You never know when you will find yourself in it….BLACK WATER!
Visibility in water is generally referred to by horizontal and not vertical; this is a very important piece of information because it does affect the way visibility is expressed. Another important piece of information is what affects visibility. The two primary factors that affect visibility are suspended particles and light penetration through the water. For the most part, few divers enter into water that has zero visibility, but a select few do. Zero visibility is general defined by visibility as far as the end of arms reach to not being able to see your hands in front of your mask.
Diving in zero visibility is more of a mind game than anything else, but there are a lot of techniques and skills that are needed to perform these types of dives as safely as possible. The skills and techniques are not part of any sport level course such as open water certification, and they should never be learned without a trained professional supervising closely.
Just the entry into water with zero visibility can present some pretty dangerous possibilities. There have been several documented cases where divers performed improper entries and drove their legs knee-deep into soft mud and could not reach the surface unassisted. There is also the problem of not being able to see what is in front of you or over your head. Many lakes and reservoirs are man-made and have trees still standing just below the surface which present a long list of dangers for the unsuspecting diver.
The ERD 1 diver course addresses these issues and teaches the needed knowledge and skill sets to perform these types of dives in these conditions.
A common training practice, under properly trained supervision, is to simply have divers run a simple compass pattern and watch to see how often “the heads pop up.” The overwhelming claustrophobic feeling is just too much for some to handle or overcome. Don’t worry; Tenders are just as important on dives like these. On the other end of the diver spectrum is the diver that, while running the compass course, only surfaces after “running aground” in the cat tails and duck weed to raise their heads grinning to exclaim…”ran out of water!”
Wondering which diver best describes you? Get out with the Team and do some training…first chance you get!
For assistance preparing and scheduling training for your Team contact ERDI
http://www.tdisdi.com/wpsite/erdi/ or call 207.729.4201