1. 栋梁：riderless 没人骑的 | ridge beam 栋梁 | ridge 背脊
2. 屋脊梁木：ridge 屋脊 | ridge beam 屋脊梁木 | ridge board 屋脊板
3. 脊梁：riders 舱内桶装货在顶层的一排 | ridge beam 脊梁 | ridge line 甲板中线