Influenced by the water depth of ship sea trial area, velocity measurement of deep-draft large-scale ship should be shallow-water corrected with proper method.
受实船试航水域水深的影响，对于深吃水的大型船舶航速测量结果必须采用适当的方法进行航速的浅水修正。
2
In most cases, subsequent depth measurements, such as those made during the well completion phase, are corrected to the wellhead datum that is based on drillers depth.