Editing Torpedo boat (section)

==Motor torpedo craft==
[[File:HM CMB No4 (1920).jpg|thumb|right|Captained by Augustus Agar, [[HM Coastal Motor Boat 4|CMB No. 4]] sank a Russian cruiser in Kronstadt harbour.]]
[[File:Mtb 382 FL8592.jpg|thumb|A British World War II [[Vosper 73 ft motor torpedo boat|Vosper 73-ft. motor torpedo boat]]]]
[[File:USS PT-105.jpg|thumb|''[[Patrol torpedo boat PT-105|PT-105]]'', an 80-ft. Elco U.S. Navy [[PT boat]] in World War II]]
[[File:German E-Boat S 204 surrenders at Felixstowe on 13 May 1945.jpg|thumb|The 114-ft. diesel-powered German [[E-boat]]s were considerably larger than most British and American motor torpedo boats.]]

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 (sailing)|planing]] hull designs and were capable of the much higher speed of {{convert|30|to|50|kn|km/h}} under appropriate sea conditions than displacement hulls. The boat could carry two to four torpedoes fired from simple fixed launchers and several [[machine gun]]s.

During the First World War, three junior officers of the [[Harwich Force]] suggested that small motor boats carrying a torpedo might be capable of travelling over the protective minefields and attacking ships of the [[Imperial German Navy]] at anchor in their bases. In 1915, the [[British Admiralty|Admiralty]] produced a Staff Requirement requesting designs for a [[Coastal Motor Boat]] for service in the [[North Sea]]. These boats were expected to have a high speed, making use of the lightweight and powerful petrol engines then available. The speed of the boat when fully loaded was to be at least {{convert|30|kn|km/h}} and sufficient fuel was to be carried to give a considerable radius of action.

They were to be armed in a variety of ways, with torpedoes, [[depth charge]]s or for laying mines. Secondary armament would have been provided by light machine guns, such as the [[Lewis gun]]. The CMBs were designed by [[John I. Thornycroft & Company|Thornycroft]], who had experience in small fast boats. Engines were not proper maritime internal combustion engines (as these were in short supply) but adapted aircraft engines from firms such as [[Sunbeam Motor Car Company|Sunbeam]] and [[D. Napier & Son|Napier]]. A total of 39 such vessels were built.<ref>{{cite web|url=http://www.battleships-cruisers.co.uk/motor_torpedo_boats.htm|title=WW1 numbers and losses of MTB classes}}</ref>

In 1917 Thornycroft produced an enlarged {{convert|60|ft|m|adj=on}} overall version. This allowed a heavier payload, and now two torpedoes could be carried. A mixed warload of a single torpedo and four depth charges could also be carried, the depth charges released from individual cradles over the sides, rather than a stern ramp.<ref name="Banks" >{{cite book|title=I Kept No Diary|author=Air Commodore F. R. Banks|year=1978|pages=29|publisher=Airlife|isbn=0-9504543-9-7}}</ref> Speeds from {{convert|35|-|41|kn|mph km/h}} were possible, depending on the various petrol engines fitted. At least two unexplained losses due to fires in port are thought to have been caused by a build-up of petrol vapour igniting.

[[File:Operation Cerberus-fr.svg|thumb|Admiralty Chart of the [[Channel Dash]], when German destroyers defended a German flotilla against Royal Navy Motor torpedo craft]]
Italian torpedo boats sank the Austrian-Hungarian {{SMS|Wien}} in 1917, and {{SMS|Szent István}} in 1918. During the civil war in Russia, British torpedo boats made raids 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": the British termed them [[E-boat]]s), (Italian) [[MAS (ships)|M.A.S]]. and M.S., [[Soviet Navy]] {{sclass2|G-5|motor torpedo boat|5}} and [[United States|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 {{ship|German battleship|Scharnhorst||2}}, {{ship|German battleship|Gneisenau||2}}, {{ship|German cruiser|Prinz Eugen||2}} and several smaller ships as they passed through the Channel.

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 search and rescue, reconnaissance, ferry and courier work 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 World War II was the cruiser {{HMS|Manchester|1937|6}} which was attacked by two Italian torpedo boats (M.S. 16 and M.S. 22) during [[Operation Pedestal]] on 13 August 1942. It seems that the torpedo that mortally struck ''Manchester'' was launched by M.S. 22 (commanded by {{lang|it|[[Ship-of-the-line lieutenant|Tenente di vascello]]}} Franco Mezzadra) from a distance of about 600 meters.