03 Feb - Offloading Cargo
RRS Ernest Shackleton Diary
Position at 1200 (UTC - 3 hours): 72°58'S 019°33'W
Next destination: Halley
Distance to go: 200NM by Twin Otter
Total Distance Sailed this Season: 15802.3NM
Current weather: Overcast with good visibility and contrast
Wind: S x Force 3
Barometric pressure: 986.5 mb
Sea state: 10/10th Pack Ice, short leads and small pools.
Air temperature: -8.3°C.
Sea temperature: -1.8°C.
Current, frequent weather observations reported back to BAS Headquarters in Cambridge is used to plot the ship's current position and recent track. Meteorological data are also available from this page. The callsign of RRS Ernest Shackleton is ZDLS1.
On the morning of Monday January 28 the Ernest Shackleton broke through the pack ice and entered the shore lead. The shore lead is a band of open water that is between the ice shelf and the pack, and this can vary in width from tens of metres to tens of miles. The ship followed the lead towards Halley, but by 0900UTC on Wednesday it had closed up in the vicinity of the Stancomb Wills Glacier. Just prior to the end of the lead, two large groups (in excess of 20 animals) of killer whales swam ahead of us for some time. These were family groups, consisting of adults and juvenile whales.
The Stancomb Wills Glacier has always been a bottleneck for pack ice, as the head of the glacier protrudes out into the Weddell Sea and catches all the pack that is drifting past, moving with the wind and the current. Due to the predominant wind of recent weeks, all the pack has been pushed in towards the glacier.
The vessel attempted to make progress through this pack, but after many hours of forcing a passage, backtracking and trying a different route it became apparent that there was nowhere for us to go. Several more hours were then spent on getting back out into the shore lead. The picture here shows a view of the pack ice in the vicinity of Stancomb Wills Glacier as seen from the Bridge.
Once back in the shore lead the ship was put into a large floe for the night. At about this time a Twin Otter aircraft, which was based at Halley, flew across to do a recce on the ice around the Stancomb Wills Glacier. The information from the pilot was not good, but much as expected. The view from the air was much as we had seen, with even greater consolidation of the pack further around the glacier. The pack started some three kilometres from the N9 relief site and this would then mean that there was some 60 miles of pack between the shore leads at either end of the glacier.
Following some discussion between the base and the ship, the decision was then made to head back up the shore lead, to the east, to an area used by the German personnel from Neumayer as a summer field station, called Drescher Inlet. This area has a good ramp to the shelf ice and the intention was to run cargo up to the shelf and then fly it across to the base. However, when we arrived in the early hours of Thursday morning, it was apparent that the sea ice was fairly extensive and that the journey via the ramp to the shelf would be a long one. A number of personnel were put onto the sea ice to check it out and it was decided that it would be good enough to land the aircraft on, which then meant that they could taxi close to the ship, making the cargo operations that much easier and quicker.
An airstrip (known as a skiway) was marked out, being nearly a thousand metres in length and running in a direction of 030°/210°, which was the best direction for the prevailing winds. Initially the skiway was marked out using bamboo poles with black bin liners attached, but this was then modified to bin liners filled with snow and later empty black oil drums.
By 1030 ships time the first aircraft had arrived and was being loaded with fresh and frozen provisions for the base, something that was being eagerly awaited at Halley. Also transferred to the base were the new wintering personnel, some of whom have been onboard the ship since October!
The images above show the Twin Otter aircraft on the sea ice adjacent to RRS Ernest Shackleton. Click on the images to for a larger version.
The de Havilland Twin Otter aircraft is a high wing, twin engine, turbo prop aircraft capable of carrying up to twenty passengers in the commuter role. The aircraft has a wing span of 65 ft (19.8 m), length of 51 ft 9 in (15.7 m) and a maximum take-off weight of 12,500 lbs. (5670 kg). The Twin Otter is one of the de Havilland family of "bush" aircraft noted for their rugged construction and Short Take Off and Landing (STOL) performance.
The flying time from the base to the ship was about one hour and ten minutes, with the return flight taking slightly longer at about one and a half hours. Allowing for the fuel carried and the distance to the base, the aircraft are able to carry approximately 1000 kgs of cargo per flight.
Thursday saw nine flights to and from the ship. Several times there were two aircraft alongside the vessel and so it was a busy time for all. For the flights on Thursday the aircraft were refueling at the base, but when Fridays flights commenced this changed and the aircraft started to fuel whilst alongside the ship as we were carrying base fuel supplies.
Initially some of the food was transported to the aircraft by a chain gang, as we were short on sledges, but later in the day more sledges arrived and so now the cargo is lifted off the ship onto the sea ice, then placed onto sledges and towed, either by hand or by skidoo, to the loading point for the aircraft some sixty metres away. Due to a change in the weather only seven flights took place on Friday and with poor flying conditions there was no flying on Saturday.
Sunday has started out as a beautfiul day with some bright sunshine and good conditions for the aircraft and so the rotations have started once again. One thing that has to be done before a flight either arrives or departs, is to check for emperor penguins straying across the runway. There is a large penguin colony about 10kms away and we have had a number of them down to the ship to visit. The problem is they do not think to look for the aircraft, and so a sweep of the runway is made prior to aircraft movements and if there are any birds in the way they are gently moved on to safer areas. There have also been a number of emperor chicks visit us in the past few days, along with one lone adélie who popped ashore for a few minutes to check on our intentions.
The images above show some Emperor chicks inspectin the ship and a close up view of an emperor chick, still with his down cover. Click on the images to enlarge them.
Evening recreational activities have included rugby and football on the ice, along with some kite flying - and all this at about minus 9°C .....not my idea of fun!!
All eyes are currently on the long range weather forecast and it is hoped that on Wednesday there is going to be a change in the wind direction, and possibly even a storm! If this is the case it may well open up the shore lead around the Stancomb Wills Glacier and allow us access to the N9 relief site, and a full discharge of cargo can then commence. During the time down here the temperatures have been very low, with the daytime in the region of minus 9°C and down as low as minus 14°C. The shore lead has in places started to freeze, with grease and pancake ice forming as shown in this image.
Forthcoming events: Continue to Halley relief site as and when conditions allow.