Cold water diving
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Thanks! I much prefer to keep it simple.
I didn't realize that ice water would be right at 32. Mistakenly thought it might be a degree higher.
I think I'll recalibrate my analog gauges on my spg's right now, just for fun, in anticipation of getting into some nice clear icewater this winter to tweak my insulation.
The low end was 1 degree off last time I checked.
Dave C
Just a bit of correction. It's at 39F/4C which water have the highest density. Other than that, the rest is very accurate
When ice diving in lakes one will "always" find temps around 39F at the bottom, and colder further up underneath the ice. In our fiords there's an interesting phenomena as the water can be VERY cold on the surface. Perhaps 34-35F. With surface temps like these I've personally experienced 8C/46F at 30m/90ft in the Oslofiord! This is because salt water is even denser, and with no wind cold freshwater from rivers float out on the surface of the fiord like a carpet, not mixing with the warmer sea.
Very interesting!
In those conditions, I'll bet you're also able to see a very distinct blurry layer where the saline and fresh waters meet.
Now, you've given me a good excuse for some ice diving this winter: to document that 39F layer on the bottom of ice covered lakes. That's an interesting fact.
It's always nice to have a real goal on an ice dives! Too often, the guys want to get the dive over with pretty quickly and not really explore or experiment. Or the tender gets cold and slowly shortens my "leash". A goal might keep 'em more motivated!
Dave C
DOkie
Guest
I have never seen 39 degrees at the bottom of a frozen lake!!! That would be nice!!! Last winter, 14 of us went on one of the usual weekend ice dives. 6 of us had a temp on both computer and analog of 31 degrees. 4 had 28 degrees. 3 had 29-30 and one had 32. Are you going to tell me that only one diver had the correctly callibrated dive gear??? All of the above divers went to different depths and this was their coldest temps. Only "pure" water freezes at 32 degrees. I doubt that any of us have this kind of freshwater in our lakes or streams (minerals, traces of chemicals, fertilizer run offs). The motion of water also affects it's freezing temperature. (Underwater springs, rivers, etc.). Sediment can also effect freezing. So it is actually possible to have an accurate reading of 30 degrees....
Now that I actually think about it, 39 degrees would be nice at the bottom of the lake in the middle of July!!!!
Now that I actually think about it, 39 degrees would be nice at the bottom of the lake in the middle of July!!!!
KOMPRESSOR
Contributor
I'm sorry, but I have no idea what you're talking about. Yes, freshwater freeze at 32F and (almost) ONLY then. You need to put A LOT of salt in it to make it perform otherwise. Your temp gauges are all off, which shouldn't surprise you. They're not exactly spot on instruments, and very often it takes a while for them to stabilize.
There's no way it can be LESS THAN 32 degrees at he bottom of a (freshwater) lake when you're diving. Then you'd look like something out of Ice Age 2, the movie! In a solid block of ice... Seriously, if you believe what you are saying and they let you out of school, you'll have one heck of a lawsuit against your school! You're gonna get rich man!
I don't know why not all of you just KNOW THIS for a fact??! Water is at its heaviest at 4C = 39F
If you go deep enough you'll find 39F, or 4C as I prefer to say. Perhaps learning Celsius would have made this idea easier to grasp for you, I don't know. But ordinary scuba depths is usually enough to find 39F when ice diving. I know this because I learned it in school. It's common knowledge around here. And for the sake of it I've had the chance to check it out many times.
DOkie
Guest
Exactly who the hell do you think you are insulting me like that? I was NOT insulting anyone else on this board. First of all, since you have never dove it and seen it does not mean that it's not possible. Maybe the United States Department of energy would be able to clear this up for you. I'm NOT saying water does not freeze at 32 degrees. I am simply stating that PURE WATER freezes at 32 degrees. Factor in what I stated before and you have a different temperature.
Telling me if I go deep enough? How the hell do you know how deep I've been? HUH??? Maybe you should actually dive and not spend so much time in SCHOOL. The Great Lakes are considered a Freshwater lake. Or don't they teach that in your school??? Water temps in the summer get below 39 degrees at depth depending on location. That fact can be verified by the State of Michigan.
Now where'd I leave that chestnut??? Gotta go diving....
Telling me if I go deep enough? How the hell do you know how deep I've been? HUH??? Maybe you should actually dive and not spend so much time in SCHOOL. The Great Lakes are considered a Freshwater lake. Or don't they teach that in your school??? Water temps in the summer get below 39 degrees at depth depending on location. That fact can be verified by the State of Michigan.
Now where'd I leave that chestnut??? Gotta go diving....
mobster75
Contributor
hmmm... on second thought...
JRScuba
Contributor
How cold it is really depends on you and your environment. I came to SE Florida as it was to cold in New Jersey.
Dove last week in SE Florida and the water was cold. 75 degrees.
That was in a wetsuit, not a toasty warm drysuit.
Dove last week in SE Florida and the water was cold. 75 degrees.
That was in a wetsuit, not a toasty warm drysuit.
KOMPRESSOR
Contributor
You clearly state that you have measured 28-30 degrees Fahrenheit while diving in freshwater. You may have a right to an opinion, but it's a fact that IT WASN'T 28-30F in the water. So be offended if you want to when I say that you are wrong, but you clearly missed out on something in 4th grade if you keep saying you were swimming in 30F freshwater. Google it or look it up elsewhere. This isn't politics were you can say whatever suits you.
You may have temps from 32F in the water underneath the ice, gradually rising to 39F as you get deeper. You may or MAY NOT come close to 39F at diving depths, but most places were a lake is temperate in the summer, only the upper levels of the water body cools to below 39F. As it does this the water shifts until the whole body of water reaches 39F. Then the shifting halts, and the water starts cooling of at the top, and ice may form.
The Great Lakes may be a cool place to dive, summer and winter. But unless it's a very shallow lake (I don't think so...), it will be 39F at the bottom in the deeper parts of it. Now it may be less at depths you are diving, but as you're gauges has shown 28-30F it's more likely that they do not show the correct temps.
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