Ice pier
Encyclopedia
Intermodal container
An intermodal container is a standardized reusable steel box used for the safe, efficient and secure storage and movement of materials and products within a global containerized intermodal freight transport system...
. Operation Deep Freeze
Operation Deep Freeze
Operation Deep Freeze is the codename for a series of United States missions to Antarctica, beginning with "Operation Deep Freeze I" in 1955–56, followed by "Operation Deep Freeze II", "Operation Deep Freeze III", and so on...
personnel constructed the first floating ice pier at Antarctica’s southernmost sea port at McMurdo Station
McMurdo Station
McMurdo Station is a U.S. Antarctic research center located on the southern tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program, a branch of the National...
in 1973. Ice piers have been in use each summer
Summer
Summer is the warmest of the four temperate seasons, between spring and autumn. At the summer solstice, the days are longest and the nights are shortest, with day-length decreasing as the season progresses after the solstice...
season since, at McMurdo’s natural harbor
Harbor
A harbor or harbour , or haven, is a place where ships, boats, and barges can seek shelter from stormy weather, or else are stored for future use. Harbors can be natural or artificial...
at Winter Quarters Bay
Winter Quarters Bay
Winter Quarters Bay is a small cove of McMurdo Sound, Antarctica, located 2,200 miles due south of New Zealand at 77°50'S. The harbor is the southern-most port in the Southern Ocean and features a floating ice pier for summer cargo operations. The bay is approximately 250m wide and long, with a...
located at 77°50′S 166°40′E. The harbor is positioned on the southern tip of Ross Island
Ross Island
Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound.-Geography:...
.
Historically, two supply ships, a freighter
Cargo ship
A cargo ship or freighter is any sort of ship or vessel that carries cargo, goods, and materials from one port to another. Thousands of cargo carriers ply the world's seas and oceans each year; they handle the bulk of international trade...
and a tanker
Tanker (ship)
A tanker is a ship designed to transport liquids in bulk. Major types of tankship include the oil tanker, the chemical tanker, and the liquefied natural gas carrier.-Background:...
, arrive at the ice pier each summer, after an icebreaker
Icebreaker
An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters. Although the term usually refers to ice-breaking ships, it may also refer to smaller vessels .For a ship to be considered an icebreaker, it requires three traits most...
opens a ship channel through pack ice. The ice pier’s key function is to provide a platform for freight trucks to come alongside a supply ship to receive or offload cargo. Steel cables attached to shoreline hold the dock
Dock
-In transportation:*Dock , a structure for handling ships**Drydock, a basin that can be flooded and drained to allow a load to come to rest on a dry platform**Ferry slip, a docking facility that receives a ferryboat...
in a fixed position.
Port officials distribute freight arriving at the dock to McMurdo Station
McMurdo Station
McMurdo Station is a U.S. Antarctic research center located on the southern tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program, a branch of the National...
, nearby Scott Base
Scott Base
Scott Base is a research facility located in Antarctica and is operated by New Zealand. It was named after Captain Robert Falcon Scott, Royal Navy, leader of two British expeditions to the Ross Sea area of Antarctica...
, and to field camps as far away as the South Pole
South Pole
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth and lies on the opposite side of the Earth from the North Pole...
. Imports include virtually any materials needed to support personnel living and working in Antarctica. Exports range from items such as scientific ice core samples and human waste collected from field camps to broken equipment and recyclables for return to the United States for processing.
Ice piers typically have a lifespan of three to five years. Once an ice pier is no longer usable, icebreakers tow the pier to sea to be cast adrift.
Annual break-in opens ship channel
Icebreaker
An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters. Although the term usually refers to ice-breaking ships, it may also refer to smaller vessels .For a ship to be considered an icebreaker, it requires three traits most...
s opening a ship channel from Upper McMurdo Sound
McMurdo Sound
The ice-clogged waters of Antarctica's McMurdo Sound extend about 55 km long and wide. The sound opens into the Ross Sea to the north. The Royal Society Range rises from sea level to 13,205 feet on the western shoreline. The nearby McMurdo Ice Shelf scribes McMurdo Sound's southern boundary...
to Winter Quarters Bay
Winter Quarters Bay
Winter Quarters Bay is a small cove of McMurdo Sound, Antarctica, located 2,200 miles due south of New Zealand at 77°50'S. The harbor is the southern-most port in the Southern Ocean and features a floating ice pier for summer cargo operations. The bay is approximately 250m wide and long, with a...
. One or more icebreakers, depending upon seasonal conditions, will typically open a channel from eight to 50 miles (80.5 km) long.
However, in 2005 icebreakers encountered more than 90 miles (144.8 km) of pack ice blocking entry to McMurdo Sound
McMurdo Sound
The ice-clogged waters of Antarctica's McMurdo Sound extend about 55 km long and wide. The sound opens into the Ross Sea to the north. The Royal Society Range rises from sea level to 13,205 feet on the western shoreline. The nearby McMurdo Ice Shelf scribes McMurdo Sound's southern boundary...
. The ice buildup occurred when a 100-mile-long iceberg (B15A) ran aground near Upper McMurdo Sound. Two icebreakers eventually broke a ship channel through to Winter Quarters Bay.
The ship channel provides a seaway for the few annual re-supply vessels and research ships which call upon the extraordinarily remote seaport at McMurdo Station. Preparation for the supply ships’ arrival includes icebreakers maintaining a uniform edge on the seaward side of the pier. The ship’s skipper maneuvers the icebreaker to use its bow as a giant battering ram to scarf or shave jagged edges from the pier to facilitate ships tying up at the dock.
Ice pier expedites shipping
U.S. ships discharged cargo at temporary iceportIceport
An iceport is a a more-or-less permanent indentation in the front of an ice shelf, that can serve as a natural ice harbor. Though useful, they are not always reliable, as calving of surrounding ice shelves can render an iceport temporarily unstable and unusable.-Historical and present use of...
s in McMurdo Sound
McMurdo Sound
The ice-clogged waters of Antarctica's McMurdo Sound extend about 55 km long and wide. The sound opens into the Ross Sea to the north. The Royal Society Range rises from sea level to 13,205 feet on the western shoreline. The nearby McMurdo Ice Shelf scribes McMurdo Sound's southern boundary...
prior to the military’s invention of the ice pier. Ships during that time moored alongside seasonal pack ice where military longshoremen offloaded cargo onto large snow sleds. Equipment operators then used snow cats and tractors to tow the freight over ice to McMurdo, a difficult and potentially dangerous operation. Tankers
Tanker (ship)
A tanker is a ship designed to transport liquids in bulk. Major types of tankship include the oil tanker, the chemical tanker, and the liquefied natural gas carrier.-Background:...
arriving with oil, diesel fuel, and gasoline were forced to dock as far away as ten miles (16 km) from the harbour and pump their fuel ashore.
Beginning in 1964, icebreakers started opening a ship channel to Winter Quarters Bay where ships tied off to fast ice, a form of sea ice
Sea ice
Sea ice is largely formed from seawater that freezes. Because the oceans consist of saltwater, this occurs below the freezing point of pure water, at about -1.8 °C ....
attached to the coast or ice wall such as Antarctica’s Ross Ice Shelf
Ross Ice Shelf
The Ross Ice Shelf is the largest ice shelf of Antarctica . It is several hundred metres thick. The nearly vertical ice front to the open sea is more than 600 km long, and between 15 and 50 metres high above the water surface...
. However, mooring to fast ice produced undesirable results. Warm water discharged from ships eroded ice at the rate of some three square kilometres every year.
Consequently, port authorities built a steel dock in 1972, which waves from a storm destroyed soon after. Builders came up with an alternative that same season. They constructed a block of ice, covered it with matting and straw and used it as a fender for a tanker that docked at the harbor in fall 1973. The ice fender became the forerunner to the contemporary ice pier.
McMurdo's dock is not without comparison. In 1987 workers constructed a similar pier in Mys Shmidta, a small seaport located in Chukotka, a far-eastern territory adjacent to Alaska on the Arctic Sea. And, like McMurdo, the Arctic ice pier facilitated getting ships to get closer to shore for loading cargo. The pier built in the former Soviet Union measured more than 700 metres long.
Seawater construction
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Subsequently, workers construct a snow berm to a depth of several feet along the perimeter of the soon-to-be ice pier. High-volume pumps then flood the pack ice with seawater to a depth of about 10 cm (4 in). The seawater typically freezes solid within 24 hours. Personnel repeat the flooding until they achieve a thickness of 1.5 m (5 ft).
Next a reinforcement mat of approximately 2,100 m (6,900 ft) of 1” (25mm) steel cable is secured to 2” (50mm) steel pipe embedded in the ice pier. The pier overall requires approximately 6,300 m (21,000 ft) of steel cable for construction, according to National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
permit documentation.
Workers repeat the entire process three more times until the ice pier is approximately 6.7 m (22 ft) thick. Wooden utility poles drilled about four deep into the final ice pier support electrical and telephone service to the pier. Moreover, during the final construction phase, personnel mount shorter poles in the ice edge to serve as bollard
Bollard
A bollard is a short vertical post. Originally it meant a post used on a ship or a quay, principally for mooring. The word now also describes a variety of structures to control or direct road traffic, such as posts arranged in a line to obstruct the passage of motor vehicles...
s to secure the pier to the shore at McMurdo. A 15–20 cm (6–8 in) layer of volcanic gravel tops off the pier to provide a non-slip surface and to insulate the ice from the summer sun.
Experience has shown that ice piers have a lifespan of three to five years. Factors such as stress cracking and erosion shorten the duration. In addition, storm surges, wave action, contact with vessels, and the warm water discharge from ships contribute to degradation of the pier’s seaward edge.
Ice pier limits discovered
Conditions worsened the following week when additional storms pushed ice, slush, and sea water onto the pier, flooding about one-half of the dock. The inundation on the pier's seaward side reached three to six-feet high and froze nearly immediately, according to the NSF report. The strategy to repair the storm damage included adding additional restraining cables followed by routine flooding to build up the ice thickness.
Notable incidents with damaged ice piers at McMurdo Station include an event 10 years earlier. The ice pier had been in use four seasons in 1983 when the freighter USNS Southern Cross docked at Winter Quarters Bay. Operation Deep Freeze
Operation Deep Freeze
Operation Deep Freeze is the codename for a series of United States missions to Antarctica, beginning with "Operation Deep Freeze I" in 1955–56, followed by "Operation Deep Freeze II", "Operation Deep Freeze III", and so on...
officials pressed the pier into extended service in order for the freighter to make an unprecedented two supply runs in one season from Port Lyttelton, New Zealand, to McMurdo. However, efforts to extend the ice pier’s lifespan resulted in a cargo truck breaking through the ice. The driver of the truck standing atop the container leapt to safety, receiving minor injuries.
Maintenance gives way to disposal
Maintenance on the ice pier begins at the end of the austral summer. Equipment operators remove the gravel and store it for the next season. Removing the gravel prevents the gravel’s insulating qualities from inhibiting further thickening of the ice during winter. Winter operations include plowing insulating snow from the dock and flooding the pier with seawater to help sustain the ice strength.However, when the pier is no longer usable, a permit from the Antarctic Conservation Act allows for an icebreaker to tow the ice pier out to McMurdo Sound and cast it adrift. Preparations for dumping include:
- Pumice surface is removed
- Wooden poles are cut off just above the surface of the ice
- All equipment, materials, and debris are removed
After release at sea, currents and southerly winds drive the ice pier north towards the Ross Sea
Ross Sea
The Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
and into the circumpolar currents of the Southern Ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
. A beacon mounted on the pier allows for tracking and serves as a warning to ships. The pier mixes with pack ice and eventually melts, a process that can take years, according to NSF estimates. Consequently, some 21000 feet (6,400.8 m) of 1 inches (25.4 mm) steel cable and 650 feet (198.1 m) of 2 inches (50.8 mm) pipe used in its construction sink to the ocean floor
U.S. government reports vary regarding the fate of the untreated wooden bollards used in the ice pier. The wood in some instances is reported as weighted so as to sink. Yet a 1999 ocean dumping permit notes that: "the short lengths of wooden poles will float in the ocean for several months before becoming waterlogged and eventually sinking to the ocean floor."
See also
- IcebreakerIcebreakerAn icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters. Although the term usually refers to ice-breaking ships, it may also refer to smaller vessels .For a ship to be considered an icebreaker, it requires three traits most...
- IceportIceportAn iceport is a a more-or-less permanent indentation in the front of an ice shelf, that can serve as a natural ice harbor. Though useful, they are not always reliable, as calving of surrounding ice shelves can render an iceport temporarily unstable and unusable.-Historical and present use of...
- Ice RoadIce roadIce roads are frozen, human-made structures on the surface of bays, rivers, lakes, or seas in the far north. They link dry land, frozen waterways, portages and winter roads, and are usually remade each winter. Ice roads allow temporary transport to areas with no permanent road access...
- McMurdo SoundMcMurdo SoundThe ice-clogged waters of Antarctica's McMurdo Sound extend about 55 km long and wide. The sound opens into the Ross Sea to the north. The Royal Society Range rises from sea level to 13,205 feet on the western shoreline. The nearby McMurdo Ice Shelf scribes McMurdo Sound's southern boundary...
- McMurdo StationMcMurdo StationMcMurdo Station is a U.S. Antarctic research center located on the southern tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program, a branch of the National...
- Operation Deep FreezeOperation Deep FreezeOperation Deep Freeze is the codename for a series of United States missions to Antarctica, beginning with "Operation Deep Freeze I" in 1955–56, followed by "Operation Deep Freeze II", "Operation Deep Freeze III", and so on...
- Sea iceSea iceSea ice is largely formed from seawater that freezes. Because the oceans consist of saltwater, this occurs below the freezing point of pure water, at about -1.8 °C ....
- Scott BaseScott BaseScott Base is a research facility located in Antarctica and is operated by New Zealand. It was named after Captain Robert Falcon Scott, Royal Navy, leader of two British expeditions to the Ross Sea area of Antarctica...
- Winter Quarters BayWinter Quarters BayWinter Quarters Bay is a small cove of McMurdo Sound, Antarctica, located 2,200 miles due south of New Zealand at 77°50'S. The harbor is the southern-most port in the Southern Ocean and features a floating ice pier for summer cargo operations. The bay is approximately 250m wide and long, with a...