We've just returned from a successful Cocklebiddy Cave expedition. Cocklebiddy Cave is the longest underwater cave in Australia, with a huge water-filled tunnel travelling 6km from the entrance. It's interrupted only by 2 dry rockpiles which require divers to get out of the water and lump all their gear to the next lake. In order to repeatedly dive the end of the cave, we planned to camp in the second rockpile chamber for 5 days. This meant in addition to the normal amounts of bailout, backup scooters, lights and batteries, we also needed to take food, drinking water (the cave is brackish) and camping gear.
In 2016 when we did several set up trips and then a day trip to the second chamber, each diver scootered with 4+ large tanks and a spare scooter hanging off them. This time around Steve invented a sled which was towed by one diver and tended by the second. That left me free to take both photos and video - check us out in action below!
The key to our successful camping trip was scooter power. We each had a lower power/capacity scooter for the 3000 feet / 1km of sump 1. For sump 2 it was time to get out the big guns, with the sled towing alternating between a P2 and an older Cuda with a new lithium battery inside. While towing we ran the scooters on cruise speed as we needed to preserve battery for the 2.4km dive to the second rockpile.
Both scooters had no problems towing the sled which had 26 large bailout tanks, 16 caving bags of gear and drinking water, 4 dry tubes and an old Classic wing for variable buoyancy on top of the fixed buoyancy tubes in the centre of the sled. The travelling caravan weighed approximately 2,000 pounds out of the water, or just under a metric tonne, but floated like a ballerina once the buoyancy was correct. Watching it moving smoothly through the massive tunnel as we powered into the cave was amazing.
In one direction we used approximately 70% of the juice from Ryan's P2, with a total dive time of just over 3 hours. My P2 which covered the same distance with a camera and lights on board and two scooters on tow had used about 40% of the battery. We recharged both P2s from the stage batteries inside the dry chamber, and five days later they did an equally spectacular job of towing the same sled out of sump 2 in 2.5 hours.
In our five days underground we each completed multiple dives into the third sump. Steve added approximately 100 feet of line to the known end of the cave, Ryan added about three times that into various side leads, and I took over a thousand photos. The trip required 8 scooters between three divers, including piranhas, cudas and a sierra. The power of the piranhas and the reliability of the whole DiveX fleet made the long run with a tonne of gear through Cocklebiddy Cave's spectacular tunnels a very enjoyable experience.