A cruiser submarine was a very large submarine designed to remain at sea for extended periods in areas distant from base facilities. Their role was analogous to surface cruisers; cruising distant waters, commerce raiding, and otherwise operating independently. When operating in a fleet, cruisers and cruiser submarines were expected to scout for and screen the battle fleet. Cruiser submarines were successful for a brief period of World War I, but were less successful than smaller submarines during World War II. Large submarines remained vulnerable to damage from defensively equipped merchant ships (DEMS), were slow to dive if found by aircraft, offered a large sonar echo surface, and were less able to defensively maneuver during depth charge attacks.Blair, p.501
History The cruiser submarine concept originated during the unrestricted submarine warfare campaign of 1917. Three German Type U 139 submarines and seven former merchant submarines, each armed with two guns, patrolled areas distant from their North Sea bases to sink Allied merchant shipping as part of an effort to starve the UK into submission. These distant patrols avoided the defensive convoy measures which limited successful submarine attacks in the vicinity of the British Isles.Tarrant, pp.44-60
The First World War combat experience of these submarines encouraged all major navies to build submarine cruiser prototypes between the world wars. Nevertheless, their cost discouraged most from proceeding with further production. Developments were further limited by the London Naval Treaty of 1930, under which each signatory was permitted to possess no more than three large submarines, each above 2,000 tons (2,032 metric tons) but not exceeding 2,800 tons (2,845 metric tons) standard displacement, with guns not exceeding 6.1 in (150 mm) in caliber.
The Imperial Japanese Navy’s focus on forcing a decisive fleet action encouraged development of a wide variety of submarine cruisers, (known as ) including the J Type of the 1920s, and the A, B, and C types in the 1940s. Germany decided against building projected 3,140-ton type XI U-boats with an aircraft hangar and four guns.Lenton, pp.198&199 Long-range submarines with less impressive deck guns, including Type IXD2 U-boats and United States Navy fleet submarines, evolved through the Second World War; and may be identified as cruiser submarines in comparison to submarines designed for shorter patrols over lesser distances.
Examples
NameNationSurface displacementSubmerged displacementSpeed (Surfaced)GunsTorpedo tubesCrewYearReferenceType U-1391,930 tons2,483 tons2 × 6621916Gray, p.227Type U-1511,512 tons1,875 tons2 × 6561917HMS X12,780 tons3,600 tons4 × 61101923Lenton & Colledge, p.136Type J2,135 tons2,791 tons2 × /40 caliber6801926Watts, p.167Narwhal-class2,730 tons4,050 tons2 × 6"/53 caliber6901928Silverstone, p.186Ettore Fieramosca1,530 tons2,094 tons1 × 12cm (4.7 in) 45 caliber14781929.Surcouf3,250 tons4,304 tons2 × 203mm (8in) 50 caliber10Avalanch Press page on Sucouf says 8 external tubes (2x4), apparently one each 55cm & 40cm (1x4 each), but not how many in the hull.1181934le Masson, p.157Type IXD21,616 tons1,804 tons1 × 6571938K class1,490 tons2,104 tons2 × 10671939 Taylor, p.104Type B2,584 tons3,654 tons1 × /40 caliber61001940Watts, p.1851,461 tons2,136 tons2 × 14851940Kafka & Pepperburg, p.790Type A3,603 tons4,762 tons1 × /40 caliber61001944Watts, p.200
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