Yachting refers to recreational sailing or boating, the specific act of sailing or using other water vessels for sporting purposes.
A crew is a body or a class of people who work at a common activity, generally in a structured or hierarchical organization. A location in which a crew works is called a crewyard or a workyard. The word has nautical resonances: the tasks involved in operating a ship, particularly a sailing ship, providing numerous specialities within a ship's crew, often organised with a chain of command. Traditional nautical usage strongly distinguishes officers from crew, though the two groups combined form the ship's company. Members of a crew are often referred to by the title "Crewman".
"Crew" also refers to the sport of rowing, where teams row competitively in racing shells.
"Crew" is used colloquially to refer to a small, tight-knit group of friends or associates engaged in criminal activity. Also used in reference to the traditional "unit" of criminals under the supervision of a caporegime in the American Mafia. However, the term is not specific to (Mafia-affiliated) organized crime.
Crew can refer simply to a group of friends, unrelated to crime or violence.