How is “visibility” defined?

[jeckyll]

One of the sites I dive has fresh water runoff. Viz in the first 10 feet is often < 3 feet, but lower it much better.

I know some people define visibility as the distance at which you can distinguish a diver from other objects. *shrug* I usually define it as "good" or "bad"

Bjorn

 

[MXGratefulDiver]

I know some people define visibility as the distance at which you can distinguish a diver from other objects. *shrug* I usually define it as "good" or "bad"

Bjorn

That sounds similar to my method for determining the size of an octopus ...

... they are either "small", "medium", "large", or "FREAK'N HUGE!"



... Bob (Grateful Diver)

 

[dpbishop]

Viz is the distance at which you can see differentiate the lobster from the background.

 

[archman]

Even secci disks are pretty subjective. They're calibrated for the english channel.

 

[lamont]

viz is whatever produces the best reaction to the other diver you're talking to...

its kind of like the 2 knot currents that divers frequently swim into in their post-dive stories...

or the 8 foot long ling cod...

or the 600 lbs GPO...

and it always gradually gets a little bit worse or better the more times the story gets told...

 

[jeckyll]

That sounds similar to my method for determining the size of an octopus ...

... they are either "small", "medium", "large", or "FREAK'N HUGE!"



... Bob (Grateful Diver)

Bob: I've been hoping to see an octopus. Any size will do really. No luck yet! I was going on a night dive tomorrow, but now am getting a sinus cold and had to cancel. Which is really a shame because the viz was excellent on Sunday (And here I've managed to not totally hijack the thread, as we are back to viz )

Bjorn

 

[jagfish]

Here's my experiece...

Call up a for-profit dive site or boat operator and ask. Then divide that figure by 2, and that's about how far you'll be able to see...

 

[Dive-aholic]

Remember that horizontal viz and vertical viz can sometimes differ greatly at various locations.

Typically this is influenced by depth and ambient light.

Definitely agree. I estimate viz horizontally, not vertically. I've been at sites where I can see the surface from 20 feet down, but only had about 5 feet of viz horizontally. Then you drop below the thermocline at 30 feet, can't see the surface anymore, but viz is 30 + feet.

 

[CBulla]

Two of my fav dive sites, two different ways of looking at it!

Viz at Venice Beach, FL - "What bottom.. ohh my nose!" = what viz?? dive by braille!
Viz at Venice Beach, FL - "can I see the bottom well enough to find teeth, yes?" = OK, but tough on the eyes, sometimes disorienting
Viz at Venice Beach, FL - "I can see the bottom and my buddy!" = Must be 3 to 5 foot area, which means blackouts when a cloud goes overhead. A good day to dive!
Viz at Venice Beach, FL - "Woah! Look at all this life! Oh, and I can see the Law Enforcment AND civilian boat undersides and props as they recklessly drive over my FLAG!" - vis must be 8-20'! Look out for manatee's, turtles, dolphins and other such stuff that'll swim in for a look at ya to! AWESOME day to dive!

Viz at Lauderdale by the Sea, FL "I hear my buddy, where is s/he?" = Bad day - you'll find the reef with your face - nearly dive by braille.
Viz at Lauderdale by the Sea, FL "I see my buddy/group all around! Hey, there's a 9" lobster and its out of season! See you @ mid-night opening day!" Good day, vis is 20-50!
Viz at Lauderdale by the Sea, FL "Hey.. whats that in the distance?? The reef seems to just go on and on!!" Vis is 50-100'! Excellent day to dive.. you might even see the Bull sharks swimming parallel to you in the curtain checking out the noisy thing in their territory!

 

[Blox]

What's viz got to do with it..

Wasn't that a Tina Turner title back in the 80's?