During World War II. The US Navy boats were usually called by their hull classification symbol of "PT" which stood for Patrol Torpedo, hence PT boats. The Royal Navy (RN) referred to them as MTBs and their German enemy's fast torpedo boats as E-boats. MTBs were designed for fast and manouverable travel upon the water with the intent to launch torpedoes at enemy vessels. With next to no armor, the boats relied upon their agility at high speed to avoid being hit by incoming shells.
HMS Cricket, launched in 1906, was the first RN ship which burnt oil. She was initally designated a "Insect" class coastal destroyer, but was later reclassified as torpedo boat. The class were nicknamed "Oily Wads" by RN seamen.
References
"British Motor Torpedo Boat 1939–45" by Angus Konstam, Osprey, 2003, ISBN 1841765007
"Dog Boats at War: A History of the Operations of the Royal Navy d Class Fairmile Motor Torpedo Boats and Motor Gunboats 1939-1945" by L. C. Reynolds and Lord Lewin ,Sutton Pubns Inc, 2000, ISBN 0750924543