The boat resembles a coffin and has candles lit on the edges that burn with green fire. The ship is only big enough for one person. At the center is a mast that resembles a large crucifix, similar to Mihawk's sword, with black sails and a seat for himself.
This meager craft has no apparent significance, but Mihawk was able to sail the unforgiving seas of the Grand Line on it, which is a testament to his skills.
Not much is known about Mihawk's boat. It was first seen at the Baratie, which is not uncommon as the Baratie is close to the Grand Line. Later, Mihawk arrives with her at an island that Shanks resides, in order to show him that Luffy is now a wanted pirate. In the anime, Mihawk is seen on the boat, looking at Monkey D. Luffy's and Roronoa Zoro's bounty posters, possibly in the Grand Line. The current whereabouts of the boat is unknown.
A model of Coffin Boat is presented in the One Piece Super Ship Collection.