DON’T GO DEEPER THAN NECESSARY
This might sound an obvious piece of advice but it is very common for divers to go deeper than they need to do, particularly at the beginning of a dive.
Only go deep if there is a purpose to it. After all, the deeper you go, the greater your uptake of inert gas, and the more inert gas your body will eventually have to discharge.
For example, you drop into the water to do a wreck-dive, expecting to be above the wreck. You look down and there is no wreck in sight. The seabed is at 30m and you know that the wreck rises 15m above the seabed. The visibility is very good. If the wreck were there, you would see it.
You look at your guide, who is descending below you. He is pointing into the distance. You look and you can’t see anything, but you guess that the guide is indicating the direction in which the wreck lies.
Go deep only if there is a purpose to it. Image: Andrey Bizyukin
You are at a depth of around 10m, having stopped descending when you noticed that you were in the wrong place. The guide is below you, close to the seabed, but still well in view. What do you do? Do you drop down and join the guide?
No, the best thing is to stay at around 10m and swim in the direction the guide is indicating. The deeper you go, the more air you consume, the more no-decompression time you use up, or the more of a decompression burden you accrue, and for no purpose.
If the guide is right, in the prevailing conditions you will see the wreck when you get close to it, and then you can drop deeper to explore it.
If the guide is wrong, you have not wasted time and air at depth and have plenty of time to try to locate the wreck in a different direction.
Guides should know this too, but if they choose not to exercise commonsense and go deep for no reason, this is not your problem (though it might become your problem if they run low on air or go into deco, or both).
Nor should you feel obliged to follow them just to keep them company. And, if there is a good reason for them to have gone deep early, they should have mentioned it in the dive-briefing.
Of course, if conditions change and visibility drops, so that you begin to find it difficult to follow the guide, and fear that you might not see the wreck from your current depth, drop deeper.
Another circumstance in which you often see divers going deeper than necessary is on an early-morning dive on a slope or a reef wall. The angle of the sun at that time of day is such that only the top section of the reef is well-lit. Further down, the wall or seabed is dark.
Unless you are planning to carry a light and treat the dive like a night-dive, there really is little point in swimming along below the well-lit zone. There is also absolutely no need to go very deep simply because it’s the first dive of the day.
Next month I will outline a few more defensive-diving strategies.