Last weekend my husband and I dove on the Milwaukee Car Ferry in Lake Michigan. We have been on this wreck many many times and were diving nitrox. Since we were getting to the end of the Lake Michigan dive season we decided to go out in 4 foot waves. Before I went out I took oral scopalamine to prevent sea sickness and have taken this medication many time without a problem when diving in the Carib. I usually get narced at about 100 feet in cold water (45 degrees) and react by being a little nervous, breathe a little faster and be over cautious. This time I was at 110 feet, at the end of my dive, had about 1400 pounds of air and was following my husband back to line to begin our ascent. Viz was about 20-25 feet. This wreck is a tangled mess of steel and can be very confusing. Somehow I lost sight of him, this has never happened to me before. I just waited for him to come back but he couldn't find me. I was so disoriented, I was midship but thought I was on the stern. I knew the boat runs almost east to west, all the ascent lines are on port side, and there is a huge propeller on the back of the boat. I looked at my compass, facing south and wonder why I couldn't find the line or the propeller on the boat. I still had no sense or urgency. All of a sudden I realise I am into deco, have less then 800 pounds of air, and I'm not a deco diver. I had to ascend all by myself, in a current without a line from 110 feet. Fortunately I was so narced, I had no fear, and didn't panic, I was able to understand my computer once it went into deco and able to make the first deco stop without a problem, the second stop was at 10 feet for 10 minutes. I ran out of air after 7 minutes and had to go to the surface. My dive time was 58 minutes compared to the usual 35 minutes for this dive. My husband was in the boat waiting and had already called the coast guard and reported I was lost. He pulled me in the boat, changed my tank, and I went back into the water, went down the mooring line to 30 feet and stayed for 30 minutes and then went up to 15 feet for another 10 minutes. It wasn't until the scopalamine wore off that evening that I realized how serious this was. If I had not listened to other divers talk about deco diving, I would not of known what my computer was telling me to do. I learned a couple of very improtant lessons, bad things can happen to experienced divers, and scopolomine can kill you. A medication that is fine in warm water and at shallow depths can act very differently when the body is under stress because of cold water and narcosis.
First of all, thank you for this open-hearted account of your dive. Sometimes it's hard to put yourself "out there" on the internet because you know people like to get all puffed-up and macho about what you did wrong and how they never make mistakes and all that.... We learn the most from reading how real people deal with real problems and I think I speak for all of us when I say "thank you".
About your dive. A couple of things are readily apparent to me.
1) disorientation is common on wrecks. Even to the point of being expected. Navigation on wrecks is notoriously difficult and it sounds like a combination of conditions, depth and the condition of this particular wreck wasn't helping you. That's understandable.
However,
with a little more experience, navigating difficult wrecks can be somewhat simplified. If you don't know where you are you can always tie off a reel and just swim in what seems like a logical direction. If you swim a short distance and the wreck ends then you can go back and try the direction 180 opposite what you just swam. If that also ends after a short distance then you found out that you were swimming the breadth of the wreck. If not, you're swimming in the length. Just knowing which way the wreck "goes" helps a lot in regaining your bearings and finding the up-line again.
2) your reaction to your situation came a little on the late side but your handling was spot on. You made your ascent, you did whatever deco you could do and you waited as long as possible before surfacing. The fact taht you weren't injured has a lot to do with how you handled yourself once you knew you were in the ****.
However,
It obviously would have been wise to get that alarm bell a little earlier. You know that and I'm sure if you find yourself in a similar situation in the future you will. Once crucial piece of the puzzle is knowing how much air you need to make a clean ascent. Learning a bit more about gas management might be a good idea.
3) after you exited the water you got back in with your husband and re-did some of your deco. This might help and it might not. In any case, all's well taht end's well and it's clear that you have an understanding of deco theory if you did this.
however,
You missed 3 minutes of stops. In that same situation I *personally* wouldn't have gone back in the water to re-do 40 minutes of deco. I would have stayed onboard, breathed 100% oxygen and hydrated as much as possible. IWR (in water recompression) which is what you did, does have risks associated with it and in a marginal case like yours I"m not sure the benefits outweigh the risks. Next time, if there is a next time, consider the possibility of "treating" a few minutes of missed stops with O2.
4) I'm not a doctor but if you suspect the drug you took then it's a good idea to ask about it in the medical forum. I would be interested in hearing what the doctors think of it. Just using google it looks like the kind of drug that can make you feel dizzy and drowsy so not the kind of thing that you want to be jacked-up on when you're on a deep wreck..... I would advise you to post something about it in the medical forum too so we can see how your experience compares.
R..
