That's an old shipbuilders' tool, called a 'topping-maul' or 'pin-maul'. They are still used today in repair work on wooden hulls, for driving spikes or bolts into a counterbore in a plank or timber.
Allegedly, the old-timers would have developed the skill to drive a bolt accurately with the 'pin end', but more commonly today, one worker would hold the tool in place with the pin end on the bolt, and another would strike the tool with a sledge.
cheers
Carla