K-Ships vs. U-Boats

In January 1942, the war that had been raging in Europe arrived in the waters along the east coast of the United States. Although the United States had already experienced World War II in the Pacific with the attack on Pearl Harbor and other U.S. territories in December 1941, the start of the war in the Atlantic caught many military leaders by surprise. In mid-January, the German navy officially launched Operation Paukenschlag, a campaign of five submarines (often referred to as U-boats) to sink merchant ships carrying vital war supplies to Allied armies in Great Britain, Russia, and North Africa. In only a few short weeks, German U-boats sunk over 20 merchant vessels carrying thousands of tons of war material. The U-boats returned to their ports only after they expended all their torpedoes. To counter this new threat to maritime security, the U.S. Navy unleashed a new weapon to provide anti-submarine warfare: the K-Type blimp.

When the United States entered World War II, it only had six lighter-than-air vehicles available for use to hunt U-boats. The four completed K-Type blimps, or K-ships, in the Navy’s arsenal were in the air almost immediately after the U-boat attacks started in January 1942. The K-ship K-3 was sent to patrol the waters off Long Island, New York shortly after a U.S. tanker was sunk in that area on the night of January 14. K-3 patrolled the region, looking for oil slicks and other signs of a possible submarine. As the crew of the K-3 searched the seas, they learned from a nearby airplane that survivors had been found from the sunken tanker. Once at the location, K-3 lowered water and food to the survivors and flew in the area until surface ships could arrive. K-ships continued to serve as search-and-rescue craft during their long patrols for the length of the war. They often carried extra supplies, medical equipment, and inflatable lifeboats that could be lowered to crews from sunken ships or downed aircraft. It was difficult for K-ships to pick up these survivors, but they would ensure their rescue by directing other aircraft and surface ships to areas where survivors were located. Although the K-ship’s low-speed, long flight duration, and excellent visibility allowed their crews to be proficient in search-and-rescue operations, it also allowed them to be highly proficient in the art of anti-submarine warfare.

K-ships were also able to launch attacks. They were often loaded with a variety of ordnance, and what they carried changed throughout the war as new weapons systems became available. K-ships could carry up to four weapons, varying from 350-pound Mk 47 depth bombs, Mk 17 depth charges, or Mk 24 mines/acoustic torpedoes. Two of these could be located within an internal bomb bay and two could be located externally on the control car. They were also armed with a 50-caliber machine gun located in a turret located in the front of the control car that had a wide range of movement. If a K-ship located evidence that a submarine was in the area, it could drop its ordnance to damage the submarine, or at least make it surface, until reinforcements arrived. The K-ship’s ability to make these attacks allowed them to defend convoy ships, and several managed to damage submarines or assist in sinking them. It was dangerous work and similar attacks led to the downing of one K-ship by enemy fire.

The destruction of U-853 and capture of U-858

On May 5, 1945, the U.S. collier Black Point was sunk off the coast of Rhode Island. Several ships, including the destroyer Ericsson, Coast Guard frigate Moberly, and destroyer escorts Atherton and Amick, quickly arrived at the area in order to hunt down the U-boat responsible for the attack. The K-16 and K-58 were dispatched to the area on May 6 to help with the search for the submerged submarine. After arriving on the scene, the K-16 used its MAD equipment and located a target below the water. Following depth charge attacks by the surface ships, the K-16 deployed a sonobuoy, and detected sounds below the surface. It proceeded to drop its depth charges on the submarine’s suspected location. The K-58 then used MAD equipment to mark possible locations and dropped two depth charges of its own. After several more rounds of depth charge attacks from the surface ships, the K-ships noted numerous pieces of debris floating on the surface, marking the last destruction of an enemy U-boat in American waters.

The last World War II contribution of K-ships in the Atlantic occurred shortly after the war ended. On May 14, 1945, the captain of U-858 surrendered to the U.S. Navy. A K-ship helped escort the submarine into port, marking the end of anti-submarine warfare duties for K-ships in the battle of the Atlantic.
K-ships provided critical protection to convoys carrying the vital supplies needed to win World War II. In his work, Blimps and U-Boats, J. Gordon Vaeth explained:
The blimp stayed with the convoy, flying low and throttling back to keep a slow pace. To the men of the freighters and tankers, the protection provided by an airship was a personalized thing. Airship crews and merchant ship crews waved to each other, the airship looking all the while majestic and overwhelmingly powerful and reassuring as it threaded its way through a convoy or kept station abreast and ahead of it. The men in the blimps reciprocated this feeling of camaraderie. The same merchant ships plying the same coastal routes became familiar sights (pg. 69).

The Navy’s lighter-than-air forces, including K-ships, flying over both the Atlantic and Pacific Oceans, completed almost 36,000 flights totaling 412,000 flight hours. The destruction to convoys feared early in the war caused by marauding U-boats diminished dramatically once K-ships started keeping a constant vigil overhead and while searching for the enemy below. By the end of the war, 72 members of the Navy’s lighter-than-air forces paid the ultimate price to safeguard the merchant fleet and protect the lifeline they provided to hundreds of thousands of men, women and children.

If you would like to read more about the role of lighter-than-aircraft in World War II, please read “Blimps and U-boats: U.S. Navy Airships in the Battle of the Atlantic” by J. Gordon Vaeth.