The Long Blue Line: Caribbean tender Acacia and Nazi sub U-161

. . . at daybreak, a shot was heard three points off the ship’s starboard bow. It was not long before the surfaced U-161, a type IXC German U-boat, came into view.

CDR C. Douglas Kroll, Ph.D., Bulletin of the C.G. Academy Alumni Association

The combat action noted above began on Sunday, March 15, 1942. It was also the last day in the life of Coast Guard buoy tender Acacia–the only Coast Guard vessel lost to hostile fire in southern American waters during World War II.

The buoy tender Acacia’skeel was laid in Milwaukee, Wisconsin, in October 1918 as one of 10 Army Mine Planters (AMP). Like the other AMPs, the little vessel was named for an Army officer. Launched in September 1919, the tender bore the name of General John P. Story, one-time chief of Army artillery. The tender’s career as an AMP vessel would be a short one. After a few months working in New York Harbor, the tender was transferred to the Chesapeake Bay Coastal Defense System based at Fort Monroe in Hampton, Virginia. The tender would spend its Army career in this area planting contact and electrically detonated mines defending the approaches to Chesapeake Bay and Norfolk, Virginia.

By 1920, the Army faced a material surplus and budget decrease. Consequently, the Gen. John P. Story and several sister ships were transferred to the United States Lighthouse Service to serve as lighthouse tenders. These ships required a series of structural modifications for their new mission, including a rounded bow covering called a “turtleback” and higher mounted anchors. These changes were meant to prevent buoy chains and aids-to-navigation apparatus from tangling during maintenance work.

In 1927, the conversion to Lighthouse Service work was complete and the tender re-commissioned USLHT Acacia. The Acacia was assigned to the 9^th Lighthouse District in San Juan, Puerto Rico, where it arrived in April. During the next 15 years, Acacia would become a familiar sight from Guantanamo, Cuba, to the Panama Canal Zone. The tender’s main duties were to place and maintain aids to navigation, supply lighthouses, and repair access piers and other commercial maritime safety structures.

As became customary for lighthouse tenders in the Caribbean, Acacia also served local civilian and maritime authorities. It performed border security, customs law enforcement, search and rescue, medical evacuations and disaster relief missions. Following the disastrous 1928 San Felipe Hurricane, Acacia provided much needed relief supplies to isolated coastal communities. The tender evacuated many in need of medical attention and then participated in the arduous re-supply and rebuilding of damaged lighthouses and other aids to navigation. Four years later, during the 1932 San Ciprian Hurricane, Acacia sought refuge at Culebra Island east of Puerto Rico. However, the storm forced the tender aground and had to be refloated and repaired before resuming its duties.

In March 1934, the governor of the Virgin Islands commended the Acacia and its crew for transferring to St. Thomas a U.S. Public Health Service doctor and specialized blood serum to assist with numerous blood poisoning cases. In 1937, Acacia’s crew was mentioned again in the U.S. Lighthouse Bulletin after rescuing local fishermen from their capsized boat in the treacherous waters in front of El Morro Castle. That same year, the tender was first responder for an aircraft crash in San Juan Bay near Isla Grande Airport. Sadly, the aircraft’s occupants did not survive.

In 1938, Acacia gained world-wide notoriety when it assisted the Brazilian Navy Training Ship Almirante Saldanha. On a good will mission to the United States, the Almirante Saldanha had left New York on May 25. A few days later, the tall ship made its approach to San Juan Harbor’s main channel, however, the ship’s navigator mistook the tip of the Isla de Cabras for the entrance to San Juan Bay. The ship ran aground in the shallows of the Palo Seco and Coast Guard cutters Unalga and Marion tried to pull the ship into deeper water. This salvage operation proved unsuccessful, so Acacia lightened ship by taking off most of the sail training ship’s crew and cadets, and heavy equipment. It took several days before the Almirante Saldanha was refloated and docked in San Juan.

In 1939, President Franklin Roosevelt signed an executive order placing the U.S. Lighthouse Service under the Coast Guard, and Acacia received the Coast Guard designation of WAGL-200. On November 1, 1941, as war approached, oversight of Acacia was transferred from the Coast Guard to the U.S. Navy’s 10^th District in San Juan. Following U.S. entry into the war, the tender’s aids-to-navigation and support missions gained heightened importance with the creation of the Caribbean convoy system for shipping vital supplies of oil and bauxite. In addition, Acacia supported the newly developed U.S. and United Kingdom naval and air forces in the Caribbean with fuel, supplies and war material.

While completing a supply mission to the Antigua Air Station in the British Leeward Islands, Acacia was detoured to assist a disabled Gulf Oil tanker in the central Caribbean Sea. The tender towed the tanker to the British occupied Dutch Island of Curacao. Acacia was held in Willemstad, Curacao, for a month due to heavy U-boat activity nearby. While in Curacao, the tender was assigned to Willemstad Harbor’s submarine net. However, several weeks later, the British captain-of-the-port deemed it safe for Acacia to return unescorted to the Antigua Naval Base.

On Friday, March 13, 1942, Acacia departed Willemstad—it was the last time friendly forces would see the tender. Two days later, at daybreak, the buoy tendercame under fire from the deck guns of the German submarine U-161. As U-161’s rounds found their mark, Acacia caught fire and, within an hour, sank by the stern. Miraculously, only four out of the crew of 35 men were injured and none seriously. Acacia’s crew were rescued hours later by the destroyer USS Overton and returned to San Juan two days later. U-161 survived another year and, in September 1943, was attacked by Allied forces and sunk off the coast of Brazil.

Today, Acacia rests on the Caribbean sea floor at coordinates 16°17′N 63°44′W about 80 miles southwest of the islands of Saint Kitts and Nevis. The Acacia was the only Coast Guard vessel lost to enemy action in southern American waters during World War II. The valiant tender represents another chapter in the history of the long blue line.