Sunken Ships on April 18th
HMS P615 - The Oruç Reis-class submarine was torpedoed and sunk in the Atlantic Ocean by U-123 with the loss of all 43 crew.
HMS Regent - The Rainbow-class submarine struck a mine and sank in the Strait of Otranto with the loss of all 63 crew
L-6 - The Leninets-class submarine was sunk in the Black Sea east of Constanta, Romania by UJ-104.
USS Gudgeon - The Tambor-class submarine was bombed and sunk in the Pacific Ocean off Iwo Jima by a Mitsubishi G3M "Nell" bomber of the 901 Air Group.
I-56 - The Type B1 submarine was sunk in the Pacific Ocean off Okinawa by USS Collett, four other destroyers and United States Navy carrier-based aircraft.
Sunken Ships on April 19th
Alpino - The Soldati-class destroyer was sunk at La Spezia by British aircraft.
U-974 - The Type VIIC submarine was torpedoed and sunk in the North Sea off Karmsund, Norway by Ula with the loss of 42 of her 50 crew.
Aquila - The ex-Italian incomplete aircraft carrier was scuttled at Genoa.
U-251 - The Type VIIC submarine was sunk in the Kattegat by a rocket attack by de Havilland Mosquito aircraft of 143, 235 and 248 Squadrons, Royal Air Force with the loss of 39 of her 43 crew.
U-548 - The Type IXC/40 submarine was depth charged and sunk in the Atlantic Ocean south east of Halifax, Nova Scotia, Canada by USS Buckley and USS Reuben James with the loss of all 58 crew.
U-879 - The Type IX submarine was sunk in the Atlantic Ocean by USS Buckley and USS Reuben James.
U-548 - The Type IX submarine was depth charged and sunk in the Atlantic Ocean off Cape Henry, Virginia, United States by USS Bostwick, USS Coffman, USS Natchez and USS Thomas (DE-102). Various dates are given by different sources; 19, 29 and 30 April.
USS Snook - The Gato-class submarine was lost in the South China Sea between 8 and 20 April, cause unknown.