第一近似值 meaning in English

first approximation

From the study results it is showed that turret hole position near the forward of the midship has less effect to the ship girder strength and it is more reasonable using probabilty statistics method to estimate the extreme value of wave bending moment , by which the first approximate value of hull midship section modulus can be determined
研究结果表明：转塔开孔位置在舯前附近对船体总强度影响不大；波浪弯矩极值用概率统计方法估算更为合理；船体结构剖面模数的第一近似值可用波浪弯矩设计极值等来确定。