The author explains that there was only wreckage where the back of the ship should have been. The stern must be in the back of the ship because the text says the stern was missing.
Stern as given in the passage is a part of the ship. It is described below.
Explanation:
The stern is the back part of a ship. It is the aft most part of the ship or the boat and in technicality it can be defined as the thing that is built over the presence of the stern post.
It is extended to the vertical towards the sky and until the counter rail from the taffrail onward.
The stern has to lie opposite the bow which is the part of the ship at the front or its foremost.
The both have similar function of making the ship stream lined and moving smoothly on water.
