Cold water vintage diving and buoyancy.

[captain]

Before BC's, on dives with thick rubber I would wear an inflatable flotation vest ( now called a snorkle vest) and if I was heavy on the bottom blow a little air in it. Being they didn't have dump valves to vent on the way up I would vent it thought the oral inflation tube while still on the bottom before beginning the ascent.

 

[John C. Ratliff]

I remember when I was experimenting with different buoyancy control strategies making a dive in Clear Lake (Oregon Cascade Mountains), and getting to about 45 feet where I took off my weight belt totally and clamped it into the anchor line of the boat we had. That was a fantastic dive, without anything hanging on my body but the scuba and my leg knife. I was wearing a 1/4 inch White Stag wet suit (skin two sides) for that dive, and was perfectly neutral. Now, I'd probably still need a few pounds (more body weight=blubber), but it is a very valid way of compensating for loss of buoyancy of the wet suit.

SeaRat

 

[Paladin]

A horse collar does make things a bit easier. I have a Sea Elite that I now use. It's a good BC at a good price.

 

[halocline]

I remember when I was experimenting with different buoyancy control strategies making a dive in Clear Lake (Oregon Cascade Mountains), and getting to about 45 feet where I took off my weight belt totally and clamped it into the anchor line of the boat we had. That was a fantastic dive, without anything hanging on my body but the scuba and my leg knife. I was wearing a 1/4 inch White Stag wet suit (skin two sides) for that dive, and was perfectly neutral. Now, I'd probably still need a few pounds (more body weight=blubber), but it is a very valid way of compensating for loss of buoyancy of the wet suit.

SeaRat

I'd like to dive in Clear Lake someday, and my sister lives pretty close by in Sisters. It's pretty cold for a wetsuit, isn't it? Something like mid 40s?

 

[JamesBon92007]

What is the cut-off year for "vintage?" When I got certified in '69 we used horse collars or Mae Wests. They have an oral inflator and a pull-string CO2 cartridge. In response to the original question, I always dived with steel tanks and weighted myself so I would be a bit negative at whatever depth I intended to end up at. My wetsuit did not seem to compress much more with depth past around 35-40 feet, at least that's how I remember it. Since I was almost always taking pictures I preferred to be slightly negative. Heck, I just can't think of a time when it was a problem. If diving more than 40' I usually wore my Mae West but don't recall ever blowing any air into it. When aluminum tanks came out I found I needed to add more weight to my belt due to the positive buoyancy when they are getting empty. That didn't seem to be much of a problem with steel tanks and since the author of this thread is diving "vintage" then that excludes aluminum tanks. And let's not forget about the built-in buoyancy device--our lungs. If too negative I tend to not empty my lungs as much, and if too positive I tend to empty them more and don't fill 'em up all the way. I probably can't do a test with my old wetsuit until I lose about 12 pounds and take some pain pills. It was a struggle to get into then and now I'd probably have to take some nitro too. It is called a 1/4" Farmer John and I also wore a 1/4" hood and 1/4" booties. It is nylon on two sides, is a "rack" suit, and has a little orca on it. I have no idea what kind of neoprene it's made of. I often was in water below 55 degrees and most of the shock occurred when I first got in the water. After my face began to move again I was relatively comfortable. Not cozy warm, but OK. I tried a hooded vest at one point but it was of no real help. I'm thinking a tight-fitting 1/8" (3 mm) shorty suit under the full suit might help but then you need to add about 5-6 pounds of lead. Probably not worth it. Best to just keep moving and find something fascinating to keep your mind off the cold

 

[John C. Ratliff]

I'd like to dive in Clear Lake someday, and my sister lives pretty close by in Sisters. It's pretty cold for a wetsuit, isn't it? Something like mid 40s?

Yes, the water temperature is approximately 37 degrees F when it comes out of the springs in the upper portion of Clear Lake, which is where the best diving is located. I have used wet suits in this water, but you need a "cold water" version of the wet suit. This involves using a vest (or hooded vest), and a well-fitted wet suit. Even then, it gives about an hour of comfort before you need to get out.

SeaRat

 

[USdiver1]

This past weekend, I was doing vintage diving in 40 degree (at 65 feet) H2O. I wore a 5mm Farmer John suit with beavertail jacket and hood. I weighed myself neutral at the surface with full tanks. I was probably 5 - 7 lbs negative at around 60 feet due to neoprene compression, but as long as I kept swimming, it wasn't noticeable. By the dive's end, I was neutral at depth. I was diving w/o a BC and with twin 72 steel cylinders and a double hose regulator. For me, proper trim is key, more so than being a couple of pounds negative or positive. As long as I can maintain that horizontal position with the dh regulator, all is well. Positioning of the cylinder(s) along your back is key, and twin tanks are much better than singles. An ideal set up depending on your size could be twin 38s, twin 50s twin 72s or twin 95s.