Wednesday, December 20, 2006

The Hesper wreck. At the limits!

On many dives along the house reef I spotted a wreck on the sand, at the bottom of the wall, usually 15m (~50 feet) below the lowest point of my deep dives. It was clearly a small boat. And it sat out of the range of the nitrox I was breathing. Clearly, to find out more about this nebulous shadow deep below me a bit of planning would be required.

A quick check with the dive masters and sure enough they knew the hull sits in roughly 40m or 132 feet of water. I mentioned the idea of exploring the wreck to Mike. He didn't dismiss it outright, and soon his interest grew too. After a couple of days we discussed the wreck over dinner and decided to go for it. Lotsa water, early to bed, and air instead of nitrox for our morning deep dive.

I had been to 40m twice before this. Both times with instructors, for training in conditions significantly worse than found here. So my training was up to par. And my curiosity was peaked. But my confidence was walking, not running, behind the rest.

Sure enough, something clicked in my mind as we passed 30m. By the time we were at 40m I was aware I was breathing twice as hard as normal. And since I was hovering over a sandy bottom, with no current there was no good reason for that. Perhaps "scariest" though, was not the mental thrill of the depth but was seeing my dive computer tell me I had 5 (FIVE!) minutes before I would be forced to decompress. Even at this depth I had 15 minutes or more of air. But only a fraction of that time before pushing things farther than desired.

In truth, we had known the time limits we would have before we went deep. We planned it and planned to leave once the computers showed 2 minutes left. And we did. On the way up we stopped often at intermediate depths, and ran out our air in shallow water for an extra long safety stop. Quite a safe and tame dive shared between two good dive buddies. But psychologically it was a real ride!

The fact that the Hesper is now just two pieces of hull, one standing and the other laying beside it, wasn't the least bit disappointing!

The whole time (all three minutes) on the wreck I swam in an unusual position. Instead of hands crossed under me, I held both arms out holding my gauges and computer directly infront of my face the whole time. (I noticed by the end Mike was too.) I was certainly paranoid and wanted to know if it was the depth or nitrogen narcosis.

Nitrogen narcosis is common in most divers (mildly) by 30m and a serious issue by 50m deep with air. It is the narcotic effect of nitrogen under high pressure. Normally inert in metabolic and chemical processes in the body, at 4 ata of pressure and beyond nitrogen can be fun! It can make you feel euphoria, nicely drunk, or paranoid. It causes poor judgement and coordination. And of course it's dangerous and thus 40m is set as a limit for recreational diving.

And stepping back after going to the limit is a serious rush! It took no arm-twisting to get Mike to agree to repeating the dive the next day. But the second time on Nitrox, custom blended for the depth.

Chris took two half-empty 40% mixes we'd used the day before, ah custom nitrox, and with some magic fiddling made us two tanks of 26% nitrox filled to 3200psi each. That's a safety limit of 41m... 0.5m into the sand. And the result?

10 minutes of bottom time on both computers! Of which we used 8! We set a limit for "up" at 2000psi or 2 minutes (no decompression time) remaining. And at 2 minutes I had (relatively) tons of gas left.

Partly the nitrox, and partly the experience of the day before, my breathing seemed unaffected by the depth. And my brain was not at all paranoid. Was the narcosis gone? I still swam with my gauges a lot. But some times didn't and just enjoyed the wreck.

An old ladder still sits in the old fishing boat. It looks like you could take it up to the surface and still use it. Except for some old rope, the floor of the boat is indistinguishable from the sand plateau around it. Little critters in shells seem oblivious to the fact that they're living in a boat.

The wreck will continue to disolve into the ocean faster than most corals will grow on it. Someday it will be barely visible as debris in the sand. Like trying to imagine a rose by seeing peddles scattered on the ground. There are so many details to explore you could stare all day.

Could and should are different things. At that point, I could have stayed longer. But knew I shouldn't. Mike and I made a relatively long dive again. Visiting the much shallower La Muchaca wreck higher up the reef, and taking longer than required for safety stops.

How did doing these dives help me? Simple! The next day I visited the Hilma Hooker and was amazed by how well I remained calm *inside* the wreck. Later the same day I spent longer on a dive with a single tank of air than ever before! These "training" dives made all the difference in the world to my comfort in later dives. And they've helped my confidence catch up to my training. A nice feeling!


Minka said...

Fore a minute I was like: Calm down , Minka...he is writign thsi post after all!

I never went diving and teh wya you describe it makes me wanna try. Sadly, I live in a plac ethat is almost unsuitable for diving practices...but during teh next holiday abroad, I´ll put this on my list to do :)

Glad you remained clam too and be careful out there!

Mike said...

Nitrogen Narcosis - its legal intoxication below sea level! Nothing to be afraid of - do you give your regulator to a fish when you are drinking at the pub? So why would you do it underwater?
Or put another way - If you see someone in the pub handing their regulator to a fish - never dive with them below 30m ;)

IDiveAtNight said...

Mike, they're working you too hard. Come home, relax, have a beer. Put down the mouse and step back from the teleconference.

Minka, Iceland has some beautiful dive sites. Although divers who visit them are considered crazy by some (more boring) divers, I think they're cool. (Pardon the pun.)

narcosis in paradise said...

Wow, great dive huh !!! Wish I did that one with you guys, but theres always next year. I already have the 2 weeks booked..and now I can't wait to get there. Morgan, give Mike my e-mail address...Please.... Hope you're doing well....Kisses W

Mike, your buddy for the dive said...

I don't remember having any qualms about diving that wreck, in fact the two times we dived it makes it around 5 or 6 times I've dived it! As you may remember there are some good photo opportunities! The good vis certainly makes a change from the English Chanel at those depths. Did you like the Garden Eels on the bottom? Maybe we can do thwe wreck a few times next year. If you are up for it we can drop down to the 40m mark on one of the boat dives. Have fun, Mike