Sentence:  Every since the age of six Troy Belknap of New York had embarked for Europe every June on the fastest <WSD>steamer</WSD> of one of the most expensive lines. With his family he had descended at the dock from a large noiseless motor, had kissed his father good-bye, turned back to shake hands with the chauffeur (a particular friend), and trotted up the gang-plank behind his mother's maid, [...] 
Meaning of the word marked with <WSD> tags:  A vessel propelled by steam; a steamboat or steamship.