Diving Myths: Neutral buoyancy or adios fin pivots

No I don’t mean that neutral buoyancy is a myth although some people would seem to think otherwise. In fact, this is going to be the first in a series of blogs about diving myths and in particular concepts and techniques that are very commonly taught by instructors. They’re not necessarily wrong but they are often taught as though they are gospel and anyone not adhering to these tenets will find themselves in 100m of shark infested, black water as their gear explodes apart in a terrifying current. Or, having a few issues with their buoyancy control. One of the two anyway.

This time I’m going to have a little look at neutral buoyancy as taught at Open Water level.

One of the things we often do as instructors is teach people in confined water whilst they are very negatively buoyant. We glue them to the bottom of the pool with lead and then proceed to get them practising out of air and mask skills. Of course the reality is that most dives don’t take place kneeling on the coral reef for 40mins (dependent on nationality and training agency of course). Therefore these issues are much more likely to present themselves as the diver is swimming along so it makes more sense to practice them whilst neutrally buoyant.

One of the new features of the PADI Open Water course is an increased emphasis on neutral buoyancy throughout the confined sessions as well as open water.

Now I completely understand the argument of ensuring that floating about the first time they perform these skills doesn’t distract divers but I think there is a little confusion over precisely what is meant by neutral buoyancy as a skill. One instructor asked me whether the new open water course meant that all skills had to be done whilst the students hovered. I think for most students that would ultimately end up with a reaction like this:

Let’s have a little look at the new performance requirement:

  • Use low-pressure BCD inflation to become neutrally buoyant. Gently rise and fall in a controlled manner, during inhalation and exhalation.

First off, neutral buoyancy is not hovering. Neutral buoyancy as a skill is what we used to call the ‘fin pivot’. Originally the fin pivot was thought of as a good technique to teach the concept of neutral buoyancy. However what the PADI examiners were finding is that instructors were becoming fixated on the perfection of the fin pivot as opposed to the actual performance requirement of demonstrating neutral buoyancy. Therefore they decided to revise the skill to remove any mention of a fin pivot and simply made it about being neutrally buoyant with an appropriate contact on the bottom. Now with the new course, point of contact is removed as well. What this essentially means is that as long as the diver is rising when they inhale and lowering when they exhale they have met the performance requirement- the essence of being neutrally buoyant.

However, the fin pivot is still very commonly taught at open water level (it’s not wrong to teach it) but I would argue that with the arrival of the new course it’s time for it’s use as a training technique to go.

Fin Pivot

A fin pivot yesterday: Demonstration is normally accompanied by much exaggerated hand gesturing towards how wide the instructors legs are spread …

Besides the issue of occasionally focusing on the wrong areas the other problem with the fin pivot is that it doesn’t really help divers achieve good trim. Trim is also emphasised in the new course, specifically that the divers should be able to maintain a horizontal position in the water. This is in contrast to older manuals where hovering vertically was emphasised. There’s no doubt that this has filtered down from tec diving where good trim is essential but it’s a great idea for a recreational diver to be in a horizontal position: It’s more efficient, it allows you to respond quicker in emergencies and it also keeps your fins off the reef and you can get closer to the cool stuff.

Now we don’t need open water divers to hover in full tec trim without twitching a muscle but we do want to help them get into a better horizontal position.

So what do you need to do as an instructor teaching the new course?

As far as the neutral buoyancy skill goes, I would ditch the fin pivot. Brief the skills based purely on the emphasis of the inhalation and exhalation so they should stay in a kneeling position. Don’t worry too much about the perfection of whether their knees touch the bottom when they exhale. You’re basically looking for them to rise as they inhale and gently lower as they exhale (not crash back down after a very slow small rise). Also, brief them that once they have achieved it to your satisfaction they should stay like that for the rest of the session. They are still making a contact with the bottom but just gently rising and falling as they go. They can then do their other skills at the same time. You may need to use judgement as to whether to get them to become negative again on some skills so they can concentrate on those performance requirements.

Ultimately this means that when the hover comes around they should only have to add a small amount of air, if at all, to go into the hover. Brief them to try and hover horizontally and then if their legs swing straight down you can help them get horizontal. A few tips you can use for this are as follows:

  • Get them to move the camband lower down the tank. That whole thing about having the top of the jacket in line with the top of the valve doesn’t really help matters all that much. I actually dive with the tank valve much higher up. Yes it means I can knock my head against it by leaning right back in the water but it makes horizontal trim much easier.
  •  Try moving weights higher up the body to bring their centre of gravity forward. You don’t need weights distributed all over the body like ankle weights, it’s all about centre of gravity. Try BCDs with trim weight pockets near the camband or integrated weights. If not, simply get them to bring the weight belt much higher up their waist. When they’re horizontal it won’t slip down.
  • Tell them to make the effort to keep their legs up, dip their bodies forward, whilst keeping their heads up and eyes ahead and move the weight belt once horizontal to keep it in position.

You’re then looking to see that they can hover  and maintain position using their lung control although I personally don’t have an issue with a small amount of leg movement if it’s just about keeping their legs horizontal and stopping them swimming into the wall of the pool. What you don’t want to see is that they are kicking to stay off the bottom. Also, please stop the buddha position stuff. Noone hovers in a buddha position and it’s downright useless for drysuit divers. Yes buddhism is the nicest of all religions but it still doesn’t belong in school and buddha hovers don’t really belong in diving. It’s much better to start someone down the road of hovering in a horizontal position than seeking a perfect hover in a position they’ll never use.

Buddha

Even Buddha says no to buddha hovers.

Do all of these things and you should find that when you head to open water, buoyancy comes a little easier to your students, which makes the open water sessions much more fun for everyone involved, including you!

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s