What saved Ishmael at the end of Moby DIck?

DG: PLEASE tell me we're not doing fish jokes again!!!!!

Moby Dick destroys the Pequod and kills
the whole crew and then also goes after Ahab and takes him down. Ishmael is saved by the boat's buoy, which floats him up to the surface of the water. He is then saved by another ship "Rachel".

The rescue was a fluke!!!!

I'M SORRY, I COULDN'T HELP MYSELF!!!!!

In the epilogue, Meleville says
..the coffin like-buoy shot lengthwise from the sea, fell over, and floated by my side. Buoyed up by that coffin, for almost one whole day and night, I floated on a soft and dirge-like main.

So I don't know if it was a bouy or the coffin that the carpenter made for Queequeg. (And, yes, the movie with Peck and Basehart showed the coffin.)