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16 Dec - Ice Trouble!

RRS Ernest Shackleton Diary


Position at 1200 (UTC - 3 hours): 71°46'S  026°48'W
Next destination: Halley
ETA: Unknown at this time
Distance to go: 232.3 NM (if a direct route is taken, however the figure is unknown, again due to ice conditions)
Total Distance Sailed this Season: 11094.4NM

Current weather: Overcast with snow flurries
Wind: W x Force 4
Barometric pressure: 967.9 mb
Sea state: Up to 10/10ths pack ice
Air temperature: 0.0°C.
Sea temperature: -1.7°C.


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.


This week has seen a change in the ice conditions with the vessel encountering heavy pack ice and vast floes (Please see below for ice terminology). Navigation was carried out from the Conning Tower as it is possible to see further with the added height. Often a complex course, sometimes seemingly in the wrong direction, would need to be taken in order to avoid coming to a standstill and all in all progress is slow.

The Deck Officers are continually looking for leads in the ice (areas of open water) and at times the ship was 'puddle hopping' from one area of open water to another.

View from the Bridge taken on 12th December 2001  This picture, taken on December 12, shows the extent of the pack ice. Below this ice there is some 5000m of water!


This week has not been one for covering vast distances. The distance steamed since the last update has only been 351.6 nm, which would normally only be about 36 hours steaming if in open water. Last Sunday, December 9, saw Pack coverage 8/10th, 1st year ice, vast and big floes, medium thickness, strips of water between floes. By Monday the Pack was 9/10ths, 1st year, big and vast floes, medium/heavy thickness, pressure around floe edges, lack of water and the vessel was stopped.

Tuesday and Wednesday of this week saw the vessel stopped, waiting for a frontal weather system to pass by and hope that this would ease the pack and allow further progress. Thursday morning and a fire exercise was held, based in the Foc'sle, and once this was completed an attempt was made to continue towards Halley.

Steady but slow progress was made for the remainder of Thursday and on Friday at 1645UTC the vessel was stopped in big floe, 71°36S, 026°34W, awaiting a change in ice and weather conditions. Since then there has not been any further attempts to make progress, due to the closeness of the pack and the prevailing winds.

It should be noted, however, that although the vessel is stopped in a big floe, it has been drifting - and in the right direction too.

At present all that can be done is await an improvement in the ice conditions, which will only come with a change in the weather, and then we should be able to continue on our way.

Whilst progress has been hampered, much has been happening onboard. During the week there has be abseiling down the Bridge-front and then practicing recovering from crevasse falls.

Saturday night was the time for a treasure hunt and a mulled wine evening. The was preceded by an amazing dinner with food from around the world superbly cooked by the Galley team and FID catering staff.


Due to the somewhat lack of events, whilst stopped, I thought that a bit of history on the Weddell Sea would not go amiss, as it is in the Weddell pack that we are currently sitting:

The Weddell Sea is named after James Weddell, Master, RN, who commanded the sailing brigJane of Greenock, on three privately organised voyages to the Antarctic at a time when he was on naval half-pay, following the end of the Napolionic wars. There is no detailed record of his first voyage, to the South Shetland Islands in 1819 -1821 and this proved to be a financial failure. Weddell then bought a share in Jane and accompanied by the cutter Beaufoy (under the command of Captain Michael McLeod), made his second voyage in 1821 - 1822. Both ships visited South Georgia and the South Sandwich Islands. In December 1821, McLeod made a search for new sealing grounds eastwards from Elephant Island and independently discovered the South Orkney Islands only six days later than George Powell (onboard Dove) and Nathaniel B Palmer (onboard James Monroe). These new islands were then visited by Weddell in February 1822.

On his third voyage of 1822 - 1824, once again in company with Beaufoy (under the command of Captain Matthew Brisbane), Weddell made surveys in the South Shetland Islands, South Orkney Islands before sailing in search of new land. In unusually open ice conditions he reached position 74°15'S 034°16' W in the sea that was later named after him.

Weddell was alone among the early British sealers in leaving a record of his explorations in book form, published in 1825.

The first venture in Jane was financed by John Strachan, a merchant of Edinburgh and Leith. His second and third voyages were joint ventures of James Mitchell, who was a London merchant, Strachan and Weddell himself, and were equal failures commercially. Strachan wrote in 1843 ' In consequence of Captain Wedell devoting so great a proportion of his time....to the purpose of investigation and discovery, he neglected the legitimate object of his undertaking (which was ... the procuring of seal skins) so much, that the result .... was most disastrous to all concerned, and ended in the total ruin and bankruptcy of the daring navigator.'


Ice Terminology:

Iceberg - A massive piece of ice of greatly varying shape, protruding more than 5m above sea-level, which has broken away from a glacier, and which may be afloat or aground. Icebergs may be described as tabular, dome-shaped, sloping, pinnacled, weathered or glacier bergs.

Bergy bit - A large piece of floating glacier ice, generally showing less than 5m above sea-level but more than 1m and normally about 100-300m² in area.

Floe - Any relatively flat piece of sea ice 20m or more across. Floes are subdivided according to horizontal extent as follows:
Giant: Over 10 km across
Vast: 2-10 km across
Big: 500 - 2000m across
Medium: 100 - 500m across
Small: 20 -100m across

Floeberg - A massive piece of sea ice composed of a hummock or a group of hummocks, frozen together and separated from any ice surroundings. It may typically protrude up to 5m above sea level.

Fast ice - Sea ice which forms and remains fast along the coast, where it is attached to the shore, to an ice wall, to an ice front, between shoals or grounded icebergs. Vertical fluctuations may be observed during changes of sea level. Fast ice may be formed in situ from sea water or by freezing of floating ice of any age to the shore, and it may extend a few metres or several hundred kilometres from the coast. Fast ice may be more than one year old and may then be prefixed with the appropriate age category (old, second-year or multi-year).

First year ice - Sea ice of not more than one winter's growth, developing from young ice; thickness 20cm - 2m.

Growler - Smaller piece of ice than a bergy bit or floeberg, often transparent but appearing green or almost black in colour, extending less than 1m above the sea surface and normally occupying an area of about 20m².

Hummock - A hillock of broken ice which has been forced upwards by pressure. May be fresh or weathered. The submerged volume of ice under the hummock, forced downwards by pressure, is termed a bummock.

Ice blink - A whitish glare on low clouds above an accumulation of distant ice.

Ice edge - The demarcation at any given time between the open sea and sea ice of any kind, whether fast or drifting.

Ice shelf - A floating ice sheet of considerable thickness showing 2-50m or more above sea level, attached to the coast. Usually of great horizontal extent and with a level of gently undulating surface. Nourished by annual snow accumulation and often also by the seaward extension of land glaciers. Limited areas may be aground. The seaward edge is termed an ice front.

Lead - Any fracture or passageway through sea ice which is navigable by surface vessels.

Pancake ice - Predominantly circular pieces of ice from 30cm - 3m in diameter, and up to about 10cm in thickness, with raised rims due to the pieces striking against one another.

Polyna - Any non-linear shaped opening enclosed in ice. Polynas may contain brash ice and/or be covered with new ice or young ice.

Sastrugi - Sharp irregular ridges formed on a snow surface by wind erosion and deposition. On drift ice the ridges are parallel to the direction of the prevailing wind at the time they were formed.

Sea ice - Any form of ice found at sea which has originated from the freezing of sea water.

Tabular berg -A flat-topped iceberg. Most tabular bergs form by calving from an ice shelf and show horizontal banding.

Water sky - Dark streaks on the underside of low clouds, indicating the presence of water features in the vicinity of sea ice. A helpful indication when working in sea ice as to which direction to take.


Forthcoming events: Continue towards Halley.


Due to the forthcoming Christmas and New Year break, the next update of the Ernest Shackleton's progress will not be until January 3 2002.

On behalf of Captain Marshall, his Officers, Crew and all onboard RRS Ernest Shackleton, a Merry Christmas and Happy New Year to all our readers.

Mike Gloistein
ETO(Comms)