Polar Sea Uses FT4 Gas Turbine Power To Reach North Pole

The Polar Sea, one of the U.S. Coast Guard's two Polar class icebreakers, on its way to the North Pole and accompanied by the Canadian icebreaker Louis S. St. Laurent, lost one of the starboard propeller blades and the retaining ring from the associated sterntube bearing. With the starboard prop out of commission it was not possible for the Polar Sea's dieselelectric motor systems to provide enough power to break through the thickening ice. The output of the vessel's three diesel-motor systems, normally 18,000 hp, was 12,000 hp with the loss of the starboard shaft. ThePolar Sea engaged one of its three 20,000-hp FT4 gas turbines, supplied to the USCG in 1976 by Turbo Power & Marine Systems, to power the center propeller and a diesel-motor to power the port propeller. The Polar Sea reached the North Pole Aug. 22. For the return voyage, the Polar Sea continued to take its lead turn in breaking ice by alternating port and center shaft power between the FT4s and the diesel-electric systems.