单项选择题
A.function when the rudder is amidships
B.relieve excess whip pressure from the hydraulic oil system
C.protect the piping assembly from external rudder shock
D.relieve excessive telemotor pressure
单项选择题 On an electro-hydraulic steering gear, which of the listed devices will keep the rudder from over-traveling the bridge signal?（）
单项选择题 Rudder motion is prevented from exceeding the movement of the steering wheel by the（）
单项选择题 Air trapped in the hydraulic fluid of a steering system may be indicated by（）