09 Dec - Engine Trouble!
RRS Ernest Shackleton Diary
Position at 1200 (UTC - 3 hours): 68°21'S 014°32'W (Approximately 90NM east of Saunders Island)
Next destination: Halley
ETA: Approx. December 16 2001 (but never certain due to ice conditions)
Distance to go: 479 NM (if a direct route is taken, however the figure is unknown, again due to ice conditions)
Total Distance Sailed this Season: 10742.8NM
Wind: SW x Force 6
Barometric pressure: 980.9 mb
Sea state: Up to 9/10ths pack ice
Air temperature: -1.5°C.
Sea temperature: -1.7°C.
Vessel making steady progress, working around floes....
Ships position taken from the regular weather observations (only available whilst at sea, courtesy of Oceanweather.com). Select "South Atlantic" area and click on "Marine Observations". Callsign is ZDLS1.
The beginning of this week has been a very hectic time for the engineers onboard. On Sunday there were signs that the port main engine was not working correctly and following investigations all the symptoms showed that there was a problem with one of the cylinders. A water leak was spotted and this indicated that all was not well with No 6 cylinder and so a full strip down of this cylinder would be required to determine the problem.
Once the cylinder head was removed a crack in the liner could be seen, which was causing cooling water to go where it shouldn't. The Ernest Shackleton carries a vast array of spares for the machinery onboard and there were two new liners in the stores. Work continued throughout the week to get the engine back to normal operation as soon as possible. When working in pack-ice, which we would before the end of the week, all the power available would be required to help us make way, and also help us get out of any sticky situations. Following some late nights to get it all back together, the engine was run up again in the early hours of Wednesday morning and back in full operation by Wednesday lunchtime. The picture here shows the Chief Engineer, Peter Brigden, with his head in the engine whilst 4th Engineer Tom Balfe stands by with his favourite spanner. Click on the image to enlarge.
Late Tuesday night the science transects were completed and the vessel headed for the next science starting point, at 60° S 010° W, where we would then turn due south. By Wednesday morning we had encountered our first pack ice and were skirting around it until the port main engine was back online and by the early evening the ship had started to work through the pack.
Wednesday morning also saw a very good sighting of a pod of killer whales, only a few hundred metres off from the ship. This pod was made up of both adult and juvenile whales and were visible for ten minutes or so. Killer whales tend to travel in small groups, or pods, and normally contain one dominant adult male, several breeding females plus juveniles of both sexes. They are curious animals and will often approach a vessel. At about the same time the first Antarctic petrel was also sighted. This bird is similar to the cape petrel but is larger and without the spattered white paint effect on the wings. They are not normally seen in the vicinity of ships, unless fishing is being carried out. Wednesday afternoon saw the start of our next set of science work, this being the launching of XBT (expendable bathythermographs) probes.
By Thursday lunchtime the ship had reached position 60°S 010°W and so turned to the south. The first sighting of a leopard seal was made, with her pup, on an ice floe. The name is given due to the spotted coat of the animal and it has a snake-like head, one that looks dangerous. The pack ice was proving to be no great problem at this stage, as the vessel picked its way from one patch of open water to the next. At this stage we are still to the north of the Antarctic Circle and so it does still get dark for a few hours each day. With darkness comes the problem of spotting the larger lumps of ice, growlers and bergy-bits, and so a special high-powered searchlight is used. This has been used every night since we sailed from South Georgia, and also on the way there too, and is an invaluable aid to the safe navigation of the ship.
On Friday morning the first emperor penguin was spotted, at about 62°S 010°W. This was a juvenile, as it did not yet have the distinctive colours of the adults. Several more were spotted on ice-floes, as well as some more leopard seals and Adélie penguins. Also, this was the first bright and sunny day for some time, which was much appreciated by all those onboard.
Saturday evening, at 2135 UTC the Ernest Shackleton crossed the Antarctic Circle in position 66°30'S 012°03'W. This was just before the grand event of the week took place in the Red Room bar, being the Horse Racing Evening, attended by some of the finest people onboard. Proceeds from the event will be given to the RNLI upon the ship's return in May next year. Along with a cocktail party held last week, somewhere in the region of £260 has been raised. Thanks go to those involved in making both evenings a great success.
Further sightings of seals, including a single Ross seal, penguins and whales (latterly minke whales) have been spotted over the weekend. As I write this on Sunday afternoon, a minke whale has surfaced just ahead of the ship, and a second time alongside the bow, only a few metres off. A very spectacular sight - alas that there is never the time to photograph.
The watchkeeping onboard has changed now that we are working in the ice. The four Deck Officers, Captain, Chief Officer, 2nd Officer and 3rd Officer are now doing twelve hour watches and there are always two on watch at any one time. This allows for one to work from the Conning Tower whilst the other remains on the Bridge. The Conning Tower, with its extra height, does help give a better view of which way to possibly go.
On the international front, the German vessel Polarstern was in position 63°58'S 004°26'E bound for their Neumayer Station, hoping to arrive on Tuesday December 11. They are also awaiting some Dornier aircraft, but these were still stuck in Punta Arenas waiting on improved weather before they could fly via Rothera and Halley.
The South African vessel S.A. Agulhas was due to have sailed on Friday afternoon for SANAE, but contact has not yet been made with them, although it is hoped to be able to talk with them soon.
Weddell Polynya Study with the Deployment of XBT's, by Trevor McCormack
In the mid-seventies the now well known Weddell Polynya, an area the size of the UK, remained ice free for three successive winters. It has been postulated that open ocean convection plays an important part in the formation of Antarctic Bottom Water (AABW), which was produced in enormous quantities during the presence of the polynya over two decades ago. AABW production is one of the principal components of the global thermohaline circulation. So its production in the Weddell Sea is of particular relevance to the circulation in the Atlantic Ocean.
Knowledge of the conditions that trigger the polynya event is of particular interest to enable us to understand the processes that lead up to the polynya's reoccurrence. In order to determine the interannual variability in conditions in the area of the Weddell Sea where the polynya occurred, RRS Ernest Shackleton has been deploying expendable bathythermographs (XBT's) during the Southward leg of the first call to Halley along 10°W from 60°S to the coast depending on ice conditions. This is the third year of such a study.
From early afternoon on Wednesday the first XBT probe was launched and probes have been deployed every 3-6 hours since. An XBT probe is launched off the aft deck with the ship slowed to 5-6 knots or slower if the sea ice is likely to interfere with deployment. The probe falls through the water column taking temperature readings as it does so. There are two varieties of probe available, one that collects data to 700 metres and another to 1580 metres. The data from these are acquired in real time on a PC in the laboratory, and later sent to BAS HQ in Cambridge and the Hydrographic Office, who provide the probes, for analysis and interpretation.
Forthcoming events: Continue towards Halley Base.
The next update will be written on Sunday December 16 and should be published on Monday December 17.