Backblog - Wreck diving trip

pjf on 2007-03-25T08:10:09

Wreck Diving Trip
The second part of our trip was spent wreck diving. The dives were performed at a more relaxed pace than the first trip, with 2-3 dives per day, albeit to much greater depths. With the exception of the Yongala, I've never done a wreck dive before.

Our first dive was on the M.V. Karma, a gravel trawler that took on water while being towed and sunk, only a few years ago. It's upright, in beautiful condition with the crane and structure fully intact, and in 25 metres of water.

Our second dive was on the Althea II, which is in 40m of water. This was probably the least enjoyable dive of the trip; we're only qualified to dive to 30m, so we could only really visit the very top of the rigging. As a deeper dive, I spent more time checking on my depth and time. Since there was a current, I also spent more time checking on my air consumption. We also performed the dive as a group of three, with one of the dive-masters from the boat, so I spent more time checking on my buddies. With all these checks, and a small touch of nitrogen narcosis, I didn't really spend any time looking at the wreck!

Our return to the boat was also complicated; Jacinta usually swims laps around me, and our dive-master (DM) had completed literally thousands of dives, so I assumed that I was the weakest swimmer in the group. However to my surprise our DM wasn't as strong a swimmer, and was loaded down with camera equipment, and had difficulty making her way back to the boat against the current. We ended up ascending as two groups, which is Not Good, although no other harm was done. Fundamentally this was a communication error, both in explaining capabilities before the dive, and communicating difficulties during the dive.

Our third dive was on the Barjon, a little fishing vessel that caught fire and sunk a few years ago. This had all the signs of a recent wreck, including a fire extinguisher, life-jacket, and pair of over-alls in the wreckage. It was also home to the most singularly photographed fish of our trip. It looked like a stonefish (a rare enough find to begin with, as they're extremely well camouflaged), but had what could only be described as legs which it used to crawl through the sand. It was almost as if a decorator crab had stuck a stonefish on its back.

After hitting the books back on deck, we discovered it was a Caledonian Stinger (Inimicus caledonicus), and certainly one of the oddest fish any of us had seen.

The next day we dived the Cochrane Artificial Reef in Hervey Bay. This is essentially an adventure playground for divers, with ships, planes, and other impressive wrecks in just 18 metres of water, and trails of concerete blocks between each structure. Armed with a compass and a map scribbled down on our slate, we first visited two aircraft (one small, and one quite large) on our first dive, and found some very friendly toadfish. On the second dive we visited two huge light ships (think portable light-houses), where the schools of silver batfish were so thick one had to push them aside to see the structure.

In the evening we dived the Snake Pit, an artificial reef that was an "exploratory dive", since none of us (including our skipper) really knew what was down there. It ended up being one of the greatest dives on the trip, with an astounding amount of life packed into a tiny little reef. We were greeted by a Flagtail Flathead at the bottom of the anchor chain, and a sleeping Bull Ray that was bigger than me! A little investigating revealed giant parrot-fish, a moray eel, some big toadfish, numerous wobbegongs and nurse sharks, and the occasional juvenile bull shark out in the darkness. The feature-point of the dive was finding a Sponge Crab with a huge sponge stuck to its back.

For our last day of diving we went to Wolf Rock, which could well be our best dive ever. Water of 26'C, no current, no swell, sunshine, and 25+ metre visbility. After a short period orienting ourselves with the dive site, we saw our first Grey Nurse Shark, which are famous for living near the rock. These are awe-inspiring creatures, and pose no threat to humans, and unfortunately their numbers have been dwindling. I thought that seeing a grey nurse was amazing by itself, but it wasn't long until we saw a school of Eagle Rays swimming in formation. I departed from the rock to swim alongside them for a while, with the rays barely moving to accomodate me.

After returning to the rock, it soon became apparent that we wouldn't just see a single grey nurse, but many of them. At one time I counted five swimming as a group, and turned to discover two more behind me. I'm certain there were other things to see on the dive, but it was hard to take my eyes off the sharks. I feel that some of them were almost as curious as we were, as they would commonly swim alongside us, a fantastic opportunities for photos.

One of the most memorable points of the dive was when Jacinta, myself, and a grey nurse were trying to navigate the channel that lies in the centre of the rock. Before the dive we were briefed in protocols to observe while the sharks were present. Give them space, and do not swim above them, as this makes the sharks grumpy. Unfortunately with all three of us in the channel, our were not able to give the shark enough space to pass, and we discovered first-hand what happens when a grey nurse gets grumpy.

Despite normally appearing quite placid, the grey nurse is able to move its tail so quickly it can create a sonic boom underwater. This is very loud, and very penetrating, and when the shark is just a few metres away one can really feel it pound through one's torso. I imagine it's a defense mechanism designed to stun any nearby creature, and it certainly stunned me! The shark also moved with incredible speed away from us, and I felt very relieved that a grumpy grey nurse is not aggressive to humans.

After our safety stop, which was performed on the rock with grey nurse sharks and some wonderfully friendly and brightly coloured parrot fish, we discovered the surface conditions were just as calm as we had left them. We had a very plesant surface swim back to the vessel, where we were assured by the dive crew that these were the best conditions at Wolf Rock they had ever seen.

The afternoon's dive was on the remains HMAS Brisbane, a wreck specially placed and modified to be diving-friendly, including the opportunity for experienced divers to penetrate the wreck without specialist qualifications. Local regulations required that the first dive on the wreck be a guided tour, and so we performed the dive with a group of five other divers and a dive-master.

Unfortunately the wreck proved to be a disappointment. The visibility was poor, there wasn't much to see inside the wreck, and the tour was so fast and the group so large it was hard to do any exploring properly. Since we were required to stick together, we had to surface when one of the other divers started to run low on air, despite Jacinta and myself having plenty of air and no-deco time remaining. I feel that this would have been a much better dive without the group and tour.

The dive was also complicated by us being ferried to the site by the ship's tender, which meant hauling weight-belts and gear over the side and scrabbling in, rather than a more peaceful climb of a diving platform. In the confusion Jacinta's cutting-shears were lost, probably our least expensive piece of diving equipment, but very bothersome to lose nonetheless.

The rest of the day was spent steaming back to shore, and the next day was spent in Brisbane were we explored the Roma Street Gardens while waiting for a long enough surface interval for us to fly. A few hours were also spent in an internet cafe, catching up on e-mail.

In the next few days ahead I get a whole day at home before flying to linux.conf.au for the week.