单项选择题 Typical marine propulsion plants include（） directly coupled to the vessel’s single large-diameter, fixed-pitch propeller.

单项选择题 Propulsion of the vast majority of contemporary merchant ships (especially containerships and VLCCs) utilizes（） as prime mover.

单项选择题 （）are increasingly used as main engine on merchant vessels, because they have a high Hp/Weight ratio.