9 photos of WWII escort aircraft carriers, the US Navy's small but effective hunter-killers that defeated Germany's U-boats

Daniel Brown

Oct 10, 2018, 21:36 IST

US Navy

USS Long Island (CVE-1) underway in 1943.

Fleet-sized aircraft carriers, such as the USS Enterprise and USS Midway, captured the public's attention during the air battles of World War II.

But the majority of the US Navy's aircraft carriers during the war were actually smaller, lesser known vessels: Escort carriers.

There were five different classes of escort carriers, all of which varied slightly. But in general, they were about half the size of fleet-sized carriers.

The Casablanca-class, which had the largest number built with 50 hulls, typically carried 28 aircraft, including 12 Grumman TBF Avengers torpedo bombers and 16 F4F Wildcats fighters, Timothy Bostic, a reference librarian at the Navy Department Library, told Business Insider.

Referred to as "Jeep carriers" or "baby flap tops" by the press, escort carriers were slow, lightly armored and had few defensive weapons.

But they were also expert at hunting and killing enemy submarines, and exacted a heavy toll on Germany's U-boats.

Here's how they did it.

When German U-boats began sinking convoy ships in the beginning of the war, Great Britain asked the US for help, which responded by building escort carriers. The first escort carrier was the USS Long Island, which was built from an old freighter and launched in January 1940.

The US then built four more from oiler hulls, including the Chenango, which were sent to help with landings in North Africa, where they proved extremely successful in anti-submarine warfare. This led to the building of dozens more and deployments to the Pacific.

Escort carriers had initially been used to protect convoys, ferrying planes, among other duties. But by 1943, the US had evolved its tactics to hunt and kill U-boats.

In may 1943, the USS Bogue scored the first escort carrier kill of a German U-boat after spotting the surfaced U-231 and sent a Grumman TBF Avenger torpedo bomber after it, which released four depth bombs and took it out as it tried to submerge.

Grumman TBF Avengers were torpedo dive bombers that could drop bombs and torpedoes. The escort carriers launched them with a primitive hydraulic launch system and recovered them with a cable, Bostic, the Navy reference librarian, said.

But what led to the escort carriers' eventual success over the German U-boats was the Allies code-breaking U-boat radio traffic in 1943, providing escort carriers with accurate locations of enemy submarines.

This breakthrough also allowed the Allies to hunt and kill German U-tankers, or "Milch Cows," which refueled the short-range U-boats at sea.

This new knowledge of German U-boat and U-tankers allowed the Allies to evolve their tactics, sending escort carriers with destroyers away from their convoys to hunt and destroy the enemy submarines.

By the war's end, escort carriers had sunk a total of 53 German U-boats.

Next Story The US Army is searching for a new combat vehicle to defeat the toughest adversaries - here are 3 leading possibilities