单项选择题 For the purpose of training and drills，if reasonable and practicable，rescue boats on an OSV must be launched with their assigned crew（）.

单项选择题 For safety reasons，when assistance towing（）.

单项选择题 For pumping the bilges，a 54 foot long “T-Boat”，which is not a ferry，but is certificated to carry 30 passengers，must be fitted with at least（）.