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Navigation Skills and Mild Hypothermia
WTXDIVER - 8/08/2008 10:20 PM
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Category: Educational
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My daughter and I went diving at Lea Lake in Bottomless Lakes State Park near Roswell New Mexico last weekend. We both added Dry suit certs last winter since the only diving we have access to are lakes with cold bottoms and well lake diving visibility. Lea Lake is a spring fed sink hole with a max depth of 110 ft adjusted for altitude. The springs flows at about 3 to 4 thousand gallons per min. In the summer the surface temp can be in the upper 70’s Visibility is best in the winter.

This dive weekend we found the best visibility near the springs which is normal but in general the visibility as my 16 yo daughter said sucked. 15- 20 ft. near the spring dropping very quickly moving away to 5-10 ft. The first thermo-cline was a about 12 ft and roughly every 15 ft after that below 65 ft was 48 f however we were both reasonably comfy in our new Whites Fusion dry suits and thermals with hoods and gloves.

On our second dive of the day we set four markers using safety sausages and reels for navigation practice. Setting the markers went well. We both took compass readings, depth readings, counted kick strokes, and time between markers and recorded them on dive slates as we went. As I said this went very well and we both were confident we could re navigate the dive the next day. 

On day 2 we went back to the lake to retrace the navigation steps between the markers. The first dive went well. In order widen our visible sphere we spread out so we could still see each other easily and still cover the widest posible search path. Dropping to the bottom at the first marker we retraced the dive taking only 28 min to to find the other three makers.

Our second dive we were going to rework the navigation process in reverse adding also to the problem solving issues by maintaining a constant depth of 40-45 ft which placed us totally in a visual sphere of brn/grn water with no fixed references.

That should have been enough to throw things off quite easily, I however felt very confident with the result of the morning dive and elected to only wear my thermal jacket and no hood, after all the morning dive only took a 1/2 hour bottom time.

Starting the dive by dropping to 45 ft and establishing neutral I reeled in the sausage and Rachel stowed it and the reel on her BC then we checked our dive slates and compasses and set out on our first leg. Very quickly I realized I was having difficulty maintaining a constant compass heading but could quickly make corrections Rachel seemed to me to be doing fairly well. We did find the second marker but the time at depth from marker 4 to marker 3 was 12 min almost 1/2 of the mornings total dive. Somewhere between maker 3 and marker 2 I found myself on a compass bearing 70 degrees from were it should have been and Rachel tugging at my sleeve signalling me to surface with her. After surfacing she told me I had gone more the 60 kick strokes past what we had recorded on the wrong bearing and she was totally lost.

The truth is Rachel was not lost at all she was following a dive buddy who was lost and suffering from mild hypothermia and unable to process the mental problem solving required for this dive.

Later that night after returning home I wrote in my log book how foolish and overconfident I had been. I knew the water was cold, I knew the problem I had set up would be significantly harder than the mornings problem and ignored these things and ther significance

After almost 30 years of diving I can still learn things from my 16 yo daughter. Stay warm, stay safe, stay alive.

Thank you Rachel

Love Dad