The German U-boat U-103, a Type IXB submarine of the Kriegsmarine, served with distinction during World War II. Commissioned on July 5, 1940, under the command of Korvettenkapitän Viktor Schütze, U-103 completed 11 combat patrols and sank 46 ships, totaling 238,944 gross register tons, while damaging three others. During its fourth patrol, lasting from April 1 to July 12, 1941, U-103 operated off the West African coast for 103 days, marking its most extended and successful mission. This patrol resulted in the sinking of several significant vessels, including the Polyana and the Radames. After completing its combat role, U-103 transitioned to training duties in March 1944 and remained active until its crew scuttled it in Kiel on May 3, 1945, to prevent capture by advancing Allied forces.

The German U-boat U-107, a Type IXB submarine of the Kriegsmarine, achieved significant success during World War II. Kapitänleutnant Günter Hessler commissioned the submarine on October 8, 1940, and led it through its early, highly successful missions. U-107 completed 13 patrols between January 1941 and August 1944, sinking 39 Allied ships and damaging four others. During its second patrol, from March 29 to July 2, 1941, the U-boat operated near the Canary Islands and Freetown, sinking 14 ships totaling 86,699 tons, making it one of the war’s most successful patrols. On August 18, 1944, British aircraft attacked and sank U-107 in the Bay of Biscay, killing all 58 crew members.

The USS Cavalla (SS-244) was a Gato-class submarine that played a significant role in World War II as part of the United States Navy's submarine fleet. • The USS Cavalla is best known for its role in the sinking of the Japanese aircraft carrier IJN Shokaku during the Battle of the Philippine Sea on June 19, 1944. The submarine fired six torpedoes, and at least one hit the Shokaku, contributing to the carrier's eventual sinking.

The German U-boat U-123, a Type IXB submarine of the Kriegsmarine, played a significant role in World War II. Kapitänleutnant Karl-Heinz Moehle commissioned it on May 30, 1940, and under his command and subsequent leadership by Reinhard Hardegen, U-123 embarked on 12 war patrols, sinking 45 ships totaling 224,050 gross register tons while damaging six others. During its seventh patrol, from December 23, 1941, to February 9, 1942, Hardegen led U-123 as part of Operation Drumbeat, attacking Allied shipping along the U.S. East Coast. This patrol destroyed several key vessels, including the British tanker Cyclops and the Norwegian tanker Norness. After the war, the French Navy acquired U-123, renaming it Blaison (Q165), and used it until its decommissioning on August 18, 1959.

The German U-boat U-48, a Type VIIB submarine of the Kriegsmarine, became the most successful U-boat of World War II. Kapitänleutnant Herbert Schultze commissioned it on April 22, 1939, and led it during the early stages of the Battle of the Atlantic. U-48 carried out 12 war patrols and sank 52 ships, totaling 306,874 gross register tons (GRT), while damaging three others, amounting to 20,480 GRT. During its sixth patrol from May 26 to June 29, 1940, U-48 targeted Allied shipping, including the British armed merchant cruiser HMS Andania. The crew decommissioned U-48 in October 1943 and later scuttled it on May 3, 1945, off Neustadt to avoid capture.

The German U-boat U-124, a Type IXB submarine of the Kriegsmarine, carried out an impressive wartime record during its service in World War II. Kapitänleutnant Georg-Wilhelm Schulz commissioned the submarine on June 11, 1940, and it completed 11 patrols, sinking 46 merchant ships totaling 219,862 gross register tons (GRT) and two warships amounting to 5,775 tons. U-124 also damaged four merchant ships totaling 30,067 GRT. During its fourth patrol, from February 23 to May 1, 1941, U-124 achieved remarkable success, sinking 11 ships, including four vessels near the Cape Verde Islands on March 8: Nardana, Hindpool, Tielbank, and Lahore. British warships HMS Stonecrop and HMS Black Swan intercepted and destroyed U-124 on April 2, 1943, west of Oporto, Portugal, with no survivors from its 53-member crew.

The USS Drum (SS-228) is a Gato-class submarine that played a crucial role in the United States Navy during World War II. Commissioned in 1941, the submarine conducted numerous successful patrols in the Pacific theater, earning 12 battle stars for its service. The USS Drum is particularly renowned for its daring and effective attacks on Japanese naval vessels and merchant ships. Notably, during its fifth war patrol, the Drum sank the Japanese aircraft carrier IJN Taihō, contributing to the Allied efforts in the Pacific. The submarine is now preserved as a museum ship at the USS Alabama Battleship Memorial Park in Mobile, Alabama, allowing visitors to explore and appreciate its significant role in naval history during one of the most critical periods of the 20th century.