How to rate visibility

[irishsquid]

I'm lucky that most of my dives have been in quarries with decent vis. The few springs and reefs have had exceptional vis, and good vis on wrecks in NC. With that said, unless it's an exceptional day on the river or lake locally, then it's more like; "Vis, what's that"?

 

[TSandM]

Typical Puget Sound viz is in the ten foot range, and 20 feet is where we start to sigh with pleasure and write posts on our local board about how good the viz is. Bad viz is when you hit the bottom before you see it, and when it's like that, I turn around and go out to lunch instead.

What's really interesting is how you estimate the viz. To me, bad is, as I said, hitting the bottom before seeing it, and having to dive with my nose almost ON the bottom to know where it is. Normal viz is swimming shoulder to shoulder with a buddy, just far enough apart that we can both frog kick, and being able to see him . . . but if he strays a bit, he gets fuzzy real fast. Good viz is being able to be ten feet or so from my buddy and still see him clearly, and still have light signals work well. ANYTHING over that is fantastic viz, and I don't care where I am -- except in a cave, where I really don't like viz that's reduced at all, unless the cave is small enough that you can see the walls anyway.

 

[Walter]

Depends on the location. At Venice 10 feet is excellent and I'm really happy with 6. In the Keys, 10 ft sucks.

 

[Garrobo]

Can see= GOOD
Can't see= BAD

 

[currier]

Any day of diving, no matter what the conditions, is better than a good day on land, IMHO.

I couldn't have said it better myself.

I'm extraordinarily fortunate for visibility ... average 10m, with the best I've seen locally +40m.

I get into conversations with my father (who gave up diving approx. 20 years ago), and I can't get over the conditions he saw every weekend. St. Lawrence and and Great Lakes 2m - 4m?

 

[emoreira]

Bad visibility - Local quarry Colonia Uruguay :

Good visibility - Emerald Reef Miami Beach USA :

 

[jimthediver]

Back when I was diving deep Lake Huron wrecks (pre zebra mussels) we would consider 10-15 good vis. Every once in a great while we would get down there and find 25+ visibility. That would usally result in an instantaneous change in the dive plan from penetrating exploration or whatever else we were going to do and we would go on a grand tour above decks instead. In 1987 "Jan the diver" became my permanent dive buddy. Jan's idea of poor diving conditions is a cloudy day on Grand Cayman (no really she's not that bad....but close). We predominantly dive in the tropical Pacific now and we start whinning if the vis gets much below 50-75 ft. Yes, we are spoiled!

Live to dive, dive to live!

 

[elmer fudd]

What's really interesting is how you estimate the viz..

Nobody ever seems to have a real definition of visibility. If you can see your buddy as a dark shadow in the water 4' away, does that mean you have 4' of vis? How about when you can see your hand out in front of your face, but not your fingers? I notice that when people here talk about 6' of vis, what they are usually referring to is the distance that they can see details at. Usually I find that I can see things like divers, lights and bubbles at up to 12' in what they would call "6' viz". I might not be able to tell anything more than that, but I can see the outlines.

Another thing I find is that people have a tendency to understate the visibility. When someone tells you there is 5' of vis, chances are it's really 8. What they're really saying is, "it was pretty murky down there", but since nobody actually did any measurement, they SWAG it and give an answer that they think reflects crappy vis.

 

[TSandM]

There IS a formal definition of visibility, using Secchi discs, but nobody ever does that. I think the convention in Puget Sound is that if the viz is kind of average, it's 10 feet. If it's pretty good, it's 20. If it's godawful, use a low number, with the lower the number the more emphatically godawful it was.

 

[Walter]

There IS a formal definition of visibility, using Secchi discs, but nobody ever does that.

Hey, I've done it.