MAINSHEETS
Scrabble letter values: M3A1I1N1S1H4E1E1T1S1 = 15
Definition
MAINSHEETS is the plural of MAINSHEET.
noun MAINSHEET: (nautical) a line (rope or chain) that regulates the angle at which a sail is set in relation to the wind.
Synonyms of MAINSHEET: sheet, tack, weather_sheet, shroud