I've been chatting with a number of other dive professionals, and it seems like a common theme that, although new divers are impressed with the importance of controlling the rate of ASCENT (to avoid AGE and DCS), all too many are just relieved to be able to get underwater, and never practice any kind of descent control. Given that ear barotrauma is the most common injury in new divers (and have any of you had sore, crackling, or muffled ears after an early dive?), it seems as though some tips on controlling descents would be useful.
I know that, when I was a new diver, just getting under the surface was a huge challenge. Like many, I wasn't underweighted; I was under-techniqued. I didn't balance well at the surface, so I kicked constantly. As a result, when I let the air out of my BC, the kicking I was doing was keeping me at the surface. Adding weight to overcome that resulted in too much air in my BC at depth, and very dubious buoyancy control. In addition, I did what I understood of what I was taught -- I initiated my descent by venting my BC and exhaling . . . with the result that, when my head reached the water, I had a desperate need to INHALE, and therefore buoyed myself right back to the surface. If I was successful enough to get down, it was by virtue of being relatively overweighted and not kicking -- and as a result, the minute I got underwater, I began to plummet, often rotating onto my back.
That story illustrates a lot of points about how to do descents better. To begin with, you need to find a way to balance at the surface that doesn't require constant kicking -- either that, or when you decide to initiate a descent, you have to STOP that kicking. This can be done by crossing one's legs, which prevents the kicking motion. A slight bend in the knee at the same time, which often COMES with the leg crossing, will tend to put your fins out behind you. Resistance from the water will then tend to rotate you into a horizontal position as soon as you are just a few feet underwater. This is advantageous, because in this position, you have the greatest resistance to the water in continuing to descend.
Also, if you hold up the inflator hose and begin to vent and INHALE, then when your head reaches the water, you can exhale sharply, and that will continue your descent. This works much better than the other coordination.
Once you are horizontal and descending, you need to continue to exert control of the descent. I found the easiest way to manage this was to remember that each time my ears needed air added to them, my BC or dry suit did, too. It is a VERY good drill, if you have some kind of wall or line to watch while you descend, to arrest your descent every ten feet, just to prove to yourself that you can. In addition, if you do this, you cannot get more than 10 feet from your buddy, even if he is having descent problems of his own. When the two (or three) of you can head down, stop at 10 feet and okay one another, and then continue the descent, you will not leave someone with ear problems behind, and you will not abandon someone with a gear problem that only became apparent underwater (like an LP inflator hose that pops off!).
I think a lot of folks will be very surprised at how difficult it is to control a descent like this -- I know I was, the first time someone asked me to do it! But developing this kind of control will make one a much better buddy, and avoid a great many problems of buddy separation -- and also the anxiety and sometimes barotrauma that occurs when the person left behind is desperate to regain contact with his buddy.
I know that, when I was a new diver, just getting under the surface was a huge challenge. Like many, I wasn't underweighted; I was under-techniqued. I didn't balance well at the surface, so I kicked constantly. As a result, when I let the air out of my BC, the kicking I was doing was keeping me at the surface. Adding weight to overcome that resulted in too much air in my BC at depth, and very dubious buoyancy control. In addition, I did what I understood of what I was taught -- I initiated my descent by venting my BC and exhaling . . . with the result that, when my head reached the water, I had a desperate need to INHALE, and therefore buoyed myself right back to the surface. If I was successful enough to get down, it was by virtue of being relatively overweighted and not kicking -- and as a result, the minute I got underwater, I began to plummet, often rotating onto my back.
That story illustrates a lot of points about how to do descents better. To begin with, you need to find a way to balance at the surface that doesn't require constant kicking -- either that, or when you decide to initiate a descent, you have to STOP that kicking. This can be done by crossing one's legs, which prevents the kicking motion. A slight bend in the knee at the same time, which often COMES with the leg crossing, will tend to put your fins out behind you. Resistance from the water will then tend to rotate you into a horizontal position as soon as you are just a few feet underwater. This is advantageous, because in this position, you have the greatest resistance to the water in continuing to descend.
Also, if you hold up the inflator hose and begin to vent and INHALE, then when your head reaches the water, you can exhale sharply, and that will continue your descent. This works much better than the other coordination.
Once you are horizontal and descending, you need to continue to exert control of the descent. I found the easiest way to manage this was to remember that each time my ears needed air added to them, my BC or dry suit did, too. It is a VERY good drill, if you have some kind of wall or line to watch while you descend, to arrest your descent every ten feet, just to prove to yourself that you can. In addition, if you do this, you cannot get more than 10 feet from your buddy, even if he is having descent problems of his own. When the two (or three) of you can head down, stop at 10 feet and okay one another, and then continue the descent, you will not leave someone with ear problems behind, and you will not abandon someone with a gear problem that only became apparent underwater (like an LP inflator hose that pops off!).
I think a lot of folks will be very surprised at how difficult it is to control a descent like this -- I know I was, the first time someone asked me to do it! But developing this kind of control will make one a much better buddy, and avoid a great many problems of buddy separation -- and also the anxiety and sometimes barotrauma that occurs when the person left behind is desperate to regain contact with his buddy.
