1
general::
Easy progress, as in We had a hard time setting up the new computer system but it'll be smooth sailing from here on. The smooth in this idiom alludes to calm waters, free from big waves or roughness, a usage dating from the late 1300s. The transfer to other kinds of easy progress dates from the second half of the 1900s. Also see PLAIN SAILING.
American Heritage Idioms
2
general::
Phrase(s): smooth sailing
Go to clear sailing.
McGrawhill's American Idioms And Phrasal Verbs