The Navy began to use torpedoes in the 1890s. The first types were designated by the manufacturer's name, and a separate consecutive Mark number series for each manufacturer (there were just two of them - Whitehead and Bliss-Leavitt). In 1913, a common Mark numbering sequence for all torpedoes was started. Existing torpedoes were either redesignated in that common series, or in a short-lived "letter series" as "Type A" through "Type C".

Common Series

Mark Number	Description
MARK 1	21-inch, 1500 lb; for surface ships
MARK 2	21-inch, 1500 lb; for surface ships; improved MK 1 with contra-rotating propellers
MARK 3	21-inch, 1500 lb; for surface ships; improved MK 2 with increased range
MARK 4	17.7-inch, 1500 lb; for submarines
MARK 5	17.7-inch, 1450 lb; for destroyers and torpedo boats; first variable-speed torpedo (3 pre-load settings)
MARK 6	17.7-inch, 1800 lb; for destroyers, cruisers and submarines (E to H Class)
MARK 7	17.7-inch, 1630 lb; for submarines (K, O and R Class)
MARK 8	21-inch, 2760 lb (MOD 0), 3180 lb (MOD 8); for destroyers
MARK 9	21-inch, 2015 lb; for battleships and submarines (R and S Class)
MARK 10	21-inch, 2215 lb; for submarines
MARK 11	21-inch, 3510 lb; for destroyers and cruisers; three pre-launch speed settings
MARK 12	21-inch, 3500 lb; for destroyers and cruisers; MK 11 with lower high-speed setting for improved reliability
MARK 13	22.5-inch, 1950 lb (MOD 0), 2220 lb (MOD 10); standard aircraft torpedo of WW 2
MARK 14	21-inch, 3000 lb; standard submarine torpedo of WW 2
MARK 15	21-inch, 3440 lb (MOD 0), 3840 lb (MOD 3); for destroyers and cruisers (Atlanta Class); standard destroyer torpedo of WW 2
MARK 16	21-inch, 3900 lb; for submarines
MARK 17	21-inch, 4800 lb; development of MK 16 for destroyers
MARK 18	21-inch, 3040 lb; for submarines; captured German G7e design built in the U.S.
MARK 19	21-inch, 3240 lb; development of MK 18, cancelled in favor of MK 26
MARK 20	21-inch, 3100 lb; development of MK 18, cancelled in favor of MK 26
MARK 21	22.5-inch, 2130 lb; designed as homing torpedo for aircraft, but eventually used as payload of AUM-N-2 Petrel missile
MARK 22	21-inch, 3060 lb; homing torpedo for submarines; prototypes only, cancelled in favor of MK 35
MARK 23	21-inch, 3260 lb; for submarines; as MK 14, but without the low-speed setting
MARK 24	19 inch, 680 lb; homing torpedo for aircraft, also known as Fido and originally designated MK 24 Mine
MARK 25	22.5-inch, 2310 lb; for aircraft; intended replacement for MK 13, but not produced
MARK 26	21-inch, 3200 lb; for submarines; cancelled in favor of MK 16
MARK 27	19-inch, 720 lb; variant of MK 24 for submarines
MARK 28	21-inch, 2800 lb; homing torpedo for submarines; development of MK 18
MARK 29	21-inch, 3200 lb; homing torpedo for submarines; development of MK 18, prototypes only
MARK 30	21-inch, 3200 lb; wake-following homing torpedo for submarines; not produced
MARK 31	21-inch, 2800 lb; development of MK 18, cancelled
MARK 32	19-inch, 700 lb; homing torpedo (first active acoustic) for surface ships; also known as MK 32 Mine
MARK 33	21-inch, 1770 lb; homing torpedo for aircraft and submarines; not produced
MARK 34	21-inch, 1150 lb; homing torpedo for aircraft; improved MK 24 with magnetostrictive hydrophones and separate search/attack speeds; initially designated MK 44 Mine
MARK 35	21-inch, 1770 lb; active/passive homing torpedo for surface ships and submarines; derived from MK 24, MK 32 and MK 33 designs
MARK 36	21-inch, 4000 lb; for submarines; abandoned in favor of MK 42
MARK 37	19-inch, 1430 lb (MOD 0/3), 1690 lb (MOD 1/2); active/passive homing (MOD 0/3) or wire-guided (MOD 1/2) torpedo for all ASW vessels
MARK 38	21-inch, 3000 lb; homing torpedo for submarines; cancelled in favor of MK 37
MARK 39	21-inch, 1275 lb; wire-guided torpedo for submarines
MARK 40	12.75-inch, 1250 lb; for aircraft and missiles; cancelled
MARK 41	21-inch, 1330 lb; active/passive homing torpedo for aircraft; derivative of MK 35, abandoned in favor of MK 43
MARK 42	21-inch, 4000 lb; for submarines; last non-homing USN torpedo, not produced
MARK 43	12.75-inch, 280 lb (MOD 1), 265 lb (MOD 3); active homing torpedo for aircraft and surface ships
MARK 44	12.75-inch, 425 lb; active homing torpedo for missiles; used as payload of RUR-5 ASROC
MARK 45	19-inch, 2330 lb; wire-guided nuclear armed (MK-34 Nuclear Warhead) torpedo for submarines; also known as ASTOR
MARK 46	12.75-inch, 570 lb; active homing torpedo for aircraft, surface ships and missiles (used in RUR-5 ASROC MOD 4, and in RUM-139A/B VL-ASROC); developed through MOD 1 to MOD 6; NATO standard anti-submarine torpedo
MARK 47	Proposed anti-ship torpedo for submarines; cancelled in favor of MK 48
MARK 48	21-inch, 3440 lb; active/passive homing and/or wire-guided torpedo for submarines; MOD 5 and MOD 6 known as MK 48 ADCAP (Advanced Capabilities), with improved guidance electronics, higher speed and longer range; MK 48 ADCAP is standard U.S. Navy submarine torpedo
MARK 49	Number reserved (possibly for a potential MK 48 successor), but not taken up
MARK 50	12.75-inch, 750 lb; active/passive homing torpedo for aircraft and surface ships; known as Advanced Light Weight Torpedo (ALWT) Barracuda, built by Honeywell
MARK 51	12.75-inch; unsuccessful Advanced Light Weight Torpedo (ALWT) contender by McDonnell Douglas
(52...53)	(No information)
MARK 54	12.75-inch, 610 lb; active/passive homing torpedo for aircraft, surface ships and missiles (used in RUM-139C VL-ASROC); originally known as LHT (Lightweight Hybrid Torpedo), built by Raytheon

Navy Nomenclature System

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Last Updated: 7 May 2024