INLAND ONLY A vessel engaged in public safety activities may display an alternately flashing red and yellow light. This special light may be used by a vessel engaged in __________.

Under Inland Navigation Rules, for the condition where 'A vessel engaged in public safety activities may display an alternately flashing red and yellow light. This special light may be used by a vessel engaged in', the correct requirement is: 'patrolling a regatta'. This standard ensures clear navigational intent and collision avoidance.