sentences:  Participation in athletics is, in general, mandatory at the Naval Academy and most Midshipmen not on an intercollegiate team must participate actively in intramural or club sports.There are exceptions for non-athletic Brigade Support Activities such as YP Squadron (a professional surface warfare training activity providing midshipmen the opportunity to earn the Craftmaster Badge) or the Drum and Bugle Corps.Varsity-letter winners wear a specially-issued blue cardigan with a large gold "N" patch affixed.