We were back in Elk River cave on the weekend, once again searching for a way on and through the current final sump. Over the last year or so we’ve laid 250m of line into sump 7 over several push dives. To achieve those dives there have been 15 trips into the cave – to survey, photography, resupply and explore. As the end of the sump got further and further away the dive required larger and larger tanks. This means each push dive trip requires two or three resupply and stocking trips to carry tanks to the end. One of those was just a month ago, where we carried “normal” sized tanks into the cave. Normal-sized for regular side mounted cave diving in Mt Gambier that is, where you can back the car up to the stairs and stroll down to the water. When I consider the trip from the car to sump 7, 12L steels no longer look normal sized – they look massive.
The last trip on which we carried two 12Ls and one 7L didn’t involve diving at the end and was relatively efficient. This weekend just passed we took advantage of having all the tanks at the end and romped in with (almost) empty hands. The early sumps had been crystal clear and with my little compact Lumix I tried to capture a few shots on the way in. The Lumix can take acceptable caving shots under the right conditions, but underwater images really show why it’s worth lumping the dSLR around. At sump 5 Tim and I geared up. Tim took two 12Ls and I rigged up three 7L tanks. I was very happy to have my new LTZ harness from DiveRite. I used it to carry my 3L tanks on the way in very comfortably and without getting stuck in any of the dry restrictions. Once at the final sump 35lbs of lift meant I could be neutral in my wetsuit and three full steel tanks, rather than bouncing along the bottom.
Tim and I progressed through sumps 5 and 6 in clear water, and swam down through the inevitable silt out at the start of sump 7. The silt is created as the divers walk across from the end of sump 6 and is unavoidable. Once through the cloud and about 20m down the line into sump 7 it usually clears up. I was following Tim so wasn’t all that surprised that the vis stayed poor – bubbles hitting the ceiling and the tiniest motion near the walls are enough to cause a silt out in Elk River. As we swam into some larger passage I became less sure about the water clarity. And then we followed the line up into the first air bell and the top 2m of water were crystal clear. At this point I realised that the milky, cloudy water wasn’t being caused by us. The silt was evenly distributed through the water throughout the sump. It did make it difficult to see the way on and as I bumped my way along the line I wondered how much further we would get with exploration.
The first photo above is in fact not a photo, but a screen capture from the GoPro which was on my hand (thanks Bradley!). It shows Tim on the way in, reel stowed for travel, descending from the small patch of clear water and back into the murk. We progressed to the end of the line and I slowed in a couple of spots along the way to fix tie-offs and add a few more silt stakes. Unfortunately Tim had some difficulties with line management in challenging conditions, and after attempting to get the new reel and old line working together, we decided to turn for home. The length of the sump and the restrictions along the way make for a slow trip to the end. Even with the very large (or normal-sized, depending on your point of view) tanks there is limited time available to make progress. Small difficulties are enough to mean it’s time to turn for home and try again another day. So, we’re up for a few more resupply trips to get some more tanks into the cave and set ourselves up for another go.