Hello dear friend,
Good question! :) Well, it’s beacuse this specific Icon I posted is Greek Orthodox, and here in Greece St. Nicholas is the Patron Saint of the seamen. There are numerous testimonies of seamen that have seen the Saint in front of them during storms and he has miraculusly saved them from death (a relative of mine have seen him as well, such strong was his faith). That’s why he is driving a ship, because he protects all those who travel at sea :)
God bless you!