The S-class submarine’s legacy endures as a testament to undersea warfare’s evolution, and the brilliance of early 20th century British submarine designs.
The British S-class submarine was one of the most iconic platforms belonging to the Royal Navy during the Second World War. Designed in the 1930s to replace the H-class submarines, these medium-sized patrol submarines became the most numerous class of submarine ever built for the Royal Navy, with 62 boats constructed over 15 years.
As World War II erupted, S-class subs played pivotal roles in disrupting Axis supply lines, conducting reconnaissance, and executing daring special operations. Their versatility allowed operations in diverse theaters, from the treacherous North Sea to the distant Pacific.
The S-Class Submarine Came in Three Varieties
Evolving through three main groups, each refined for enhanced performance in restricted waters, such as the North Sea and Mediterranean Sea, the S-class was a unique British submarine.
| Submarine | S-Class – First Group | S-Class – Second Group | S-Class – Third Group |
| Years Built | 1930-1932 | 1934-1937 | 1939-1945 |
| Number Built | 4 | 8 | 50 |
| Length | 202 ft (61.5 m) | 208 ft 9 in (63.6 m) | 217 ft (66 m) |
| Beam (Width) | 24 ft (7.3 m) | 24 ft (7.3 m) | 23 ft 6 in (7.16 m) |
| Displacement (Submerged) | 935 tons | 960 tons | 990 tons |
| Engine(s) | Diesel/electric; two engines surfaced, two electric motors submerged | Diesel/electric; two engines surfaced, two electric motors submerged | Diesel/electric; two engines surfaced, two electric motors submerged |
| Top Speed | 13.75 knots (15.8 mph, 25.4 km/h) surfaced10 knots (11.5 mph, 19 km/h) submerged | 13.75 knots (15.8 mph, 25.4 km/h) surfaced10 knots (11.5 mph, 19 km/h) submerged | 14.75 knots (16.9 mph / 27.3 km/h) surfaced8 knots (9.2 mph, 15 km/h) submerged |
| Range | 6,000 nmi (6,900 mi, 11,112 km) | 7,500 nmi (8,635 mi, 13,890 km) | |
| Armaments | Six 21-inch torpedo tubes forward and one aftOne 3-inch deck gunOne .303 machine gun | Six 21-inch torpedo tubes forward and one aftOne 3-inch deck gunOne .303 machine gun | Six 21-inch torpedo tubes forward and one aftOne 20mm cannonThree .303 machine guns |
| Crew | 36 | 39 |
The S-Class Submarine Terrified Axis Sailors All Over the World
During World War II, S-class subs operated across multiple fronts, adapting to the war’s demands. In home waters and the North Sea, early groups patrolled the English Channel, Bay of Biscay, and Scandinavian coasts, terrorizing German shipping and supporting Arctic convoys. But the contested Mediterranean Sea became their primary battleground, where third-group boats based in Gibraltar, Malta, and Alexandria disrupted Italian supply routes to the Axis forces in North Africa. The submarines patrolled the Adriatic, Aegean, and off Sicily, sinking merchant vessels and warships alike.
In the Far East, from 1944 onward, S-class submarines with extended fuel tanks operated in the Strait of Malacca and near Singapore, harassing Japanese forces. Key operations included convoy escorts during Operational Pedestal (Malta relief) and reconnaissance for Operation Torch (North Africa invasion). Their range and stealth enabled long patrols, often lasting weeks, where they gathered intelligence and struck opportunistically.
Several S-class submarines achieved legendary status through their bold and heroic actions. Under the command of Lt. Norman “Bill” Jewell, the S-class submarine HMS Seraph executed Operation Mincemeat—a deception involving a planted corpse with false invasion plans, misleading Axis forces before the Sicily landings. Seraph also ferried US Army Gen. Mark Clark to Algeria for secret talks, and rescued a Free French general during Operation Kingpin.
Other heroic submarines abounded. The HMS Safari sank 25 enemy ships (mostly Italian), while the HMS Splendid torpedoed the destroyer Aviere and multiple transports over a six-month period. The HMS Sahib destroyed German submarine U-301 and multiple Italian vessels before Sahib was itself lost in battle. The HMS Sportsman claimed 12 kills totaling over 20,000 gross register tons. These successes crippled Axis logistics, with S-class boats collectively sinking hundreds of thousands of tons of shipping, bolstering Allied advances.
Despite Its Losses, the S Class Was a Wonderful Boat
The hazardous nature of submarines took its toll on the S-class, however. By the war’s end, 18 of the submarines had been lost to enemy action, many to depth charges, mines, or torpedoes. Early losses included the HMS Spearfish, sunk by German U-34 in 1940, and the HMS Shark, captured after surfacing damaged. In the Mediterranean, the HMS Splendid and HMS Sahib were scuttled after relentless attacks. The third group of S-class boats built suffered nine losses—including the HMS Saracen and HMS Simoom to mines.
Despite these losses, given the sheer number of S-class submarines in service to the Crown during the war, serving aboard an S-class boat was deemed to be a relatively safe venture for the sailors assigned to these iconic submarines, as the S-class lost so few boats in the war. The relatively high survival rate of British submariners is particularly remarkable when compared to the German Kriegsmarine; of the 40,000 German sailors who served on U-boats, 30,000 did not survive the war.
After the war, many S-class subs served in the Royal Navy until the 1960s, influencing Cold War designs. Today, the vessel’s legacy endures as a testament to submarine warfare’s evolution, and the brilliance of early 20th century British submarine designs.
About the Author: Brandon J. Weichert
Brandon J. Weichert is a senior national security editor at The National Interest. Recently, Weichert became the host of The National Security Hour on America Outloud News and iHeartRadio, where he discusses national security policy every Wednesday at 8pm Eastern. He is also a contributor at Popular Mechanics and has consulted regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including The Washington Times, National Review, The American Spectator, MSN, The Asia Times, and others. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Wikimedia Commons.
