January 13, 1999

Brian Kakuk and Paul Heinerth exited the decompression chamber at 1:30 a.m. today after yesterday's dive. Here they're on the two hour bends watch after their decompression was over. Brian, especially, was a happy camper. He's been unable to dive due to a persistent cold for several weeks, so he was really pleased for a good dive into A Tunnel. Their dive was approximately 1400 meters (4600 ft) down A Tunnel from the Grand Canyon (a large room not too far inside the cave that lies underneath the Wakulla Springs Lodge). The mapper data looks good, too [photo ©1999 Tom Johnson].

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A Tunnel Mapping Mission 1/12/99

By Brian Kakuk

After ten days of being land-bound, I was excited by the fact that I would finally be getting back into the spring for a mapping run with my good friend Paul Heinerth. Paul would be driving the mapper while I ran ahead scouting out waypoint buoys and pointing them out for Paul to fly over. I was also excited at the fact that I would finally be working in an area of the cave where the conditions are much more representative of where we will be working for the rest of the expedition.

Once our mapper guru Nigel Jones had briefed us on some finer points of collecting the data from the cave, we, and our support crew, were off and running. My array of equipment included: a MK5p rebreather, two primary lights, three backup lights, a primary reel for patching up vandalized permanent guidelines, two replacement radio beacon battery packs, two 80 cf off-board diluent cylinders of heliox 10/90, one 13 cf cylinder of argon for drysuit inflation, one Fatman primary scooter, one smaller Thinman back-up tow scooter, and the usual drysuit, mask, fins, etc. Paul's setup was the same with the exception of the self-propelled mapping unit, instead of a Fatman primary scooter.

Once Paul and I were underway, he parked the mapper in the download cradle at 8.5 meters (28 ft) in the spring basin. After aligning the mapper for our run and switching to our heliox, we motored into the cave. The conditions in the beginning of the cave were spectacular, with fantastic blue water, and the huge borehole passage that is Wakulla's signature.

We passed the D tunnel junction, then G tunnel, and a few minutes after that the cave took on a whole new feeling. We soon found ourselves enveloped in tannic river water, with very little reference other than the guideline and an occasional glance at a wall, ceiling or silty floor. I thought to myself, "this is what you will be dealing with from here on out, (probably worse) so get used to it." The feeling is much different than that of diving in low or no visibility caves of smaller size. Most of us have learned to "feel the cave" in the smaller passages we are accustomed to back home. This is something that just won't happen here at Wakulla.

Nevertheless, Paul and I continued on down the main passage to map the area that Matt and Mark had set up with radio beacons and marker buoys the day before. We arrived at the first radio beacon, which was in the center of the passage, a few hundred feet before the K tunnel junction. I disconnected the spent battery canister and clipped it off to my harness. I then picked up the perfectly neutrally buoyant radio beacon and scootered it to the next junction (the junction prior to the K Tunnel junction). While Paul dealt with positioning the beacon, I sped off to fix some loose line up ahead, near what Matt first called "the DCS dome" then dubbed "La Onda Grande" (the "Great Wave" in Spanish). This is a huge breakdown area covered in deep silt which rises from a depth of 85 meters (280 ft) to a floor depth of 52 meters (170 ft). According to the computers on our MK5p's we had a few minutes of decompression before being able to cross over the top of the huge breakdown pile. We quickly passed over the shallow area and continued on down the slope, returning to a "normal" depth and the next beacon.

The battery pack was removed from this beacon and the transmission coil was left in place for another mission to deal with. We motored past a WKPP cylinder cache a short distance away and then came to a junction in the line. A line arrow was placed on the junction and the right hand passage was chosen as we continued on into large passage for another 100-120 meters (300 to 400 ft). At this point Paul flew the scooter down to a small ledge in the wall to re-align the mapper for the flight home. The trip out was much faster, with me lighting up the waypoint buoys for Paul to fly over. We only stopped one time to turn on the beacon near the K Tunnel junction. The clear blue water near the G Tunnel junction was a welcome sight as we cruised through what is now familiar territory.

Upon reaching the entrance we signaled the fixed in-water camera that is at 55 meters (180 ft) to let the surface crew know that we were back safe and sound. A second and third camera are stationed on the bottom of the spring to alert the support divers of our impending ingress towards the bell at 24 meters (80 ft). The ingress to the bell and the gear recovery were flawless; thanks to our now well-trained support divers. Paul and I were in the bell, on deck and connected with the main chamber in no time at all.

Our deco was spent reading magazines in the warm 70-degree chamber, munching on double whoppers (with cheese) and listening to our chamber operator Tom Johnson tell very poor jokes on the comms box. At 1:30 a.m. Paul and I crawled out of the chamber tired but full and warm after a more than 11 hour run time (and it's only going to get longer after this).

Tom Johnson (left) has been a real trooper tending the chamber during late night decompression. Here he's monitoring the chamber oxygen sensor while his protege, Pete Mulholland (UK), performs a routine chamber vent. Returning divers go onto breathing masks at 21 meters (70 feet) depth, first with Nitrox 50/50 (50%nitrogen, 50% oxygen) and finally, to pure oxygen (at 10 m/30 ft). In order to reduce problems related with oxygen toxicity, the chamber is pressurized with compressed air (at 21% oxygen). However, despite having top of the line "bibs" (breathing masks with overboard exhaust valves), some of the oxygen-rich decompression gases seep from the mask, particularly when the divers are asleep. As the oxygen content rises, responsible tenders like Tom monitor this concentration and when it begins to creep over 25%, they vent the chamber with a flush of fresh air [photo ©1999 Barbara Anne am Ende].

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