Visibility Guess

[Zoomer]

I have a question, let say you go on a dive and you guess the vis is about 15 feet...
Lets say you are diving with a group of other divers here.
What does 16 feet vis mean to you?

a) You can plainly make out an object at 15 feet. (you can see a diver, tell it's a diver and can see exactly who it is)

b) You can see the object at 15 feet and can tell what it is but but can not see details? (you can see a diver, tell it's a diver but do not know who it is)

c) You can just make out that there is something at 15 feet from you.

 

[miketsp]

This question must have been asked dozens of times.
Do a search on
visibility secchi

and you'll get lots of threads like this one
http://www.scubaboard.com/forums/basic-scuba-discussions/118139-how-visibility-defined.html

 

[Eileentk]

Option c is what I generally use. I saw the post on the Secchi disc (learn something new everyday) and it gave me the idea to get one of these things and mount it in one of our local quarries. Unfortunately I'd have to get a bunch of them since the local viz is different above and below the thermocline and some areas of the quarry have less silt than others, etc.

 

[TSandM]

It probably doesn't matter much, because none of us can measure the distance accurately enough to make it meaningful (unless you're compulsive, and take a knotted line down and measure!) But I call it visibility if I can recognize signals from another diver at that distance, because that's what I really need from the viz.

 

[String]

If i can see my buddies whole body its about 2m.
If i can see half of him its about 1m

If i can see my buddy AND a bit in front of him its 3m.

If i can see further than that i get scared.

Seriously - it is easier to judge low vis than high vis as you can break it down into how many known size objects can fit into the view you can see.

 

[dbulmer]

String,
"If I can see further than that I get scared" -

LOL I demand to know where you're getting such brilliant vis

 

[String]

LOL I demand to know where you're getting such brilliant vis

Egypt

(got my first sea dive of 2008 in yesterday after 21 cancelled due to weather. I could see to my elbow therefore it was about 1-2ft)...

 

[dbulmer]

Did my first sea dive on twins 2 weeks ago in Eastbourne - about 1.5 metres vis but by God it was dark I've yet to have a good vis dive out of Eastbourne.

 

[TSandM]

String, that bug is hysterical! Both my husband and I tried to kill it . . .

 

[JeffG]

String, that bug is hysterical! Both my husband and I tried to kill it . . .

Good.


I'm not the only one.