A galleon ship with cannons and huge hoisted sails. I used a lot of google image search and wikipedia for this (basis shape and style, materials, sail arts, etc.). The emblems on the sails were created as pixel-art in structure planner.
The huge bow of the ship holds storage rooms, a kitchen, sleeping bunks and - of course :-) - a number of cannons, each with a dispenser ready to fire some fire-charges!

Built in SMP, so you can bet it took a while.