While we're on the subject ....
The Equipped To Survive site is a good source of info, and That Article about testing different signaling devises in the Scapa Flow is revealing
D_B:Here you go .. what equipment you need, what works best, and why you need it ...
D_B:EVERYONE ... you need to save this, a very good, if long, read on rescue trials in real world conditions, conducted in the Scapa Flow ... How far can you see me? ... http://www.jeanelaine.co.uk/diveraids/intro.htm
And this .. Equipped to Survive ... http://www.equipped.com/signal.htm
and the rest of the website is a treasure trove of info ... [URL="http://www.equipped.com/toc.htm"]http://www.equipped.com/toc.htm[/URL]
The Equipped To Survive site is a good source of info, and That Article about testing different signaling devises in the Scapa Flow is revealing