"甲板纵骨" can be translated into English as "deck longitudinal" or "deck stringer" (though "deck longitudinal" is more commonly used in technical contexts).
Deck longitudinal: 直接对应中文“甲板纵骨”，指在甲板结构中沿船长方向布置的纵向骨材。
Deck stringer: 虽也表示甲板纵向构件，但在专业术语中，“deck longitudinal”更为精确和常用。