One of the most dreaded phrases for the morale of the military is “friendly fire,” when death and destruction are brought down on helpless comrades by their own forces or allies. One of World War I’s most distressing incidents of friendly fire took place in August 1918, northeast of Barnegat Light.

The story begins with the U.S. declaration of war on Germany in 1917. Fear of U-boat attacks led the Navy to construct a class of 110-foot wooden “submarine chasers,” armed with one gun and depth…