Also the part of a crew on a yacht typically responsible for
tactics and
rules interpretations during races. They usually maintain
navigation of the boat, and forecast the weather to assist the
skipper in choosing the fastest track during the race. They are responsible for
MOBOARDs to determine the best angles of attack, and also perform MOBOARDs to determine which angle to the wind produces what boat speed and
speed over ground combination. Finally, their most important responsibility is to maintain the crew's safety by serving as a safety observer, attempting to preclude dangerous situations on the boat.
Usually the afterguard is the lightest member of the boat so that they affect the balance of the boat the least as they move around the cockpit rather than riding the rails for ballast. Typically the afterguard will have racing experience in one of the other crew positions, and thus tends to be one of the senior members of the crew (many times senior to the skipper).