单项选择题
A.should be left to port when heading out to sea
B.may be left close aboard on either side
C.is on the north side of a point of interest
D.is marking the preferred channel
单项选择题 Under normal weather and sea conditions when securing a stack of containers with twist locks，lashings are required when the tier exceeds what height? （）
单项选择题 To turn over a liferaft that is floating upside down，you should pull on the（）.
单项选择题 This illustration shows the correct method of securing a（）.