USCGC Planetree (WAGL/WLB-307) was a Mesquite-class seagoing buoy tender operated by the United States Coast Guard. She served during World War II, the Korean War, and the Vietnam War, as well as in a variety of domestic missions.
Construction and characteristics
Planetree was built at the Marine Ironworks and Shipbuilding Company yard in Duluth, Minnesota. Her keel was laid down on December 4, 1942. The ship was launched on March 20, 1943. Her original cost was $872,876.
Her hull was constructed of welded steel plates framed with steel I-beams. As originally built, Planetree was long, with a beam of , and a draft of . Her displacement was 935 tons. While her overall dimensions remained the same over her career, the addition of new equipment raised her displacement to 1,025 tons by the end of her Coast Guard service.
She was designed to perform light ice-breaking. Her hull was reinforced with an "ice belt" of thicker steel around her waterline to protect it from punctures. Similarly, her bow was reinforced and shaped to ride over ice in order to crush it with the weight of the ship.
Planetree had a single stainless-steel five-blade propeller driven by a diesel-electric propulsion system. Two Cooper-Bessemer GND-8 4-cycle 8-cylinder Diesel engines produced 700 horsepower each. They provided power to two Westinghouse generators. The electricity from the generators ran a 1200-horsepower Westinghouse electric motor which turned the propeller.
She had a single cargo boom which had the ability to lift 20 tons onto her buoy deck.
The ship's fuel tanks had a capacity of approximately . Planetree's unrefueled range was at 13 knots, at 12 knots, and at 8.3 knots. Her potable water tanks had a capacity of . Considering dry storage capacity and other factors, her at-sea endurance was 21 days.
Her wartime complement was 6 officers and 74 enlisted men. By 1964 this was reduced to 5 officers, 2 warrant officers, and 42 enlisted personnel.
Planetree was armed with a 3"/50 caliber gun mounted behind the pilot house. She also had two 20mm guns, one mounted on top of the wheelhouse and one on the aft deck. Two racks of depth charges were also mounted on the aft deck. All of this armament was removed in 1966 leaving Planetree with only small arms for law enforcement actions.
At the time of construction, Planetree was designated WAGL, an auxiliary vessel, lighthouse tender. The designation was system was changed in 1965, and she was redesignated WLB, an oceangoing buoy tender. Her namesake is the plane tree, a genus of trees which includes sycamores.
Great Lakes service
Planetree was commissioned on November 4, 1943, and began her career in the Great Lakes. In early December 1943 she was icebreaking in Lake Superior to keep the port of Ashland, Wisconsin open for iron ore shipments. On December 10, 1943, the Canadian steamship Sarnian went aground off Point Isabella on the Keweenaw Peninsula during a storm. Covered in ice and pounded by high seas, her hull plates cracked, and she was abandoned three days later. Her crew of 22 was rescued by Planetree.
Planetree spent the winter of 19431944 icebreaking in the Great Lakes. She was the first vessel of the season to reach Sault Ste. Marie by breaking ice in the Saint Mary's River in March 1944.
Pacific service
In June 1944 Planetree was assigned to a new homeport, Honolulu, Hawaii. During her transit from the Great Lakes she stopped at the Coast Guard Yard in Curtis Bay, Maryland. Tenders sailing for war zones were equipped with extra firefighting pumps, welding equipment, and diving gear. Once she reached Hawaii, one of her tasks was to deliver updated LORAN equipment to remote stations at Baker, Gardner, and Atafu Islands, which she accomplished in 1945.
The end of World War II in 1945 created intense pressure from conscripted members of the armed forces and their families for rapid demobilization. The Coast Guard lost so many sailors that it was forced to decommission several ships for lack of crews to sail them. Planetree was decommissioned in March 1947 and held in reserve at the Pearl Harbor Naval Shipyard. On September 1, 1949 Planetree was recommissioned and assigned to Guam. She was responsible for maintaining aids to navigation across a swathe to the Pacific from Okinawa to Eniwetok to Saipan. She also supplied remote bases. For example, on September 23, 1954, she arrived at Angaur, an island in Palau, towing a barge with about 8,000 gallons of diesel fuel for the LORAN station there.