goin' down ... descent tips for newer divers

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MXGratefulDiver

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Someone asked in another thread about tips on descent technique. Here's mine ... I'm going to describe it in a lot of detail, so you can visualize the descent while I'm describing it.

I'll start out by pointing out what I've noticed to be the most common problems newer divers have when trying to descend.

- breathing
- inadvertent fin kicking

Both of these problems will have a tendency to hold you up while you're trying to go down, and so you won't be able to descend. The most common resolution most people will try is simply adding more weight. OK, so that'll get you down ... but then you'll be doing the whole dive with too much weight, and that tends to make you work harder and burn through the air in your cylinder faster.

So let's focus on a better solution ... which involves better breathing techniques, and avoiding kicking or sculling actions that inhibit the descent.

Let's say you're descending down a buoy line. You're at the buoy, you make eye contact with your dive buddy and you give each other the descend (thumbs down) signal. You raise your inflator, preparing to vent your BCD and begin your ascent. Now what?

My suggestion at that point is that as you are letting air out of your BCD, take a deep breath and hold it for a moment. Go ahead and keep venting your BCD, but don't start breathing out until you are about eye level with the water. Then start a looooong, slow exhale. And just about the time you think you've exhaled fully, exhale some more. Most folks are surprised at how much air they still have in their lungs. Think of your lungs as just another BCD ... you want to vent ALL the air out of it on the descent.

By doing this, you'll find yourself several feet beneath the surface before it's time to inhale again. By then, the water pressure around you will be compressing your exposure gear, and you won't need to compensate for all the buoyancy of the suit (if you inhale too close to the surface, this tends to send you back up again).

Now, while all that's happening, what are you doing with your feet? Newer divers tend to kick when descending ... most times they don't even realize they're doing it. That's the "hard-wired" part of your brain telling you that you're doing something you weren't designed to do (go underwater) and taking appropriate action to rectify the situation. You need to rearrange your wiring so your brain doesn't give that response. The best way to do that is to cross your feet at the ankles. It won't stop that unconscious part of your brain from making your feet flutter ... but it WILL make it so that you notice when it starts to happen, and the conscious part of your brain can take control of your body and stop doing it.

Once you've gotten down a few feet and taken that first breath, you can uncross your ankles. That's a good time to think about getting horizontal for the remainder of the descent. The easiest way to do that is to simply extend your legs and point your fins back (think ballerina). As you descend, the motion of your body in the water will push on the tops of your fins and naturally start rotating your body. Go with the flow ... you'll almost "fall" into a nice, horizontal position. So what does this do for you? Well, for one thing, it helps you see where you're going ... you can more easily see the bottom as you approach it. Also, being in this "skydiver's" position helps control the speed of your descent. Keep your hand on your inflator hose and add short "puffs" into your BCD to regulate the speed of your descent.

As you approach the bottom, make use of your "built-in BCD" once again by taking a nice, deep inhale. That'll slow you down and help you come to a stop without having to use your inflator button (or the bottom) as a hard brake. Once you've inhaled, slowly exhale while adding a few more "puffs" to your BCD to maintain your position.

Using this technique will have a few advantages ... it'll make it possible for you to descend with the minimal weight you need to control your dive ... it'll help you maintain a regulated speed and eye contact with your dive buddy on the descent ... it'll help you learn to control your depth without using your BCD inflator as an "elevator" button ... and it'll keep you from plowing into the bottom at the end of the descent.

... Bob (Grateful Diver)
 
I'll have to pay attention and see if I unconsciously kick while descending this weekend. I like the idea of rotating horizontal during the descent as well, and I'm going to play around with that technique also.
 
First of all great post nwgratefuldiver!

I want to add a little something something;

Dont forget to check if your buddie is Ok during the descend! And ofcourse an ok sign after setteling down in a nice hoovering position at the bottom.

Best regards, Pitchblack.
 
Go with the flow ... you'll almost "fall" into a nice, horizontal position. So what does this do for you? Well, for one thing, it helps you see where you're going ... you can more easily see the bottom as you approach it. Also, being in this "skydiver's" position helps control the speed of your descent. Keep your hand on your inflator hose and add short "puffs" into your BCD to regulate the speed of your descent.

Another good post Bob.

I'll just add that descents are where many buddy separations happen. Someone who has trouble equalizing or has a mask leak or other gear problems tends to forget they have a buddy and the buddy happily descends and then discovers their buddy is nowhere in sight.

Pay close, really close attention to your buddy during descents and be ready to offer the quick fix of minor gear issues. Have your buoyancy under control so that you are not descending so fast you can't offer the needed assistance.

Frankly, I'm surprised at the number of divers that still descend in a vertical or heads up position.
 
Another of your great informative posts, Bob!

I found that in descending it is best to descend either vertically feet first or (my preference) horizontally with arms and legs spread a bit to break the descent. I adopted the latter descent mode after having a tank valve clog with internal debris following a head down descent. Never expected a tiny piece of "dirt" to enter the debris tube and leave me without any gas flow at 75 feet.
 
Great writeup, Bob.

I'd add this mantra that is true for most everything underwater: slow is fast and fast is slow.

Many people want to get down as quickly as possible (this is especially true when breathing expensive gases). But if you go so fast that you have to come up again to equalize, you're shooting yourself in the foot.

Try to descend at a controlled rate so you never blow past the ability to equalize. Personally, I equalize with almost every exhale as I descend until about 30'.
 
Great post! Comparing the diver's descending position to a sky diver is a great visualization.

Going horizontal also reduces the possibility of the diver literally going over backwards and leading with his or her butt.
 
Good post... Thanks... but I can't resist telling a very funny (at least it was at the time) story.

I used to work at an LDS (now partly owned by the guy I'm referring to in this story.) The name has been changed to save him the embarrassment... but he was supposedly a Navy Diver and according to the website.. instrumental in the recovery of the Atomic Bomb off Rota Spain.

In any event, I was "in charge" of the quarry on this particular day. I was standing at the top of the hill (talking to a couple of people) overlooking the entry beach when I heard a bunch of splashing and grunting. It sounded like someone was in trouble... so I looked over the edge of the hill and saw this diver flailing around on the surface in what appeared to be an attempt to descend. I quickly noted that His BCD was fully inflated. I waited for him to pop his head up out of the water then yelled down to him...

"Hey Joe, what are you doing down there." He turned around and yelled back "I'm testing out this Nitrox I just got certified on."... So I yelled back... "Why are you splashing around on the surface?"
To which he replied, "I can't get down... I think it's something to do with this Nitrox or something!"

To which I replied..." Joe, let some air out of your damn BC!"

He let some air out and down he went... We can all sleep better knowing Joe now teaches students to dive... and maybe even teaches them the benefits of Nitrox!

Sorry... that's another thread ...

Nitrox has no effect on buoyancy... but as Bob pointed out... kicking your fins does, having a partially inflated BCD does, anxiety does (just relax,) improper weighting does, type of water (salt vs fresh does,) the thickness/material of your wetsuit/drysuit does, type of tank does (steel vs Aluminum,) etc..

The "skydiver" descent is the best descent to use... been teaching that for years from pool one...

Thanks again Bob for a great post.
 

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