单项选择题
A.vessel not under command
B.sailing vessel
C.vessel being towed (manned)
D.vessel being towed (unmanned)
单项选择题 If there is sufficient sea room，alteration of（）may be the most effective action to avoid close-quarters situation.
单项选择题 If there is any doubt as to the proper operation of a radar，which statement is TRUE?（）.
单项选择题 If it becomes necessary for a stand-on vessel to take action to avoid collision，she shall NOT，if possible，（）