Our Elk River supply trips are now down to a fine art. Each push trip requires two or three resupply trips – removing the empty tanks from the previous exploration, taking in full tanks, plus caching other gear as required. We are now using a lot of carbon fibres tanks for the longest swim through sump 7. The carbon fibres are much, much lighter than equivalent steel or aluminium tanks and can hold higher pressures.
The drawback of the carbon fibre tanks is their buoyancy characteristics in the water.We have placed kilos of lead weights at the diving gear up spot. Each 9L tank takes 6kgs of lead to sink it. We are definitely not carrying this lead backwards and forwards. But there are four small sumps on the way home that the carbon fibre tanks need to pass through.
My preferred technique for passing sumps with a very buoyant caving pack is to descend and get myself under the lip of the rock ceiling. From there, flipping upsidedown and bracing against the ceiling allows for a good tug on the caving pack. With the pack safely wedged under the lip it’s a matter of doing the upsidedown spider crawl across the roof.
On the far side of the sump the pack will rocket to the surface as soon as it is free of the roof. The accompanying diver can then surface, remove mask, clip the pack tether and keep on trucking down the cave.
These photos were taken on our way in last Saturday. The water clarity was remarkably good and I was able to get some underwater shots on the small camera. The manual settings on the Lumix allow for a fixed shutter speed of 1/25 and with an ISO of 800 this is enough for the Scurions to light up the picture. It may not have the quality of the dSLR, but the Lumix is a lot easier to transport through the cave!