My "breather" finally got out for a dive this month. After a couple of false starts earlier in the month, I packed the scrubber, checked the battery voltages, lubricated the o-rings and reassembled the Inspo (Australian slang for the Inspiration rebreather) ready for a freshwater dive in Lake Taupo on Sunday 10th April.
During the positive pressure test after assembly, there was a loss of pressure in the rebreathers loop. With the aid of soapy water, the leaks were quickly found and resolved (a small leak in the exhale hose connection to the counterlung tee-piece and from the dump valve.) The unit now held both its positive and negative tests. The auto diluent valve (ADV), manual inflators and Auto Air all worked without any problems.
Nigel Lees drove Dave Maddox and myself across to Lake Taupo via the Forgotten World Highway. After almost three hours of snaking through tight turns and unsealed sections of road and we were standing at the side of the lake in a small settlement called Pukawa. Our three Inspirations were unloaded quickly from the vehicle and the side slung tanks (for open circuit bailout off the rebreather loop) were placed at the waters edge for putting on in the water. After calibrating the rebreathers to account for altitude (Lake Taupo being at a height of 356m above sea level) and ambient air pressure, we pulled on our drysuits, strapped on the VR3 dive computers, and donned the Inspirations for pre-breathing the scrubber.
Pre-breathing the InspoAs always, a small group of onlookers watched as we approached the water and proceeded to ask the usual set of questions. Nigel took the role of spokesman for the day and answered with a knowing tone which seemed to appease the onlookers curiosity. I was getting too hot in the drysuit and walking about with the 32kg rebreather didn’t help, so I made a beeline for the water and geared up. Nigel and Dave pulled on their fins and side-slung tanks in the water. Dave had a 40cu.ft. aluminium tank, Nigel was using a 7litre Faber steel tank and I had a 10litre Faber steel tank (with an extra connector allowing it to be used as an off-board diluent source via the ADV.)
We all submerged and met up at the edge of a ledge in 3m of water. Here we checked for any bubbles (a sign of a leak in the unit) and adjusted the gear for comfort. Dave set off down the steep slope with Nigel and myself following behind. The water was 18C and the visibility dropped to about 8m after 18m of descent. Setpoints now at 1.3bar and using a modified frog-kick, we pushed out deeper following the now gently sloping contour of the lakes’ banks to a depth of 38m (Lake Taupo can get to a depth of 160m in places and we were diving a spot that went to 85-90m.) A thermocline in the water at 27m made the temperature drop to 15C and it was very noticeable (I heard Dave let out a yelp as he passed through it!)
Nigel was photographing the cheeky freshwater lobsters. At only 3-4 inches long, they would try and take you on by jumping up and snapping their pincers at you. The lake bottom is composed of mud with a fine silt sitting on top. Great care with buoyancy and finning technique are required to prevent a silt out. After 35 minutes of bottom time we turned and followed the slope upwards, taking care to stop at our first required stop depth.
The steep slope had occasional large rocks embedded in it. These rocks seemed to be places where small fish and freshwater lobsters congregated (they looked like they were having committee meetings or something very similar.) Nigel and Dave pressed their masks up close to one such gathering, but nothing seemed overly bothered by their presence. Ah, the joys of no bubble diving!
It was time to play at 14m with Dave deploying a DSMB (Delayed Surface Marker Buoy) which was yellow and had the word "EMERGENCY" written down its length. This type of SMB is fired off when there is a problem on a dive and assistance is required! When he pulled it out and was about to inflate it, I grabbed his attention and asked if he really wanted use that particular SMB and not his orange one for doing deco on. Dave signalled back that all was well and the SMB shot off to the surface dragging the line out of his reel effortlessly.
With all our stops completed, we switched our setpoints to 0.7bar just before the 3m ledge and made our way up the shore. In water shallow enough to stand in we closed our mouthpieces and walked out of the water. Very quickly we were all reminded of how heavy the units are when not supported by the water.
A quick check on the dive computers showed a runtime of 77 minutes.
We got all the gear packed and loaded into Nigel’s vehicle and then we headed home with one stop for refreshments and a blueberry muffin.
Wednesday, December 14, 2016
Thursday, December 1, 2016
Diving, diving, and even more diving
Wow, it's been a hectic month with all the diving I've been doing since my last post - "Cabin fever".
The Great Barrier Island dive trip was fantastic. The rugged native bush covered island is located north of the Coromandel Peninsula in the Hauraki Gulf, and is probably one the best kept secrets in New Zealand with it’s beaches and hidden bays. The water temp was 15C and the visibility varied from a few metres to about 25m, depending on the dive site.
A dive I did on the trip was to Channel Rock, between the Great Barrier Island and the Coromandel Peninsula. This pinnacle of rock sits in the middle of nowhere and experiences strong tidal currents, as I found out whilst struggling to push up into shallower water from 50m and up. My dive buddy, Gary Palmer, was diving his twinset on air (he couldn't find a gas blender to make up a mix in time for the trip) and racked up about 40mins more deco than myself on the rebreather. A very enjoyable dive despite my leaking drysuit.
One of the next dive trips was to Tutukaka, a gateway to the diving paradise of the Poor Knights. Jacques Cousteau rated the Poor Knights as one of his top ten dive sites in the world, and I can fully understand why. The New Zealand government made it into a Marine Reserve in 1981, and as a result, the marine life has become without exception both diverse and abundant. The Eastern Australian Current (the same one mentioned in the kids movie ‘Nemo’) flows past the islands bringing in turtles, whales, and more recently, manta rays.
I did two days of diving in the Poor Knights and the rebreather worked well. On one of the dives, we discovered a large eagle ray lying on a white sand shelf at 20m. When I lay down beside it and stroked its wing, the ray looked at me with it’s large eye and continued to gently breathe the water surrounding us. This is why I personally love the Poor Knights, you always have the opportunity to get really close to the marine life as nothing appears to be bothered by the presence of divers (either on closed circuit or on open circuit).
The majority of my other dives have been off the Taranaki coast. The warmer than usual water has meant that lots of species of fish have remained for the winter season. Even our resident great whites are nearer to shore than usual, with one getting snagged up in a commercial fishing boats nets. Sadly, it died before it was able to be set free. We even had a leopard seal come ashore for a photo opportunity with the local newspaper.
But by far the best thing I saw in the last week or so was a Southern Wright whale and her newly born calf playing only 150m offshore in 20m of water. This was in our Ngamotu Marine Park off New Plymouth, which 100 years before was a regular calving ground for the whales. Then a few days later a pod of Orcas came through. I'm just so lucky to have all this on my doorstep!
The Great Barrier Island dive trip was fantastic. The rugged native bush covered island is located north of the Coromandel Peninsula in the Hauraki Gulf, and is probably one the best kept secrets in New Zealand with it’s beaches and hidden bays. The water temp was 15C and the visibility varied from a few metres to about 25m, depending on the dive site.
A dive I did on the trip was to Channel Rock, between the Great Barrier Island and the Coromandel Peninsula. This pinnacle of rock sits in the middle of nowhere and experiences strong tidal currents, as I found out whilst struggling to push up into shallower water from 50m and up. My dive buddy, Gary Palmer, was diving his twinset on air (he couldn't find a gas blender to make up a mix in time for the trip) and racked up about 40mins more deco than myself on the rebreather. A very enjoyable dive despite my leaking drysuit.
One of the next dive trips was to Tutukaka, a gateway to the diving paradise of the Poor Knights. Jacques Cousteau rated the Poor Knights as one of his top ten dive sites in the world, and I can fully understand why. The New Zealand government made it into a Marine Reserve in 1981, and as a result, the marine life has become without exception both diverse and abundant. The Eastern Australian Current (the same one mentioned in the kids movie ‘Nemo’) flows past the islands bringing in turtles, whales, and more recently, manta rays.
I did two days of diving in the Poor Knights and the rebreather worked well. On one of the dives, we discovered a large eagle ray lying on a white sand shelf at 20m. When I lay down beside it and stroked its wing, the ray looked at me with it’s large eye and continued to gently breathe the water surrounding us. This is why I personally love the Poor Knights, you always have the opportunity to get really close to the marine life as nothing appears to be bothered by the presence of divers (either on closed circuit or on open circuit).
The majority of my other dives have been off the Taranaki coast. The warmer than usual water has meant that lots of species of fish have remained for the winter season. Even our resident great whites are nearer to shore than usual, with one getting snagged up in a commercial fishing boats nets. Sadly, it died before it was able to be set free. We even had a leopard seal come ashore for a photo opportunity with the local newspaper.
But by far the best thing I saw in the last week or so was a Southern Wright whale and her newly born calf playing only 150m offshore in 20m of water. This was in our Ngamotu Marine Park off New Plymouth, which 100 years before was a regular calving ground for the whales. Then a few days later a pod of Orcas came through. I'm just so lucky to have all this on my doorstep!
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