hull down

• (船)远得只见船桅，不见船身；(坦克等)隐蔽得只露出炮塔：

  Having stayed at a small isolated island for about a month, I saw a vessel heave in sight, hull down.

  在一个小孤岛呆了将近一个月后，我终于看见一艘轮船驶入视线，可以看到船的桅杆了。