during the second year of practicing apnea. I did it in a very self-taught and rudimentary way. Back then (1999), we had no technical knowledge, safety measures, or good logistics. We did everything purely out of passion and curiosity.

Including VWT dives in my training schedule help to improve my equalization control, and to explore new depths before trying it in CWT or FIM.

Over the years, as I improved my technique, experience, and logistics, I achieved two VWT world records in 2004 (135m) and 2006 (140m).

In this article, I will give you some recommendations so that you can make the most of this interesting training and recreational tool while avoiding unnecessary risks.

Getting started

There are several ways to practice Variable Weight, depending on your goals and logistical resources. In this article, I will provide a basic classification for amateur, non-professional freedivers. However, I’ll describe some fundamentals of sled diving too.

Variable Weight Head first Pendulum

In my opinion and experience, this is the simplest and safer way to practice for amateur level

This can be done using the buoy-pulley-line-weight system of a freediving training buoy. Of course, lanyard is a must.

When the freediver is ready to dive, the buoy line is dropped opening the pulley to control the descent (a safety buddy should take care of line/pulley control). The diver holds onto the line and allows himself to be pulled, always ready to release the line if he experiences equalization problems, or if prefers to continue freefalling until the end of the line (lanyard stopper).

It is essential to have good safety support: a safety diver and an assistant to control the line and prevent entanglements (both should be experienced freedivers, at master level).

Freediver and safety must agree in advance on a maximum depth for the drop line, then make a knot in the line to stop it at the agreed depth. A second safety knot should be attached to the buoy.

The freediver dives without weight belt, without neck weight. All the weight is in the line (bottom weight). The bottom weight should not be heavier than 15Kg and the buoy must be in very good condition.

Variable Weight with Head-down Sled

It is necessary to develop a weight/sled that descends guided by a vertical line. The diver holds onto the sled and releases it from the buoy to dive down.

The line remains fixed until the planned depth; it is the weight/sled that moves, taking the diver toward the bottom. This weight/sled must glide guided by the line using carabiniers or a tube (like a classic sled).

The diver must be ready to release the weight at any time they feel discomfort in equalizing or if they decide to continue the descent in freefall. Then the sled will glide till the end of the line to the lanyard stopper.

One technical and safety disadvantage is the risk of entanglement between the lanyard and the weight/sled. This can be avoided with a well-designed sled.

Variable Weight with Feet-first Sled

This is the most professional way to practice Variable Weight Diving. The sled must have a breaking system to control the descent speed or simply stop the descent at the diver's discretion.

It requires heavier logistics, like a platform/arm or boat with arm. Also, the safety team should be bigger and professional.

Counterballast system could be very dangerous, since the lines can cross in the depth. My advice is to use an electrical winch system for safety and logistics.

Risks

Lack of control in equalization during the descent is a critical risk to consider: the diver must be able to stop or slow down their descent at all times, either by releasing the line, releasing the weight/sled, or activating the sled's brake.

It is crucial to be aware of the depth and characteristics of the seafloor in the practice area, as the risk of hitting the bottom must be avoided at all costs. I always recommend practicing in an area with an extra 10 meters of depth or more. Also, leave ample space between the lanyard stopper and the bottom weight.

Another risk to avoid is scuba divers around the area. Practice VWT far from scuba divers. A bottom weight falling over a scuba diver can be catastrophic.

Avoid training Variable Weight Diving with other parallel lines close to the sled's descent zone or the variable weight line. There is a high possibility of line crossing at depth since the trajectory during VWT descent is not perfectly vertical; there is always a diagonal displacement of the diver, which implies a very dangerous entanglement risk. My advice is to have only the variable weight line within a 15-meter radius.

Even the counterweight line (if you are using one) poses a high risk.

Before practicing Variable Weight Diving, I recommend getting certified as a Master Freediver, both for yourself and at least one of your training partners.

My final recommendation is that if you want to include VWT in your practices, you should have two well-trained partners to support you, and you should gradually progress to learn how to control all the risks and logistics I have mentioned.