1. These little rascals would eat through a ship’s bottom and very soon sink it.

本句，eat 是不及物动词 “腐蚀”，through 是介词，后面接宾语。意思是“ 把某物腐蚀穿”。由于eat 是不及物动词，所以，宾语不可放在 eat 之后，只能在 through 之后。

2. His curly head was stuffed quite full with the keel.

be stuffed  with：固定搭配。意为“塞满；充满”。

full 在本句是“副词”。意为 “完全地，充分地，到最大程度”，quite 修饰 full ，然后共同修饰 stuffed。

3. Just in the same way as your father does to his boat when she lets in water.

she 指 boat，let in  是“入水，下水”，准备起航。

The sailors repair the ships, which start to let in water. 

水手们修理船只，它们准备入水起航。