A.vernier B.psychrometer C.hygrometer D.stadimeter
A.information or regulatory buoy that has lateral significance B.buoy that is off-station and is marked to warn mariners of its wrong position C.dual purpose marking used where the ICW and other waterways coincide D.buoy that was set in error and will be replaced with a red nun buoy
A.drill stem guide B.guide frame C.drill string frame D.casing guide