A museum ship, or sometimes memorial ship, is a ship that has been preserved and converted into a museum open to the public, for educational or memorial purposes. Some are also used for training and recruitment purposes, a use found mostly with the small number of museum ships that are still operational, i.e., capable of regular movement.
There are several hundred museum ships around the world, with around 175 of them organised in the Historic Naval Ships Association though there are also many non-naval museum ships as well, from general merchant ships to tugs and lightships. Many, if not most, museum ships are also associated with a maritime museum.
Despite the long history of sea travel, the ravages of the elements and the expense of maintenance result in the eventual destruction of nearly all ships ever built, often by sinking, usually by being broken up and sold for scrap. Only a few survive, sometimes because of historical significance, but more often due to luck and circumstance. Since an old ship tied up at dockside, without attention, still decays and eventually sinks, the practice of recent years has been to form some sort of preservation society, solicit donations from governments or private individuals, organize volunteer labor from the enthusiasts, and open the restored ship to visitors, usually for a fee.