S38b and S100 E-boats class were German fast attack craft (Schnellboot in German) built for the Kriegsmarine during World War Two. The E-boats (a British designation using the letter E for Enemy) were defined by many naval experts as the best carrying out of their category. Initially these units were called Unterseebot Zerstörer (Hunting Submarine) and Anti-Submmarine Motorboats or Armored Motorboats, as they had an important anti-submarine mission. Later the Kaiserliche Marine (imperial german navy) adopted the designation of Luftschiffmotorenboot (boat with an airship engine) or L-Boote and, therefore, from November 1917, the units became LM-Boote, with the same meaning, but their use, especially in the Baltic Sea and the North Sea, was not particularly successful.