1918 | April 11

Shape signals on submarine chasers

On 11 April, 1918, submarine chaser SC 354 was readying for live ASW operations, and a shipment to the chaser was prepared for crosses, drums, and cones, shape signals for use on the hunt.

Subchasers in WWI hunted in units of three: a unit leader and two wing boats. Ship-to-ship communications took several forms, from the radio telephone to the Bearing Indicator. Shape signals were three-dimensional shapes, two feet tall, suspended during hunts. In the photo overlay, the "cone" fully raised signifies "underway." (Inverted, it would be the "top" shape.)

Hunters of the Steel Sharks: The Submarine Chasers of WWI

Hunters of the Steel Sharks: The Submarine Chasers of WWI
Woofenden, 2006. Softcover, 224 pages. $23.95. Available on Amazon.com

In 1918, a war time fleet of 303 U.S. submarine chasers formed a new offensive against the enemy, armed with depth charges, deck guns and an array of new, top secret submarine detection and pursuit devices.

These miniature wooden war ships, the smallest commissioned vessels in the American navy, were the first major deployment mechanism for early antisubmarine warfare equipment, and were remarkable in their capabilities and service: Chasers crossed the Atlantic Ocean on their own power; performed submarine hunts and attacks from bases in Plymouth, Queenstown (Cobh) and Corfu; assisted with post-war diplomacy along the eastern shore of the Adriatic Sea; helped facilitate troop evacuation in northern Russia; and participated in the clearing of the North Sea mine barrage.

This is the history of the submarine chasers of the Great War, extensively illustrated with period photographs and diagrams, and rich with personal anecdotes, an up-close account of the early days of ASW based on rare, unpublished documents.