Constant Weight Freediving – Everything To Know

An overview of how to constant weight freedive, the inherent risks, and the equipment needed to do it.

Freediving isn’t always done recreationally. There is a competitive sport aspect to it that many people are unaware of. In this article, we discuss everything you need to know about this particular competitive discipline of freediving.

What Is Constant Weight Freediving

Constant Weight Freediving is sometimes known as constant weight apnea. By definition, the word apnea means the temporary cessation of breathing. When it comes to constant weight freediving, a diver is required to descend into the water and ascend back to the top using only their fins or a monofin. The dive is performed along a dive line but the diver is not permitted to touch this line throughout the duration of the dive. The only point where the diver can make contact with the dive line is at the bottom of the dive when the diver turns around to begin the ascent back to the surface.

The entire trip from depth to surface again is performed without changing the weight of the diver. This means that you have to work against buoyancy as your dive until you reach a point of freefall. As you ascend to the surface, you have to work against negative buoyancy to reach to the top.

How Is Constant Weight Freediving Different From Other Forms Of Freediving

Constant weight freediving is a very specific method of freediving that focuses on maximizing the depth that a diver can reach in a single breath hold. Divers that practice this form of freediving are focuses solely on performance. Their goal is to go straight down as far as possible along the dive line and then return straight up to the surface. This form of freediving is often the format for competitions in which competitive divers work to see who among them can reach the deepest depth.

Other forms of freediving, by comparison, aren’t nearly as rigid in their format. Recreational freediving, for example, is a form of diving in which the diver can travel any which way while underwater. Also, these freedivers are often merely enjoying the scenery during their breath holds and exploration takes priority over the actual depth of the dive. This is why this form of freediving is preferred by causal freedivers in comparison to constant weight freediving. It is often seen as more enjoyable and relaxing by comparison.

How To Perform A Constant Weight Freedive

1) Get in a boat – If you are planning on trying constant weight freediving, you are going to have to go out into the water where it is deep enough to maximize your depth. Remember, the entire focus of this sport is depth, so you aren’t going to get much practice diving to the bottom of your neighborhood pool.

2) Drop your dive line – A dive line with a weight at the bottom is used for guidance as you descend into the water. As you go deeper, it becomes more difficult to see and maintain your bearings. The dive line will help with your orientation as you descend. Many freedivers will often link themselves to the dive line with a lanyard. The dive line also serves as a measuring tape to monitor your depth.

3) Strap on your fins – Constant weight freediving employs the use of a monofin typically but you can use bifins as well. The drawback from bi fins, however, is the loss of power and propulsion through the water. The main benefit of a monofin is the power that it generates as you undulate your entire body. Think about how fast and powerful a dolphin is as it cuts through the water. You get that same effect with a monofin. This propulsion cannot be replicated with bifins without exponentially increasing the amount of kicking while wearing the fins. Since we are trying to maximize our depth while still being able to make it back to the surface, it makes sense that a diver would use a monofin to maximize performance.

4) Have your dive buddy on standby – As with any form of freediving, you must always have a dive partner nearby. This is even more important with constant weight freediving because you may need assistance as you ascend to the surface. The last thing you want to become fatigued as you ascend and not be able to reach the surface.

5) Dive – Hold your breath and begin your descent along the dive line. You cannot touch the line or use if for assistance as you descend into the water. Just follow the line into the water until you reach your desired depth at which point you can use the dive line to turn around before you swim to the surface. At around 25 to 30 meters (80 to 100 feet), the water pressure will begin to overpower the buoyancy of the air in our lungs. This will allow you to enter into a free fall that will allow you to plummet deeper into your dive. However, it is important to remember that you will have to overcome this negative buoyancy as you swim to the surface.

Is Constant Weight Freediving Dangerous?

The short answer is yes. As with any sort of underwater activity, diving as deep as you possibly can into a body of water comes with risks. Of course, there are precautions that you can take to mitigate these risks. However, you can never completely be risk-free with this sort of activity.

Overstretching Your Limits – The overall goal of constant weight freediving is to dive as deep as possible without changing your weight. It should go without saying but whatever depth you dive to will have to be traveled a second time as your swim back to the surface. For many people, knowing where the “halfway point” of your breath hold is can be difficult to determine. The last thing you want to do is reach a dive depth only to realize that you are seconds away from gasping for oxygen. However, freedivers need to reach new depths in order to improve their dives.

How To Safely Improve Your Limits – The best practice for diving deeper is to do so gradually and under the supervision of a dive buddy or spotter. You should keep a log of the depths you have safely reached and then incrementally increase those depths. So, if it is your first time performing a constant weight freedive and you successfully make it down 20 meters (~ 65 feet), the next time you go diving, you can attempt 25 meters (~82 feet). Remember though, everyone will have a different capacity, so work within your limits.

As you descend to new dive depths, have your dive partner follow you to the halfway point and then remain at that point while you continue on descending. As you ascend to the surface, your dive partner can monitor you and check for signs of distress. You can also signal to your dive partner if there is a problem. In either situation, your diver partner can assist you back to the surface in the event that you cannot make it on your own.

Freediving Blackouts – These are a loss of consciousness caused by deprivation of oxygen to the brain specifically. This typically occurs at the end of a breath-hold and usually happens unsuspectingly to a diver because they haven’t actually felt the reflexive urge to breathe. Since they think that they still have time to maintain their breath-hold, they don’t realize that their brain is suffering from a depletion of oxygen and they lose consciousness unsuspectingly. If you don’t have a spotter or dive-buddy nearby, this could result in death.

How To Avoid Freediving Blackouts – The important thing to remember here is to take adequate breaks in between dive attempts. These blackouts are deceptive in that they can occur even when you don’t feel the stress from a desire to breathe. That is why you need to consciously oxygenate your body while at the surface. Just because you think to yourself, “Ok, I’m ready,” it might not be the case. It is not uncommon to take 10 or even 20-minute surface breaks in between freedive attempts to ensure proper oxygenation of the tissues within the body. Additionally, this is yet another reason to have a spotter nearby to monitor your behavior while executing your dives.

For more information on the dangers of freediving and what you can do to overcome them, click the link HERE.

Should I Use A Monofin Or Bifins For Constant Weight Freediving

Before you go out an purchase new equipment, you need to assess your goals. Constant weight freediving isn’t typically an activity that you can casually go out and perform at your leisure. You need transportation (a boat or some sort of watercraft) to get you out to water that is deep enough to accommodate deeper dives. You will also need a spotter to accompany you while you dive. For these reasons and more, constant weight freediving is a competitive form of diving that takes considerably more effort and commitment to perform. With this in mind, you shouldn’t rush out to buy new equipment for a new activity if you already have acceptable equipment in your possession.

If you have made the decision that constant weight freediving is something that you want to pursue, then choosing the right propulsion equipment is paramount for reaching your goals. The general consensus among competitive constant weight freedivers is that a monofin is superior to bifins. The reason being the amount of power that the monofin generates as you undulate your body. This amplified power translates to greater amounts of water displacement which, in turn, equates to greater propulsion of the diver through the water.

The importance of water displacement isn’t just important when diving to reach your desired depth. It is just as important when ascending back to the surface. As we mentioned previously, after you reach a depth of roughly 25 to 30 meters, the pressure being exerted by the water will overpower the buoyancy of your body and you will begin to free fall into the water. Once you are ready to turn around and make your ascension back to the surface of the water, you will have to work against that same negative buoyancy in order to rise to the surface. If you aren’t displacing enough water as you swim, you will not rise fast enough to reach the surface before gasping for air. This is another reason that constant weight freedivers prefer to use a monofin when pushing the limits of their dive depths.