Icebreaking in the U.S. began in the 1830s, with the advent of steam propulsion. Side-wheel steamers with reinforced bows proved excellent for dealing with harbor ice, a problem common to East Coast ports as far south as the Chesapeake Bay. These seasonal tasks were common, but were strictly local efforts.
The RCS became involved with ice operations in support of traditional missions that were impossible in winter without preparations for ice. The major impetus behind domestic icebreaking came with the nation’s acquisition of Alaska in 1867, nearly a third of which lies above the Arctic Circle. Early vessels such as Thetis and Bear had reinforced hulls, making them ice resistant. They began the Bering Sea Patrol in 1880, but were not capable of true polar work.
Apache and Ossipee both had hulls strengthened for ice duty. Apache underwent strengthening in one of her rebuilds, probably in 1905, and was assigned to the Chesapeake Bay area, where light ice breaking is sometimes necessary. Ossipee was a 165′ steel cutter, commissioned in 1915 and assigned to the New England coast.
Androscoggin, commissioned in 1908, was purposely built as a cutter “for the coast of Maine” and to “break through the ice along the Maine coast for the relief of shipping.” She had machinery that developed 1,600 horsepower, a spoon bow and was strongly built of white oak, with steel reinforcement and frame. There are also indications that she was later given a metal casing for her prow. She was the last major naval to have a wooden hull.
By the late 1920s, the Coast Guard was fully committed to domestic ice operations, still mostly in support of traditional missions and still focused primarily on Alaska. In the 1920s the Service committed to designing ships that were capable of ice operations. The 240s were designed to operate in ice as was Northland.
In late 1926, a purchased ocean tug, Kickapoo, was docked and rebuilt as an icebreaker. In order to use her in shallow harbors she was widened by eight feet, reducing her draft, then an entirely new icebreaker bow, similar to that of the Northland, was built on her. Her duty station was the coast of Maine, to replace Androscoggin, which was sold in 1922.
The six 165A class cutters were designed to operate in ice. Their bows were moderately cut away at the forefoot, the plating was doubled on their bows. They joined the Fleet in the early 1930s and were intended for light icebreaking on the Great Lakes but proved only sufficient to ‘chip away’ at the ice in the early season. The Calumet-class harbor tugs Calumet, Hudson, Navesink and Tuckahoe entered the Fleet in the early ‘30s and were capable of light icebreaking.
On 21 December 1936, the Coast Guard received the first statutory authorization for icebreaking operations. It had become apparent that clear seaways and ports were vital for the passage of fuel oil barges in the winter months along the New England coast. This led to President Roosevelt’s order directing the Coast Guard “to assist in keeping open to navigation by means of icebreaking operations…channels and harbors within the reasonable demands of commerce.”
The Coast Guard then initiated an intensive study of icebreaker technology. From 1936 to 1941, Rear Admiral Edward Thiele spearheaded this research. He studied the Swedish vessel Ymer, considered the best icebreaker of the time. Ironically, the vital elements of her design had been copied from American sources. Her fore and aft props had been used in ferries on the Lakes, and her diesel electric power plant was the same as in Northland. The immediate upshot of Theile’s travels and study was the design of the 110-foot Raritan-class tugs. The main features of these were structural strength and a bow shape which would overcome the shortcoming of the cutaway configuration utilized in such vessels as the Northland: the lack of directional stability. In this design the “keel” projects forward and fairs into the slope of the stem providing a stabilizing element beneath the sharp upward angle of the icebreaking bow. These vessels were the first class of true icebreakers in the service, and proved eminently successful. They were: Arundel, Naugatuck, Mahoning, and Raritan, commissioned from April to August, 1939.
The 180-foot tenders were the next class of vessels with icebreaking characteristics. They had been designed by the Lighthouse Service prior to its amalgamation with the Coast Guard (1939) and naval architects introduced a cutaway forefoot and “slack” (rounded) bilges. The latter feature is more appropriate to ice work than squared bilges, as they allow the vessel to be forced upward by enclosing ice, lessening the danger of being trapped. Between 1941 and 1944, 39 of these vessels entered service. These vessels proved to be credible icebreakers, able to handle up to 20 inches of ice, as well as versatile in other areas such as antisubmarine warfare, convoy escort, weather station duty, etc.
These were followed by the 110-foot Appalache-class in 1943. These were Apalachee, Chinook, Mohican, Ojibwa, Sauk, Snohomish, and Yankton.
The two new classes of 110-foot tugs and the 180-foot tenders gave the Coast Guard a sorely needed boost in numbers of up to date light and medium icebreaking vessels. The Coast Guard also manned several Army tugs during the war. These tugs performed the same missions as Coast Guard tugs, ice breaking, fire fighting, and search and rescue.
The Fleet was enhanced by the addition of the 15 65’-class tugs in the early 1960s. From 1977 to 1987, the Coast Guard again added to its fleet of icebreaking tugboats. Nine 140-foot tugs were built to replace the aging 110-foot Raritan-class. These vessels, the Katmai Bay-class, have increased icebreaking capacity over their predecessors, incorporating a portable bubble generator system. This air lubrication apparatus is designed to assist the hull in resisting encroaching ice and improves icebreaking performance at slow speeds. Seven of the tugs were constructed by Tacoma Boatbuilding Company; two by Bay City Marine, also of Tacoma, Washington. They are Biscayne Bay, Bristol Bay, Katmai Bay, Mobile Bay, Neah Bay, Morro Bay, Penobscot Bay, Sturgeon Bay, and Thunder Bay. The last was commissioned on 12 September 1988.
The Coast Guard entered the 21st Century with the 65s and 140s.
For a complete list of Coast Guard ice breaking tugs from 1915 to 1940 go to this Link.
For a complete list of Coast Guard ice breaking tugs of the WWII era go to this Link.
For a complete list of all Coast Guard icebreaking tugs go to this Link.