Posted by Ross-O on May 02, 2005 at 13:35:13:
I had an interesting gear failure on Saturday.
Four of us dove a wreck in about 140’ this weekend. We dove in teams of two. My buddy and I planned 20 mins at 135FSW and 20 mins of deco on 50% O2. We were diving doubles & dry. The dive was great fun and deco was uneventful. As I typically do, I swam back from the anchor line to the swim step underneath the boat to check for any obvious problems. On the way I went back to my long hose and stowed the hose on my 40cf bottle of 50% so I would look good as I surfaced. I was at 5FSW and almost back to my sterndrive when out of nowhere came this excruciatingly loud PONG noise. It was like someone placed a steel plate near the side of my head and hit it with a hammer. After I got done flinching and cursing in my reg, I tried to figure out what the hell just happened. My first thought was that a burst disk ruptured but I didn’t hear and didn’t feel any bubbles. My second thought was maybe my SONAR transducer somehow did something to me as I was only a few feet below it. It makes a completely different sound when I touch it so I was really stretching here but something had to make that noise! When I got to the swim step, I found that part of it had broken from the first team. Could that have made the loud noise? I didn’t think so, but I was pretty much of out of ideas so I just accepted it as the culprit and moved on.
The mystery was solved on the way home. About 15 mins into our boat ride back home we all heard a loud POP and then a pretty good air leak. Some searching turned up air rushing out of a rupture near the 1st stage of my long hose. I later found another slit in the outer casing near the 2nd stage. My latest theory is that a pinhole leak formed in the inner core of the hose pressurizing the sheath or outer layer. The first loud pop was the sheath rupturing. The flow rate of the leak was so small that it didn’t make a significant bubble stream. The second pop was the inner core letting go. The rush of air popped the sheath in several locations and made all the hissing noise.
I had all the right stuff with me, including doubles, a good plan, and great dive buddy so it wouldn’t have been a big deal had it happened 19.5 mins in the dive. I can see how this would get really exciting for those single tank solo deco divers out there.
Ross-O