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Sweetgum, 1943

WAGL / WLB-309

A North American tree of the genus Liquidambar having prickly spherical fruit clusters and fragrant sap.

Builder: Marine Iron and Shipbuilding Co. Duluth, MN

Keel Laid: 21 Feb 1943

Launched: 15 April 1943

Commissioned: 20 November 1943

Decommissioned: 15 Feb 2002

Cost: $ 871,619

Length: 180’

Beam: 37’

Draft: 12’

Displacement: 935 tons

Propulsion: 1 electric motor connected to 2 Westinghouse generators driven by 2 Copper-Bessemer diesels, 1200 SHP, one propeller

     Max: 13 knots, 8,000 mile range
     Cruising: 12 knots, 12,000 mile range
     Economic: 8.3 knots, 17,000 mile range

Fluid Capacities (in gallons):
     Diesel Oil: 28,660
     Potable Water:

Deck Gear: electric 20 ton boom


Armament: 1 3”/50; 4 20 mm/80, 2 dc tracks; 2 Mousetraps; 4 Y-guns

Small Boats:

Complement: 80 

     Radar: SL-1
     Sonar: QBE-3A

Class History:

When the US Coast Guard absorbed the Bureau of Lighthouses on 1 July 1939, Juniper, a 177-foot all welded steel buoy tender, was under construction and plans for a successor were on the drawing board. Plans initiated by the Bureau of Lighthouses called for the construction of several identical buoy tenders to replace existing coastal buoy tenders. The preliminary designs generated by the Bureau were for a vessel similar to Juniper. When the Aids to Navigation (ATON) system transferred to Coast Guard control, USCG planners reviewed the preliminary plans for the new class of buoy tenders and modified them to meet the service’s multi-mission role. To be an effective part of the Coast Guard, the new buoy tenders needed to be multi-purpose platforms. They had to be capable of conducting Search and Rescue (SAR) and Law Enforcement (LE) missions, as well as their primary mission tending ATON. On 20 January 1941 the US Coast Guard contracted Marine Iron and Shipbuilding Company of Duluth , Minnesota to build the design based on Juniper and modified to meet the service’s requirements. On 31 March 1941 Marine Iron and Shipbuilding laid the keel for the first vessel of the new buoy tender class. The new vessel measured 180 feet overall and had a beam of 37 feet at the extreme. She had a displacement of 935 tons and drew 12 feet. The new design was similar to Juniper in appearance but did exhibit some important differences. Gone was the turtle back forecastle. A notched forefoot, ice-belt at the waterline, and reinforced bow gave the vessel icebreaking capabilities. Extending the superstructure to the ship’s sides increased interior volume above the main deck. A single propeller, turned by an electric motor powered by twin diesel generators, replaced the twin-screw arrangement. The 30,000-gallon fuel capacity gave the new design a range of 12,000 miles at a 12-knot cruising speed; at 8.3 knots the cruising range increased to 17,000 miles. Finer lines at the bow and stern increased the new tender’s sea keeping ability in rough weather; an increase in draft also promoted seaworthiness. Numerous minor alterations increased the vessel’s utility as a SAR platform while deck-mounted guns and depth charge racks supported military duties. Marine Iron and Shipbuilding launched the prototype vessel on 25 November 1941, even as three more took shape. Preparations also went forward to begin a fifth vessel. By the time they commissioned the first 180, Cactus, on 1 September 1942 twelve vessels were under construction at the Marine Iron shipyard and at the Zenith Dredge Company shipyard, also in Duluth . The initial designation for the new buoy tenders was WAGL, which was a US Navy designation denoting an auxiliary vessel, lighthouse tender. The designation changed from WAGL to WLB in 1965. A few of the 180s have been designated as other types of vessels over the years; three became WMECs (medium endurance cutters), one of those, Evergreen, was a WAGO (oceanographic research vessel) before it became a WMEC. Gentian was a WMEC for a time and was then designated a WIX (Training Cutter) in 1999. Though designations have changed over time, each vessel’s hull number has remained the same since commissioning.


Six “B” or Mesquite class tenders followed the initial production run of thirteen vessels in the “A’ or Cactus-class. The first Mesquite-class tender hit the water on 14 November 1942. Marine Iron and Shipbuilding built all except one of the Mesquite-class. The USCG built the lone exception, Ironwood, at the service’s shipyard in Curtis Bay, Maryland. Twenty Iris or “C” class vessels followed the Mesquite-class tenders. The first launch of an Iris class vessel took place on 18 June 1943, and the final addition to the class slipped off the ways on 18 May 1944. Differences among the three classes were minimal. Their basic dimensions, length and beam were the same and draft varied based on loading. All were built of welded steel along the same framing pattern and with very similar internal and external layouts. All three classes could steam 8,000 miles at 13 knots, 12,000 miles at 12 knots, and 17,000 miles at 8.3 knots; though the “B” and “C” class vessels had engines with 20 percent more power than the “A” class. The “A” class vessels could carry the most fuel with a tank capacity of 30,000 gallons. The “C” class carried 29,335 gallons and the “B” class about 700 gallons less. The layout of the Commanding Officer’s cabin and the radio room was slightly different in the “A” class vessels. The bridge wing door on the “B” and “C” vessels opened to the side while the doors on the “A” vessels opened forward. The cargo holds as originally laid out in the “C” were larger, by a nominal amount, than those in the other vessels. To hoist buoys and cargo, the “A” vessels carried an A-frame structure that straddled the superstructure and supported the cargo boom. The other two classes were fitted with power vangs that attached to the bridge wings and manipulated the cargo boom. The “A” vessels were originally fitted with manila line as part of the cargo handling system while the second and third generation vessels used wire rope. From the outside, other than the A-frame used in the first production run, the three classes were almost indistinguishable. Over the years their internal differences and variation in equipment were minimized by successive overhauls and improvements. Moreover, it does not appear that any one of the three classes was superior to the other two in the eyes of the US Coast Guard administration or the men who manned the buoy tender fleet. Tenders from each of the three classes remained in use past the turn of the 21st century. It usually took from two to four months between the time shipyard workers laid a keel and the day the vessel slipped off the ways. Once launched, however, the tenders were far from ready for service. The practice was to build the superstructure, finish the interior, and complete the machinery installation while the vessel was floating. Hence, on launch day the tenders were little more than finished hulls. As the shipyard workers neared the end of the building process, the Coast Guard would begin assigning officers and men to the vessels. Once each vessel was complete and ready to enter active service, the US Coast Guard commissioned her as part of the fleet. Often the commissioning ceremonies took place after the tender had departed from Duluth and arrived at an initial duty station. For the 180s as a whole, it took an average period of 308 days to go from the beginning of construction to commissioning. Divided according to sub-class, the elapsed time from keel laying to commissioning averaged 360 days for the Cactus-class; 323 days for the Mesquite-class; and 269 days for the Iris-class. The building process averaged 192,018 man-hours of labor per vessel. In keeping with the Lighthouse Service practice of naming tenders after foliage, all of the 180s were named after trees, shrubs, or flowers.

Cutter History:

Sweetgum, a 180-foot Mesquite or B-Class tender, was built in Duluth, Minnesota by the Marine Iron and Shipbuilding Company.  Her keel was laid on 21 February 1943.  She was christened and launched on 15 April 1943.  She was commissioned on 20 November 1943 under the command of LT S.E. Hunshete.

Her first homeport was Grand Haven, Michigan, where her primary duties were aids to navigation (ATON) and ice breaking in the Great Lakes.  Then in March 1944 her homeport was changed to Miami, Florida.  She served in World War II as an armed escort for Europe-bound convoys and later as a submarine net tender and was also used for aircraft salvage in the Atlantic.  On 2 August 1945 LT Clarence Samuels, the Coast Guard's first African-American officer, took command of Sweetgum.  LT Samuels remained in command until he was transferred on 3 January 1946.  

On 1 September 1946 her homeport was changed to Mayport, Florida, where she remained until transferred to Mobile, Alabama.  Her primary duties were ATON and search and rescue missions, though she also performed law enforcement and homeland security patrols, aided mariners in distress, supported military operations, responded to natural and man-made disasters, and educated the public. While in Mayport, she was responsible for maintaining 333 buoys and ATON structures from Kings Bay, Georgia to the Bahamas.

Though she engaged in many operations over the years, there are several worth pointing out as unique.  On 17 July 1951 she searched for the Eastern Airline flight Constellation 611 that went down 120 miles east of Jacksonville, Florida.  In 1967 she was an integral part of Operation Sunken Tanker, a military research program to determine the potential threat to the U.S. coastline from the cargo of 103 sunken oil tankers from World War II.  Divers investigating the wreck of the Norwegian tanker SS Varanger discovered no oil remaining but did locate a large safe that was hoisted aboard Sweetgum.  Upon opening the safe though the crew discovered only a few coins and some Philadelphia subway tokens.  

In 1977 she was part of the National Strike team, which cleaned up 400,000 gallons of oil spilled in the Hudson near West Point, New York, when a barge ran aground.  She was also charged with icebreaking to open up shipping routes and freeing frozen-in ships.  She was awarded the Coast Guard Meritorious Unit Commendation in 1978 for "meritorious service and exemplary performance of specially assigned aids to navigation and an emergency helicopter recovery mission and display of an extremely high level of professionalism and dedication to duty during the period of 20 March to 1 May 1978."

In 1986 she engaged in the Space Shuttle Challenger recovery operations in which she steamed 1200 nautical miles and searched over 410 square miles.  She recovered many items including the booster rocket nose cone, which still held explosives.

On 2 February 1990 she was temporarily decommissioned to be renovated (Service Life Extension Program: SLEP) at the Coast Guard Yard at a cost of $15 million.  She was then transferred to Mobile on 1 December 1991 and was formally recommissioned there on 10 January 1992. 

While at Mobile she was responsible for maintaining 120 aids to navigation and ATON in two of the nation's busiest ports, Mobile and New Orleans, Louisiana.  In 1994 she assisted in the Sunset Limited Amtrak bridge accident recovery.  

She has provided disaster relief for several hurricanes (1989, Hugo; 1995, Opal; 1997, Danny; 1998, Earl and Georges; 1999, Bret).

Then on 15 February 2002, after a superb career, she was decommissioned and replaced by a newer model of tender.  Sweetgum was then transferred to Panama.  Panama's National Maritime Service (SMN) christened her SMN Independencia and gave her the hull number of 401.

Researched and written by Ms. Melissa M. Ashmore. 

USCGC Sweetgum

Original caption: "SWEETGUM, Underway"; dated 19 November 1943; Photo No. 697; photographer unknown.

USCGC Sweetgum

No caption/date; Photo No. 080867; photographer unknown.

USCGC Sweetgum

Original caption: "SWEETGUM"; dated 1970; Photo No. CGD7 103170; photographer unknown.

USCGC Sweetgum

Original caption: "Sweetgum (WLB-309) 180-ft "B" Class Buoy Tender."; dated 31 October 1970; No photo number; photographer unknown.


Cutter History File.  USCG Historian's Office, USCG HQ, Washington, D.C.

Robert Scheina.  U.S. Coast Guard Cutters & Craft of World War II.  Annapolis, MD: Naval Institute Press, 1982.

Robert Scheina.  U.S. Coast Guard Cutters & Craft, 1946-1990.  Annapolis, MD: Naval Institute Press, 1990.

U. S. Department of the Interior.  National Park Service. U.S. Coast Guard 180-Foot Buoy Tenders.  HAER booklet.  Washington, DC: National Park Service, September, 2003.   [HAER nos. DC-56, LA-14, LA-15, RI-56, and AL-187; Todd Croteau, HAER Industrial Archeologist ( project leader); Jet Low, HAER Photographer; Dana Lockett (architect); Pete Brooks (architect); Candace Clifford (historian); and Kevin Foster (historian).] 

Last Modified 1/12/2016