Complex sentence: The SS "Robin Moor" was a Hog Islander steamship that sailed under the American flag from 1919 until a sank it on 21 May 1941, before the United States had entered World War II, after allowing the passengers and crew to disembark.
Split into simpler sentences: The SS "Robin Moor" was a Hog Islander steamship that sailed under the American flag from 1919 until May 1941. A, sank the ship on 21 May 1941, before the United States had entered World War II, after allowing the passengers and crew to disembark.