What is visibility?

[Bob DBF]

They look at me like I’m nuts.

And...

There are a lot of things to do up on the NC besides dive, otherwise I might not have done as much diving as I have. Out of the three families that would go up and camp, there were two divers. Out of 9, with occasional hangers on, there was only two ab divers and out of that, I was the only SCUBA diver. We all would go at least once a month from May to September. Of course, aside from diving, if one dosen't like hiking the woods or beaches, small towns, tourist spots, or Dicks Place, the road goes to San Francisco as well.

Would you get adventurous and do a shore dive on your own? Even though the water is probably 52 degrees?

Oh yeah, and the conditions can change dramatically while one is burning a tank and enjoying the sights.

This is why nobody dives up here.

No tourist divers, that is.


Bob

 

[MaxBottomtime]

It also helps to know the area. Tourists may look at Monastery and think it's a baby dive.

By the time they exit, it could be back to normal.

 

[Eric Sedletzky]

And...

There are a lot of things to do up on the NC besides dive, otherwise I might not have done as much diving as I have. Out of the three families that would go up and camp, there were two divers. Out of 9, with occasional hangers on, there was only two ab divers and out of that, I was the only SCUBA diver. We all would go at least once a month from May to September. Of course, aside from diving, if one dosen't like hiking the woods or beaches, small towns, tourist spots, or Dicks Place, the road goes to San Francisco as well.




Oh yeah, and the conditions can change dramatically while one is burning a tank and enjoying the sights.



No tourist divers, that is.


Bob

I remember once we were ab diving at Stillwater doing a group fun dive thing. Stillwater isn’t a trophy spot but this was just meant to be a day of fun.
So we’re at the picnic tables cooking fresh abalone for lunch on a stove I brought, some beer battered and some panko’d. We also had the best local micro brews and wine opened.
Along come some Chinese tourists that don’t speak a lick of english, so I offered them a plate of abalone and I also had some fresh uni that I just gathered, big plump bright yellow and sweet. I wanted to show how genuinely friendly Americans can be. They were so grateful bowing with grins ear to ear. Asians are so cute when they’re happy. They were probably up for the day from SF. They got way more that they bargained for, what a treat!
I’m sure they went back with stories.

I used to do this a lot. I’ve met many interesting people in many walks of life through sharing fresh seafood cooked on the beach.

 

[Scuba Lawyer]

Would you get adventurous and do a shore dive on your own? Even though the water is probably 52 degrees? There’s a trail to climb you know.
How many people on SB are self sufficient enough and seasoned enough to dive a place like this, or anywhere anytime without any diving infrastructure, no guides, no babysitting, no dive shops.
I didn’t think so.
This is why nobody dives up here.

Obviously, my post was tongue-in-cheek Your assessment is correct (and my definition of a true diver - although I'm sure others will disagree ) I have made many happy solo scuba dives up and down the North Coast. Of course that was in my younger days. I'd probably need to enlist a sherpa to schlep my gear down the trails these days, but I would still go. I haven't been up there since the ab closure. Probably do a camping trip up there in May and visit my dive buddy who lives in Gualala.

 

[Bob DBF]

Along come some Chinese tourists that don’t speak a lick of english, so I offered them a plate of abalone and I also had some fresh uni that I just gathered, big plump bright yellow and sweet

Always nice to share with those that appreciate the gesture, and the bounty.

I'd probably need to enlist a sherpa to schlep my gear down the trails these days

Even back in the day, my buddy and I would talk about trying to find some native bearers, never could come up with any. Or dancing girls, couldn't find any of them either. I guess they only hang around in B movies, not on the NC.


Bob

 

[Eric Sedletzky]

...Or dancing girls, couldn't find any of them either. I guess they only hang around in B movies, not on the NC.

I might know a few, but whether or not you’d want to see them in a dancing getup is another thing

 

[TMHeimer]

Asians are so cute when they’re happy.

….

 

[clownfishsydney]

Don't know about what affects freshwater visibility, we have virtually no such diving in Australia apart from a few caves here and there.

As to the ocean, many things affect the visibility. Surprisingly, rainfall is (at least in Sydney), not that relevant except in the harbour or bays and even then, only after a week of very heavy rain (which we really have not had for years). The main factor is ocean currents. The East Australian Current runs down the coast from Queensland, bringing warm blue water. Sometimes it comes in so close it reaches the shore. This can bring 30 to 40 metre visibility, we get this perhaps once or twice a year. Strangely, southerly winds can bring clear water, it seems it blows the dirty top water out to sea (at right angles to the wind) and the warmer blue water comes in. At some places this happens like clockwork. Big seas can stir up the bottom and make the water dirty for days or even weeks afterwards.

As to how to measure visibility, I tend to work out how far I can see and identify a diver or dive site feature underwater. I measure using a diver as a length (about 2.5 metres from head to tip of fin) as a rough scale. For my logbook, I use the following scale:

• Sh!thouse - less than 2 m
• Very Poor - 2 to 4 m
• Poor - 4 to 6 m
• Fair - 7 to 10 m
• Good - 10 to 15 m
• Very Good - 15 to 24 m
• Excellent - 25 to 30 m
• Very Excellent - 30 m+

So far this year, 49 of my 59 dives in Sydney have been Good or better. This is an exceptional year for visibility, probably the best over the 31 years I have been diving.

Hope this is of interest.

 

[MaxBottomtime]

For Palos Verdes and much of California, I use a slightly different scale.

• Sh!thouse - less than 2 m but good enough for macro photography.
• Very Poor - 2 to 4 m average dive
• Poor - 4 to 6 m very good dive for close focus wide angle. One of the better days.
• Fair - 7 to 10 m About as good as it gets. This is when we dive as often as we can, knowing it won't last.
• Good - 10 to 15 m Once or twice per decade. Blue water wide angle photography.
• Very Good - 15 to 24 m One of the really nice days at Catalina Island
• Excellent - 25 to 30 m One of the incredible days at the outer Channel Islands.
• Very Excellent - 30 m+ Only topside, never underwater.

 

[Pipehorse]

I have been thinking about visibility a lot lately, I always estimate visibility when I write a dive report, which is frequently and posted at Blue Heron Bridge Trolls thread. I read some good explanations here, albeit subjective. But that's the thing, visibility is not very well standardized. Knowing the distance between stanchions of the fishing pier at BHB gives a good frame of reference. The first picture is when I entered the water at 1133 facing south, there is no handy frame of reference so I estimated the visibility at 50ft (Sealife Sportdiver iphone 12pro max f/2.4, 1/121sec, ISO-32, ambient light). The second image was taken at 1305 ( f/2.4, 1/30sec, ISO-200, ambient light). The stanchions underneath the fishing pier are located 33 feet from each other. The photo was taken from between third to last set of stanchions, facing west. So clearly the 2nd to last set of stanchions are easy to see at 33ft, the last set of stanchions are 66ft away, they are kind of shadowy but they can still clearly be seen. Also note that the majority image is in shadow not direct sunlight, sometimes when the water is a little cloudy visibility is increased by the shadow since glare is significantly reduced. What say you? Given distances in the second photo are known.