Water castle
A water castle is a castle or stately home whose site is entirely surrounded by water-filled moats (moated castles) or natural waterbodies such as island castles in a river or offshore.
Description
Topographically water castles are a type of lowland castle. The term is mainly found in European-language sources, e.g. under its German names of German: Wasserburg or Wasserschloss, but is also used in English-language sources, usually those referring to European castles of this type. Forde-Johnson describes it as "a castle in which water plays a prominent part in the defences..."
There is a further distinction between:
Water castles, that are protected by artificial water-filled moats or ponds (man-made defences) i.e. a moated castle
Water castles, whose primary means of protection is from river courses or which stand on islands in a lake or natural pond (natural defences). Island castles are an example.
In all cases, water is used as an obstacle to hinder an attacker. That apart, an abundant supply of water was also an advantage during a siege.
Such a castle usually had only one entrance, which was via a drawbridge and that could be raised for protection in the event of an attack. To some extent these water castles had a fortress-like character.