This is a socketed hafted axe, 2400 years old.
The "socket" is the metal blade on the end, which slots over a peice of timber which in turn is slotted through the head of the haft (handle). The hole in the socket is for a loop or binding of leather or twine to go around the head. This stops the blade coming off.
The large size of the head gives added weight and inertia, plus of course adding strength.
I dont think one of this age, in this condition has ever been found before.
The haft has been worn smooth by the action of hands, and the bottom of the boat still bears scratches from where the axe was slotted under the seat.