JR Potts, AUS 173d AB (Updated: 8/27/2013):
HMS Upholder started her trials in September of 1940 and, upon completion of her requisite crew training, she left for her first assignment on December 10th and posted to the 10th Submarine Flotilla based at Malta. The Mediterranean Sea was a complex operating area for submarines, deep in some areas while other shallow in others. The waters proved shallow enough for an attacking submarine to accidentally hit the bottom when diving. Vessels on or in the clear Mediterranean waters were also relatively easy to spot from the air. Other problems experienced by the 10th Submarine Flotilla including naval mines, small sub-chasers in the coastal waters and land-based enemy spotting aircraft. Fresh water rivers also emptied into the Mediterranean. River water generally proved to be less buoyant and would not support submarines, leading to passing subs plunging 100 feet or more without warning.
Times were dangerous as the 10th Submarine Flotilla lost three submarines on patrol. However HMS Upholder, under the command of Lt. Commander Malcolm Wanklyn, was showing promise when, on her first patrol, she sunk an 8,000 ton enemy supply ship. Early in 1941, the German Luftwaffe bombed Malta daily in an attempt to try and break the British hold of the island. Many British aircraft had been destroyed except for a few Wellingtons and Swordfish and these were capable of attacking enemy shipping. British anti-aircraft gun defenses on the island were the negligible threat to the German Luftwaffe.
By September of 1941, two more boats had been sunk by the Germans. HMS Upholder was starting her 14th patrol with three other U-class boats in an effort to locate and sink enemy troop ships sailing for Tunisia. The four submarines took up positions across the ships route near Sirte. Three Italian transports had a screen of six destroyers and approached Upholder's position. She alone attacked the nine heavily-armed enemy ships. Wanklyn penetrated the destroyer screen and fired three torpedoes over a distance of five thousand yards.
Wanklyn scored three hits out of the three torpedoes launched against the transports. Two torpedoes hit the SS Neptunia and one hit the SS Oceania. The Neptunia was heavily damaged and Oceania's propellers were completely blown off. The third transport, the SS Vulcania supported by one of the destroyers, departed the area. SS Neptunia eventually sank while the accompanying destroyers collected survivors and, upon finishing the task, steamed to the aid of SS Oceania who, at this point, lay dead in the water. Upholder surfaced and fired two torpedoes across one mile at the destroyers protecting SS Oceania, hitting and sinking one destroyer inthe process. The SS Oceania later sank. On April 6th, HMS Upholder left on her 25th and final patrol before she was scheduled to return to England. However, she never returned and the exact cause of her sinking went largely unknown. She was listed as missing on April 14th, 1942, believed to have been the victim of an Italian submarine hunter.
HMS Upholder (P37) had the most successful record of any British submarine in World War 2. During her 24 patrols against enemy shipping in the Mediterranean Sea, she made 36 torpedo attacks resulting in the sinking of 21 total ships for over 90,000 tons claimed: 15 German and Italian transports and supply ships, 3 German U-boat submarines, 2 Destroyers, and 1 armed trawler.
Lieutenant Commander Wanklyn received the prized Victoria Cross for his service.