?梁下纵材,梁下纵梁    under beam girder

?甲板下纵梁,甲板下大梁    under deck girder

?甲板下吨位    under deck tonnage

?不足膨胀    under expansion

?上甲板以下吨位    under upper deck tonnage

?低电压电驿    under voltage relay

?水下装具安置法(钻油)    under water completion

?水中切割    under water cutting

?水下装具    under water fittings

?水下滑道    under water launching ways

?水下计程仪    under water log

?潜航阻力    under water resistance

?水中焊接    under water welding

?航行    under way

?[海上]试航    under way (or sea) trial

?航行灯    under way lamp

?焊珠底龟裂    underbead crack

?过饱和蒸汽    under-cooled (or supersatuated) steam

?[轮齿]过切    undercutting

?甲板下通路    underdeck passage (or way)

?悬吊平衡舵    underhung balanced rudder

?海底研究船    undersea research vehicle

?水中音响定位系统    underwater acoustic positioning system

?水中声学    underwater acoustics

?海底电缆    underwater cable

?潜水舰    underwater craft

?水下检查    underwater inspection

?水下下水台    underwater launching way

?海底管路    underwater pipeline

?水下防护    underwater protection

?出坞    undock (or undocking)

?西班牙国家标准    UNE (= Una Norma Espanola, Spain)

?不顺整    unfairness

?意大利标准协会    UNI (= Unificazione, Italy)

?独立细孔泡沫胶    unicellular foam

?泡沫塑料芯材    unicellular foamed plastic cores

?单向天线    unidirectional antenna

?单向纱束    unidirectional roving

?单向引擎    uniflow engine

?单流驱气    uniflow scavenge

?整流冷凝器    uniflux condenser

?等速流动    uniform flow