Tough dive today in LOW vis (long)

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Saltair

Contributor
Messages
141
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0
Location
Penn Bay, Maine
# of dives
25 - 49
I posted here a couple days back about kicking in silt. I was back in that harbor today looking for a guys mooring, it was cut off by ice over the winter, and if I thought it was bad before I was wrong. I dont have a lot of dives, 25 or so, all in the ocean. What I saw today maybe common in lakes, but I had not run across it before, and was somewhat surprised by it. There were sratified layers of silt in the water column that created the illusion of being at the bottom. The actual water depth was only 14 or 15 feet. Surface Vis wasn't great, but not bad for around here, but as we approached the 1st layer at about 8 feet there was a dramtic drop in vis, and then from about 10 or 11 feet to the bottom there was a suspended sediment that reached all the way to the bottom making it essentially invisible. It was very hard not to swim into it which of course took limited vis down to zero, but once suspended above it you had to be only inches from the bottom to be able to see it, and I could only see the bottom for maybe two feet in either direction. My wife was with me swimming above and to my left and if I turned to look at her I could only see her mask and hand holding her console, but I could reach out and touch her. She said she never saw the bottom. She was not happy with the conditions at all. I found the whole thing somewhat unsettling at first then just marveled at how miserable it was. The interesting thing is there is a fairly significant tidal current here. There is a salt marsh at the head of the harbor that empties completely at low water. The tide had been running out for a couple hours when we started, and there was a definate temperature drop about the time you swam through the first layer. The current at the bottom is much weaker than at the surface. My theory on this is the warmer water from the harbor and marsh was running out over the top of the colder water from the bay, and the sediment layer at about 8' was at that boundry. What I cant explain is the suspended particles at the bottom. I have been in this harbor all spring, but have not run accross this. I would say I should dive it before the tide changes, but will that eliminate the crap at the bottom? It was very windy here last sunday, but has been pretty typical since and there has been no rain. I am looking for explanations that may make my diving more effectice and suggestions on how your supposed to find anything in conditions like that. Other than dumb luck I guess.

Sorry about the typos its getting late, but I wanted to throw this out while it was fresh in my head...
 
That's interesting... I really do not like low vis. It's not fun :( but of course if it's my only option i'm in!
 
I learned how to dive in extremely low vis....I don't particularly love it, but it's great experience to have. It REALLY forced me to have top notch compass skills, and virtually eliminated any sort of navigation related anxiety I might have had in good visibility situations. It's not as "fun," but it's good to know what that's like.
 
Welcome to my world.

Well, that's not exactly true. There are days when vis in our local Texas lakes reaches 10-15 feet, but there are others when you're doing good to see your console. Those are the days that make us appreciate the ones with "good" vis, and they REALLY make us appreciate our ocean dives.

I just finished viewing the finished product (on TV) that included video I shot for a local news station. They were doing a piece on the local police dive team, which almost always dives in near black-out condidions. Understandably, the video was a challenge to shoot, but it all came out good in the report...and it was a lot of fun to be a part of the project, too.

It gets better with more experience, by the way. Hang in there.
 
The absolute worst dive I've ever done was in our local lake. The viz was like you describe -- particulates in the water, blending into the actual bottom. My universe was limited by the lead weight on the end of the shot line my instructor was towing, and on the other side, the left side of my buddy's body. Nothing more. I didn't like it at ALL, and was very proud of myself for maintaining my composure until my buddies decided we weren't going to find the airplane, and ought to go up.

I dive low viz all the time (10 feet) but that was horrible.
 
10 feet or so of vis is not uncommon in this harbor. I have never seen it this bad though. I figure it has to do with the tide stage, but was wondering if anybody and seen this in a tidal environment.
 

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