A ship replica is a reconstruction of a no longer existing ship. Replicas can range from authentically reconstructed, fully seaworthy ships, to ships of modern construction that give an impression of a historic vessel. Some replicas may not even be seaworthy, but built for other educational or entertainment purposes.
The term "replica" in this context does not normally include scale models. The term museum ship is used for an old ship that has been preserved and converted into a museum open to the public.
A ship replica may also be a generic replica, one that represents a certain type of ship rather than a particular historic example, like the Kamper Kogge, replicating the Cogs that were used extensively in Northern Europe by the Hanseatic League in the Middle Ages, but where there is little knowledge of specific ships.
Reasons to build a replica include historic research into shipbuilding, national pride, exposition at a museum or entertainment (e.g., for a TV series), and/or education programs for the unemployed. For example, see the project to build a replica of the Continental brigantine Andrew Doria.[1] Apart from building a genuine replica of the ship, sometimes the construction materials, tools and methods can also copied from the ships' original era, as is the case with the replica of the Batavia in Lelystad and the replica of ship of the lineDe Delft[2] in Rotterdam (Delfshaven).
Some generic type replicas such as Thor Heyerdahl's Ra II, qualify as true replicas as these ships were built to investigate the craft and or culture of the original era. That they do not replicate a specific vessel is mainly because no details of such a specific vessel are available.
Some other ships that are modeled after ships of a certain type or era (and are in that sense replicas) do not quality as true replicas. Some ships maybe borderline cases such as the Kanrin Maru, which is actually twice the size of the original, but built following the plans of the original.
Replicas can be temporary, cheap and very simple, such as the replica of a Viking ship that was burnt at the Leixlip Festival.
Notable historic type ships that are not replicas include:
Mircea, which is an almost exact copy of the Gorch Fock. The Mircea was built as a copy because the Gorch Fock was a very successful ship. Thus Mircea was not built as a replica per se, but as a copy for other reasons (i.e. to perform economically, in this case as a training vessel).
Stad Amsterdam also is not a true replica as this is a generic clipper type ship combining the best qualities of clippers of the past with modern materials and technologies.
USS Constitution (1795) is strictly speaking not a replica but the original vessel. However, every part of the ship, except the keel, has been replaced over time. This is a modern version of the philosopher's dilemma concerning replica versus original; known as the Ship of Theseus dilemma.
Another ambiguous case subject to the Ship of Theseus dilemma is the US Brig Niagara. The original was sunk in 1820 for preservation, and the ship has been rebuilt three times since. The third reconstruction was considerably more extensive, and the only parts from the original which were retained are non-structural, leading many authorities to classify her as a replica, rather than a reconstructed original.