Tuesday, October 12, 2010

Dive 165 - Hide And Seek in the Dark

Just back from Diving Union Lake tonight in a non-typical night time dive.

Because Keith and Mills had the last dive of their Overhead class set for today Chad and I were to tag along, but turn our lights off once they entered the simulated overhead so they could do a lost diver search. James cunningly placed a glow stick and our lights would have interfered with their search for it so into the darkness we went.

It started out pretty cool - following their lights and it was pretty clear they didn't know where we were. Of course we soon got our of range of their lights and entered what was pretty much total darkness at 30 feet.

One issue with total darkness in the water is your start to lose your reference points and since you're starting off weightless you can lose where your position is in the water pretty easily. Which of course, I did.

Moving along to keep up with the field of light cast by their lights, I would occasionally lose them completely, enter total darkness and swim along. Then on just a couple occasions I would feel a soft sensation enveloping me as I hit the silty bottom - that was rather embarrassing, but it told me where I was. Getting off the bottom, I would continue on, heading toward their lights if I saw them.

On the way back, we saw some nice sized Bass lying on the bottom, and since our lights were off they didn't even bother moving as we passed them.

So it was a good dive, if a bit muddy at times. Very instructive in terms of no light night diving and plenty to work on as usual.


Scott said...

Don't they have some sort of artificial horizon like they have in aircraft that could help you with the dark orientation thing? A little display in the corner of your mask or something?

Wouldn't help you if you lost the mask, I guess, but perhaps enough to keep you from unexpectedly contacting a less friendly bottom than you had last night?

Aaron said...

There is the Oceanic Datamask with an integrated heads-up display that gives you info like amount of pressure remaining in your tank, depth, dedcompression calcs and such but its very expensive and not really necessary if you can do some basic math in your head. It doesn't seem to have a compass either.

Positioning in the water isn't to bad except for hitting the bottom when you can't see it - bubbles always go up so you can tell your atitude if you can see them.