Coast Guard Cutter Polar Star (WAGB-10), commissioned in 1976,was built by Lockheed Ship building and Construction Company of Seattle, Washington along with her sister ship USCGC Polar Sea (WAGB-11).These two icebreakers are the only polar icebreakers in the U.S.fleet. Both are homeported in Seattle, Washington. Polar Star and Polar Sea operate under the control of Pacific Area and coordinate their operations through the Ice Operations Section.
Polar Star is an outstanding Polar icebreaker with exceptional hull design, power, strength and weight. The design, which was the result of three years of research and testing, incorporates a number of innovative features that affect nearly every aspect of operations. Equipment on board is highly sophisticated. Polar Star uses four different methods of electronic navigation to overcome the difficulties of high-latitude operations, and a computerized propulsion control system to effectively manage six diesel-powered propulsion generators, three diesel-powered ship's service generators, three propulsion gas turbines, and other equipment vital to the smooth operation of the ship. The extensive use of automation and low maintenance materials have greatly reduced staffing requirements.
Polar Star's three shafts are turned by either a diesel-electricor gas turbine power plant. Each shaft is connected to a 16-foot(4.9-meter) diameter, four-bladed, controllable-pitch propeller. The diesel-electric plant can produce 18,000 shaft horsepower(13,425 kilowatts) and the gas turbine plant a total of 75,000 shaft horsepower (55,925 kilowatts).
Polar Star has sufficient hull strength to absorb the high-powered ice ramming common to her operations. The shell plating and associated internal support structure are fabricated from steel that has especially good low-temperature strength. The portion of the hull design to ram ice is 1-3/4 inches thick (4.5 centimeters) in the bow and stern sections, and 1-1/4 inches thick (3.175 cm) amidships. The hull strength is produced almost entirely from the massive internal support structure. Polar Star's hull shape is designed to maximize icebreaking by efficiently combining the forces of the ship's forward motion, the downward pull of gravity on the bow, and the upward push of the inherent buoyancy of the stern.The curved bow allows Polar Star to ride up on the ice; then the bow is levered through the ice like a giant sledge hammer.
With such a sturdy hull and high power to back it up, the 13,000-ton (13,200-metric ton) Polar Star is able to ram her way through ice up to 21 feet (6.4 meters) thick and steam continuously through 6 feet (1.8 meters) of ice at 3 knots (5.6 kph).
Polar Star has other unique engineering features designed to aid in icebreaking. An installed heeling system can rock the ship to prevent getting stuck in the ice. The system consists of three pairs of connected tanks on opposite sides of the ship. Pumps transfer a tank's contents (35,000 gallons, 133 kiloliters) to an opposing tank in 50 seconds and generate 24,000 foot-tons (64,800 kilowatt-seconds) of torque on the ship. That goes a long way in rocking Polar Star loose from any tight spots.
Duty on an icebreaker is long and strenuous, especially when it involves being away from homeport for up to eight months out of the year. Careful consideration has been given to meet the needs of Polar Star's crew of 15 officers and 126 enlisted. The ship has four sizable lounges, a library, a gymnasium, and a smallship's store. We also have our own U.S. Post Office, satellite pay telephones, amateur radio equipment, photo lab, and movie library. Bright colors and modern decor differ sharply from traditional military shipboard drabness.
Polar Star carries two helicopters during major deployments. They support scientific parties, do ice reconnaissance, cargo transfer,and search and rescue as required. The Aviation Detachment comes from the Polar Operations Division at Coast Guard Aviation Training Center, Mobile, Alabama.
Polar Star has a variety of missions while operating in polar regions. During Antarctic deployments, our primary missions include breaking a channel through the sea ice to resupply the McMurdo Research Station in the Ross Sea. Resupply ships use the channel to bring food, fuel, and other goods to make it through another winter. In addition, to these duties, Polar Star also serves as a scientific research platform with five laboratories and accommodations for up to 20 scientists. The "J"-shaped cranes and work areas near the stern and port side of ship give scientists the capability to do at-sea studies in the fields of geology, vulcanology,oceanography, sea-ice physics and other disciplines.
Operations in the remote, hazardous and unforgiving polar regions make it necessary for the crew of Polar Star to be highly self sufficient. The crew consists of personnel trained in navigation, engineering, welding, machinery repair, electronics, boat handling, firefighting, damage control, diving, medicine, and nearly every other kind of special skill that could possibly be needed.
from web site: http://www.uscg.mil/pacarea/polarstar/pstar.html