This statement means that often times you have to clean up others messes to benefit you in the long run.
Ex. Mary answers a math question wrong and it docs your group points, so you have to fix the question and get the remaining questions right to salvage your grade.
Explanation:A mast is a pole that rises vertically from a ship and supports the sails. Really big sailboats have more than one mast. A mast is also another name for flagpole.