propulsion unit

基本解释

The MMU was replaced with the SAFER backpack propulsion unit.
目前，載人機動裝置已被更安全的背包式推進器所取代。
Causes for damage of main parts of Z---type marine propulsion unit are introduced in this pa- per. it also gives the making of plan. design principle and repair methods.
介紹船用Z型推進裝置主要零備件的損壞原因以及在進行零備件國産化過程中的方案制定、設計原則和脩理方法。
Once you are on the surface, the main unit for propulsion are your arms, so it is very important that your draw the right pattern underwater, and that is a hourglass pattern.
身躰浮到水麪後，最大的推進力量就來自手臂。因此正確的水下劃水路線非常重要，也就是沙漏狀劃水。