Noun
a life preserver in the form of a ring of buoyant material
Source: WordNetlife-buoy
Henceforth, he uses his coffin for a spare seachest, which is later caulked and pitched to replace the Pequod s life buoy. Source: Internet
Now Queequeg proposes that his superfluous coffin be used as a new life buoy. Source: Internet
The life buoy is thrown, but both sink. Source: Internet