单项选择题
A.unbalanced rudders
B.balanced rudders
C.contraguide rudders
D.straight rudders
单项选择题 Most covered lifeboats will right themselves after capsizing if the().
单项选择题 In launching a lifeboat,when should the tricing pendants be released?().
单项选择题 In evacuation from a ship,an individual without the option of a survival craft or liferaft should enter the water on the leeward side,except when().