Divers' Dreams - Limited Visibility

Tips on Diving in Limited Visibility!

Note: The following tips are just guidelines in handling yourself in limited visibility. It is by no means the "rule of the thumb" for diving in limited visibility. Proper training and equipment must be adhered to and feeling confident about your own ability in handling low visibility will also be of help.

Diving in limited visibility, firstly, you have to be prepared like on any other dives. Besides your usual equipment, a compass is a must and a buddy line would come in very useful for the more extreme conditions. Getting comfortable with the environment and being aware of the hazards and of course, mastering the basic diving techniques.

Diver disorientation is very common in limited visibility due to the limited amount of visual references. Anxiety may build up and that will eventually lead to panic if not overcomed. To avoid these situations, divers should always have some form of visual references from the start of the dive to the end. It could be the anchor or mooring line, or even the reef slope as you descend. This could help reduce anxiety as you can then gauge your speed of decent and monitor your depth. Descending feet first will also help in avoiding disorientation.

As you approach the bottom, don't go crashing into it! Many times I have seen divers reached the bottom and start kicking their fins to try to keep off it. By doing so, they stir up the sediments and cloud up the area. One moment it is decent visibility and the next, zero visibility. If that happens, keep as still as possible without stirring up even more clouds of sediments. Hold on to your buddy and keep yourself focused on an object - buddy, gauge, rock, etc. Try to determine which direction the current is flowing and swim into it. That would get you out of the cloud of slit. To avoid stirring up the bottom as you approach it, stop a metre or so off the bottom and get neutral, orientating yourself to the direction you want to go and move off from there.

Finning along the bottom or along the reef, most divers don't know or don't care what goes on behind them because all that matters to them is what they see in front. Fins are the main cause of divers stirring up the bottom. It might not concern you too much if you are just headed in one direction but what if you have to turn round and head back from where you came? Then you would be swimming in your own cloud of silt. Also, think of the divers that might be following behind. The best way to fin would be to fin gently to avoid stirring up too much. When I have to be close to the bottom or moving over a sandy or silty area, I would usually "scull" - finning sideways instead of the usual flutter kick. It's slower but speed is the least of your concern when diving in limited visibility.

Another concern when diving in limited visibility, is losing your buddy. One moment you see your buddy beside you and the next moment you turn around, your buddy has disappeared! Sounds familiar? A properly planned dive like establishing your depth and direction and setting your compass accordingly, discussing with your buddy as to how you plan to keep together and keeping a lookout for your buddy every now and again will help avoid buddy separations. Another way to avoid buddy separations is to hold hands but I think those macho guys with their macho buddies might find this a little awkward. That's where the buddy line comes in useful! Preferably between 2 to 3 metres long. Any longer and it can cause entanglements.

Surfacing is another concern. Surfacing too fast or an uncontrolled ascent might result in embolism or decompression illness. If you are coming up on the reef slope, watch the reef and your depth gauge and slow your ascent. If you are in mid-water with no references, watch your depth gauge and your bubbles, making sure you do not surface faster than the bubbles you are blowing out. If you are using a computer with an ascent warning signal, watch or listen for the signal and surface as slowly as possible.

This is an extract of an article by David Wong, published by Decom Stop magazine March/April 1999.