Re: [PSUBS-MAILIST] Diver lights and visibility

[MerlinSub@t-online.de (Carsten Standfuß)]

I use a white/ slightly blue pocket flash on my scuba diver bottle, 
and the same flashlight with a orange acrylic cover on 
Sgt.Peppers.  It runs up to 15 hours with new batteries.

Table of
Distance of absorbing and diffusing of 
different color lights in clear water: 

1.) wave length in air 
2.) color discription
3.) distance in metric were the half of the light brightness
    is gone by absorbing and diffusing 
4.) same as point 3.) but in feet

1.) 		2.)		3.) 		4.) 
400 nm		violett		 8,66 m 	28,4
450 nm		blue		17,33 m 	56,8
500 nm 		blue		18,23 m		59,8
550 nm  	green		14,70 m		48,2
600 nm		yellow		 3,53 m 	11,6
650 nm  	orange		 2,22 m		 7,3
700 nm  	red		 1,18 m 	 3,9

this table indicates that maybe blue at 500 nm is the best choise
and the orange cover is a stupid idear.. but looks nice - 
special on the surface .. - Carsten - 

"Michael B. Holt" schrieb:
> 
> What color lamps are used as markers for divers outside the boat?  Is
> there a color that can be seen at a greater distance underwater?
> 
> Mike