The opening in the hull of a drillship or other offshore drillingvessel through which drilling equipment passes.
钻井船壳体或者其它海洋钻井船舶的开口部分，钻井设备可以通过其中。
2
It is necessary that drillingvessel is capable of standing still under the action of ocean current wave surge tropical storm and internal wave current in winter.
在冬季的洋流、涌浪以及热带风暴和内波流作用下钻井船有能力保持位置不动是很有必要的。
3
A simple separator vessel used to remove free or entrained gas from fluids circulated in the wellbore, such as mud used during drilling operations.