Torpedo boat A torpedo boat is a relatively small and fast naval vessel designed to carry torpedo es into battle . The first designs rammed enemy ships with explosive spar torpedo es , and later designs launched self - propelled Whitehead torpedo es . They were created to counter battleship s and other large , slow and heavily armed ships by speed and agility . A number of inexpensive boats attacking en masse could overwhelm a larger ship ' s ability to fight them off using its large , slow - firing guns . This way an inexpensive fleet of torpedo boats could defend against much larger and more expensive fleets , albeit only in the coastal areas to which their small size and limited fuel load restricted them . The introduction of fast torpedo boats in the late 19th century was a serious concern to navies of the era . In response , navies operating large ships introduced smaller ships to counter the threat . These were essentially similar to the torpedo boats they faced , but mounted a light gun instead of torpedoes . As these designs became more formalized they became known as " torpedo boat destroyers " , and eventually evolved into the modern destroyer . By World War II , American destroyers and destroyer escort s carried relatively small 5 inch guns effective against submarines and boats , but it was their torpedoes which gave them the capability to breach the hull armor of cruisers and battleships like the original torpedo boats . Though they had to sail through a hail of surface fire to get close enough to launch torpedoes , in the Battle Off Samar a task force composed only of small combatants backed by air power used their torpedoes to inflict enough damage to turn back a superior force of cruisers led by a battleship . By World War I powerful engines and planing hull designs were capable of much higher speed than displacement hulls . Relatively small torpedo boats evolved that were 50 to 100 feet ( 15 to 30 m ) in length with maximum speed of 30 to 50 knots ( 56 to 93 km / h ) , carrying two to four torpedoes fired from simple fixed launchers and several machine guns . Italian and British torpedo boats damaged and sank larger vessels in battle . World War II saw the Royal Navy ' s Motor Torpedo Boats ( MTBs ) , Kriegsmarine ' S - Boote ' ( Italian ) M . A . S . and M . S . and U . S . PT boats ( standing for Patrol Torpedo ) PT boats performed reconnaissance , ferry , courier , search & rescue as well as attack and smoke screening duties . Torpedo boats also evolved over time , notably with the addition of guided missile s . Today the class is generally known as " fast attack craft " . American Civil War . The American Civil War saw a number of innovations in naval warfare , including the first torpedo boats , which carried spar torpedo es . In 1861 President Lincoln instituted a naval blockade of Southern ports , which crippled the South ' s efforts to obtain war materials from abroad . The South also lacked the means to construct a naval fleet capable of taking on the Union Navy . One strategy to counter the blockade saw the development of torpedo boats , small fast boats designed to attack the larger capital ship s of the blockading fleet . The " David " class of torpedo boats were steam powered with a partially enclosed hull . They were not true submarines but were " semi - submersible " ; when ballasted , only the smokestack and few inches of the hull were above the water line . On a dark night , and burning smokeless anthracite coal , the torpedo boats were virtually invisible . The " David " s were named after the story of David and Goliath . The and were s . The and represented another class of torpedo boats that were also low built but had open decks and lacked the ballasting tanks found on the " David " s . The Confederate torpedo boats were armed with spar torpedo es . This was a charge of powder in a waterproof case , mounted to the bow of the torpedo boat below the water line on a long spar . The torpedo boat attacked by ramming her intended target , which stuck the torpedo to the target ship by means of a barb on the front of the torpedo . The torpedo boat would back away to a safe distance and detonate the torpedo , usually by means of a long cord attached to a trigger . In general , the Confederate torpedo boats were not very successful . Their low sides made them susceptible to swamping in high seas , and even to having their boiler fires extinguished by spray from their own torpedo explosions . Torpedo misfires ( too early ) and duds were common . In 1864 Union Naval Lieutenant Cushing fitted a steam launch with a spar torpedo to attack the Confederate ironclad . Also the same year the Union launched the , a purpose - built craft with a number of technical innovations including variable ballast for attack operations and an extensible and reloadable torpedo placement spar . The era of self - propelled torpedoes . The first European prototypes of a self - propelled torpedo were created by Giovanni Luppis , an Austrian naval officer from Fiume ( today Rijeka , Croatia ) , a port city of the Austrian Empire . In 1860 , he presented the " salvacoste " ( " coastsaver " ) , a floating weapon , driven by ropes from the land . The project was not taken up by the Navy . Luppis knew Robert Whitehead , an English engineer who was the manager of a marine engineering works in the city , and in 1864 Luppis formed a partnership with him in order to perfect the invention . After a redesign and a number of improvements the result was a submarine weapon , the " Minenschiff " , the first real self - propelled torpedo , officially presented to the Imperial Naval commission on December 21 , 1866 . This device was the fore - runner of the Whitehead torpedo . Late 19th century through the Russo - Japanese War 1904 - 1905 . During the mid - 19th century , the ships of the line were superseded by large steam powered ships with heavy gun armament and heavy armour , named ironclads . Ultimately this line of development lead to the dreadnought class of all - big - gun battleship , starting with . But at the same time , the new weight of armour slowed them , and the huge guns needed to penetrate that armour fired at very slow rates . This allowed for the possibility of a small and fast ship that could attack the battleships , at a much lower cost . The introduction of the torpedo provided a weapon that could cripple , or sink , any battleship . The first boat designed to fire the self - propelled Whitehead torpedo was , completed in 1877 . The French navy followed suit in 1878 with Torpilleur No 1 , launched in 1878 though she had been ordered in 1875 . The Royal Norwegian Navy ' s — the name meaning ' fast ' — was ordered from Thornycroft , England in 1873 , but was not equipped with self - propelled torpedoes until 1879 . The first recorded launch of torpedoes from a torpedo boat ( which itself was launched from a torpedo boat tender ) in an actual battle was by Russian admiral Stepan Makarov on January 16 , 1878 , who used self - propelled Whitehead ' s torpedoes against the during the Russo - Turkish War of 1877 - 78 . The first sinking of an armoured ship by a torpedo boat occurred during the 1891 Chilean Civil War . In the late 19th century , many navies started to build torpedo boats 30 to 50 m in length , armed with up to three torpedo launchers and small guns . They were powered by steam engines and had a maximum speed of 20 to 30 knots ( 37 to 56 km / h ) . They were relatively inexpensive and could be purchased in quantity , allowing mass attacks on fleets of larger ships . The loss of even a squadron of torpedo boats to enemy fire would be more than outweighed by the sinking of a capital ship . The Russo - Japanese War 1904 - 1905 , was the first great war of the 20th century . It was the first massive and practical testing of man ' s new steel battleships , cruisers , his fledgling destroyers ( DDs ) and submarines , and the torpedo boat ( TB ) . During the war the Imperial Russian Navy in addition to their other warships , deployed 86 torpedo boats and launched 27 torpedoes ( from all warships ) in three major campaigns , scoring 5 hits . The Imperial Japanese Navy ( IJN ) , like the Russians , often combined their TBs ( which possessed only hull numbers ) with their torpedo boat destroyer s ( TBDs ) ( often simply referring to them as " destroyers " ) and launched over 270 torpedoes ( counting the opening engagement at Port Arthur on 8 February 1904 ) during the war . The IJN deployed approximately 21 TBs during the conflict , and on 27 May 1905 the Japanese torpedo boat destroyers and TBs launched 16 torpedoes at the battleship , Admiral Rozhestvensky ' s flagship at the battle of Tsushima . Already gunned into a wreck , Admiral Tōgō Heihachirō , the IJN commander , had ordered his torpedo boats to finish off the enemy flagship as he prepared to pursue the remnants of the Russian battle fleet . Of the 16 torpedoes launched by the " TBDs " and " TBs " at the Russia n battleship , only 4 hit their mark , two of those hits were from " torpedo boats " # 72 and # 75 . By evening , the battleship rolled over and sank to the bottom of the Tsushima Straits . By war ' s end , torpedoes launched from warships had sunk 1 battleship , 2 armored cruisers , and 2 destroyers . The remaining over 80 warships would be sunk by guns , mines , scuttling , or shipwreck . Introduction of torpedo boat destroyers . The introduction of the torpedo boat resulted in a flurry of activity in navies around the world , as smaller , quicker - firing guns were added to existing ships to ward off the new threat . In mid - 1880s there were developed torpedo gunboat s , like the Spanish , but they were considered too slow to catch torpedo boats because of the popular belief that the speeds attained by torpedo boats in trial conditions equated to speeds obtainable in service . By 1892 an entirely new class of warship , the torpedo boat destroyer ( " TBDs " ) , was invented to counter them . These ships , which , after the Russo - Japanese War ( 1904 – 1905 ) , became known simply as destroyer s , were basically enlarged torpedo boats , with speed equal to or surpassing the torpedo boats , but were armed with heavier guns that could attack them before they were able to close on the main fleet . Destroyers became so much more useful , having better seaworthiness and greater capabilities than torpedo boats , that they eventually replaced most torpedo boats . However , the London Naval Treaty after World War I limited tonnage of warships , but placed no limits on ships of under 600 tons . The French , Italian , Japanese and German Navies developed torpedo boats around that displacement , 70 to 100 m long , armed with two or three guns of around 100 mm ( 4 in ) and torpedo launchers . For example the Royal Norwegian Navy s were in fact of a torpedo boat size , while the Italian s were closer in size to a destroyer escort . After World War II they were eventually subsumed into the revived corvette classification . The Kriegsmarine torpedo boats were classified " Torpedoboot " with " T " - prefixed hull numbers . The classes designed in the mid - 1930s , such as the Torpedo boat type 35 , had few guns , relying almost entirely upon their torpedoes . This was found to be inadequate in combat , and the result was a " fleet torpedo boat " class ( " Flottentorpedoboot " ) , which were significantly larger , up to 1 , 700 tons , comparable to small destroyers . This class of German boats could be highly effective , as in the action in which the British cruiser was sunk off Brittany by a torpedo salvo launched by the s T23 and T27 . Small torpedo craft . Before World War I steam torpedo boats which were larger and more heavily armed than hitherto were being used . The new internal combustion engine generated much more power for a given weight and size than steam engines , and allowed the development of a new class of small and fast boats . These powerful engines could make use of planing hull designs , such as in the British Coastal Motor Boat , capable of much higher speed under appropriate sea conditions than displacement hulls . The result was a small torpedo boat 50 to 100 feet ( 15 to 30 m ) in length with maximum speed of 30 to 50 knots ( 56 to 93 km / h ) , carrying two to four torpedoes fired from simple fixed launchers and several machine gun s . Italian torpedo boats sank the Austrian - Hungarian in 1917 , and the in 1918 . During the civil war in Russia , British torpedo boats made a raid on Kronstadt harbour damaging two battleships and sinking a cruiser . Such vessels remained useful through World War II . The Royal Navy ' s Motor Torpedo Boat s ( MTBs ) , Kriegsmarine ' S - Boote ' ( " Schnellboot " or " fast - boat " : British termed them E - boat s ) , ( Italian ) M . A . S . and M . S . and U . S . PT boat s ( standing for " Patrol Torpedo " ) were all of this type . A classic fast torpedo boat action was the Channel Dash in February 1942 when German " E - boats " and destroyers defended the flotilla of , , and several smaller ships against Royal Navy MTBs . By World War II torpedo boats were seriously hampered by higher fleet speeds ; although they still had a speed advantage , they could only catch the larger ships by running at very high speeds over very short distances , as demonstrated in the Channel Dash . An even greater threat was the widespread arrival of patrol aircraft , which could hunt down torpedo boats long before they could engage their targets . During World War II United States naval forces employed fast wooden PT boats in the South Pacific in a number of roles in addition to the originally envisioned one of torpedo attack . PT boats performed reconnaissance , ferry , courier , search & rescue as well as attack and smoke screening duties . They took part in fleet actions and they worked in smaller groups and singly to harry enemy supply lines . Late in the Pacific War when large targets became scarce , many PT boats replaced two or all four of their torpedo tubes with additional guns for engaging enemy coastal supply boats and barges , isolating enemy - held islands from supply , reinforcement or evacuation . The most significant military ship sunk by a torpedo boat during WWII was the cruiser which was sunk by two Italian torpedo boat ( M . S . 16 and M . S . 21 ) during Operation " Pedestal " on 13 August 1942 . Fast attack craft today . Boats similar to torpedo boats are still in use , but are armed with long - range anti - ship missile s that can be used at ranges between 30 and 70 km . This reduces the need for high speed chases and gives them much more room to operate in while approaching their targets . Aircraft are a major threat , making the use of boats against any fleet with air cover very risky . The low height of the radar mast makes it difficult to acquire and lock onto a target while maintaining a safe distance . As a result fast attack craft are being replaced for use in naval combat by larger corvette s , which are able to carry radar - guided anti - aircraft missiles for self - defense , and helicopters for over - the - horizon targeting . Although torpedo boats have disappeared from the majority of the world ' s navies , they remained in use until relatively recently in a few specialised areas , most notably in the Baltic . The close confines of the Baltic and ground clutter effectively negated the range benefits of early ASM s . Operating close to shore in conjunction with ground based air cover and radars , and in the case of the Norwegian navy hidden bases cut into fjord sides , torpedo boats remained a cheap and viable deterrent to amphibious attack . Indeed this is still the operational model followed by the Chinese Navy with its for the protection of its coastal and estuarial waters .