Small and fast, MTBs filled a hundred roles as utilitarian can-do working boats, but what made them a significant threat was that they carried torpedoes that could sink a large ship.
MTBs were made of laminated plywood with wooden frames. This not only made them light and fast, but it also meant that they were not competing for raw materials with other types of weapons, and they could take advantage of the numerous expert furniture makers and carpenters whose skills were of no use in a world of metal and steel.
MTBs were small, shallow drafted, and very fast, with top speeds up to 40 knots or more in calm seas. They ranged from 60 feet to 120 feet in length and were used primarily for inshore coastal patrol work. They carried torpedoes, typically two or four, which they launched in a fan pattern from tubes mounted on their decks.
torpedoed by an American 80-foot Elco PT boat in the Leyte Gulf, 1944
Although the Royal Navy built a small number of steam-powered torpedo boats, most Allied MTBs were powered by V-12 gasoline engines (often derived from aero engines). German MTBs used diesel engines ranging up to V-20s. Putting two, three, or four high-powered engines in a small boat was a recipe for dreadful fuel consumption, and MTBs can fairly be described as floating fuel tanks, with everything else crammed into whatever space the tanks left over. E-Boats, for example, had a standard fuel capacity of 4,000 gallons.
The British and American boats were heavily influenced by the racing boats pioneered by the British designer Hugh Scott-Paine. They had hard chine hulls (a box-like cross-section with a sharp angle between the bottom and sides of the hull) which enabled them to plane on their bow waves, thus greatly reducing the drag of water resistance on the hull, although making them less stable and more vulnerable to rough seas.
German E Boats, in contrast, had soft chines, leaving them lower in the water, but used a technique called the Lürssen effect to force water out from under the hull, thus reducing water resistance. The net effect was that E-Boats sat flatter in the water at speed, making them more seaworthy and less vulnerable to wave action.
Three of the most important classes of torpedo boats were the British Fairmile D, known as a ‘Dog Boat;’ the American Elco PT boat; and the German Schnellboot, known to the Germans as an S-Boot and to the Allies as an E-Boat (E for enemy).
Dog Boats
The Royal Navy’s Coastal Forces began the war with several excellent MTB designs from the British Power Boat Company, Vosper, and Thornycroft, all using similar Scott-Paine inspired hard chine hulls, all in the 60-foot to 70-foot range. These were, however, much smaller than the Kriegsmarine E-Boats they encountered (discussed later in this blog), and the Navy called for a much larger design. This resulted in the 115-foot Fairmile D, almost twice the size of its predecessors.
The wooden hull was built in sections by various furniture manufacturers, transported by road, and assembled for immediate launching. The boat was powered by four 1,250 hp Packard V12 engines giving it a top speed of 30 knots. The D served in the North Sea, the Channel, the Bay of Biscay, and throughout the Mediterranean. Armed as a torpedo boat, it carried four 18-inch torpedoes; armed as a gun boat it had no less than two 6 pounder guns, four 20mm cannons, and four machine guns.
PT Boats
American PT boats (Patrol, Torpedo) were also derived from Scott-Paine design concepts. By far the most numerous and successful were the 80-foot PT boats built by Elco (Electric Launch Company). These boats carried a crew of 17 and were powered by three Packard V12 engines generating 4500hp for a sustained top speed of 41 knots. They were armed with four 21-inch torpedoes, a 20mm cannon, and other smaller weapons. (The hull had over 500,000 screws.)
By far the most famous of these boats was PT109 which was captained by the future president John F Kennedy. It was rammed and sunk by the IJN destroyer Amagiri on August 2nd, 1943. Kennedy, an excellent swimmer, was instrumental in saving the lives of eleven of the crew members.
Unfortunately, PT boats were armed with Mark 8 torpedoes which had numerous problems and greatly detracted from the PT boats’ operational effectiveness in the Pacific. In contrast the Japanese Long Lance torpedoes are generally considered to be the best of any in the war.
The PT boats’ greatest success again enemy shipping occurred on October 23rd, 1944, when PT 137 torpedoed and disabled the Japanese cruiser Abukuma, which was subsequently bombed and sunk by B24 Liberators.
E Boats
German MTBs were called S-Boots (S for Schnell or fast) by the German Kriegsmarine and E-Boats (E for Enemy) by the Allies. At 115 feet they were significantly larger than Allied torpedo boats until Dog Boats were developed. E-Boats used soft chine hulls with extra rudders pointing outward to force water from beneath the hull (the Lürssen effect) which gave them a sustainable top speed of 40 knots while sitting lower and flatter and less vulnerable to rough seas.
They were powered by three massive 134-liter Daimer Db 50123 V20 diesel engines, which had originally been developed to power the immense Hindenburg and Graf Zeppelin airships in the 1930s. In comparison, a typical modern 18-wheeler truck has a 14-liter engine, so an E-Boat had approximately 30 times the cubic capacity!
E Boats were organized in flotillas of 8 boats, typically in a Channel or Baltic port, with responsibility for reconnaissance patrolling, minelaying, and suppressing Allied small craft activities.
The 5th Flotilla based in Cherbourg surprised an American practice landing in Lyme Bay prior to D-Day, and attacked and sank several landing craft, resulting in 800 American deaths. On D-Day itself the 9th Flotilla, also from Cherbourg, came out for a morning patrol and was confronted by the entire 2,000 ship invasion fleet. Discretion being the better part of valor, they fired their torpedoes at extreme range and retreated.
E Boats sank over 350,000 tons of Allied shipping, including shipping sunk by mines laid by E Boats. By comparison PT Boats sank 24,000 tons.
And MAS Boats and Whalebacks
Italian MAS boats (Motoscafo Armato Silurante, torpedo-armed powerboats) and British HSLs (High Speed Launches) are also noteworthy members of the World War II small boat class.
MAS boats scored some notable victories in the Mediterranean, particularly during the intensely fought siege of Malta in 1941 and 1942, including torpedoing the British destroyer HMS Eridge, which was not sunk but never returned to operations.
Regia Marina MAS at speed…
In My Fiction
I wrote about a fictional Whaleback rescue launch in my novel A Slender Thread, which is set in 1942 on the island of Malta in the Mediterranean. That book ends with my protagonist facing an E Boat.
The six-pounder gun with the Molins autoloader which armed many Dog Boats was also mounted in the Mark XVIII ‘Tsetse’ Mosquitos, making them potent gunships. I describe fictional uses of Mark XVIIIs in my books Trial & Tribulation and Dangers & Difficulties.
