I never tire of looking at boats. In common they displace a volume of water equal to their own weight. The majority of them are designed to move on the surface of the water for the purpose of conveying something or persons from one place to another. Submersibles can float under the surface of the water. Remotely controlled vessels such as those used for underwater explorations or for military purposes may dispense with a crew.
The requirements of function for purpose determines the nature of the hull and the means of propulsion. Within that formula the variety of shape and form devised by their designers is mind-boggling. Considering the category of sailing vessels alone, there are numerous permutations of sail, rigging and hull types. Subdividing sailing vessels into various function types, there are those designed for carrying cargo, although very few today, and for pleasure there are cruising and racing yachts, dinghies and innumerable small wind driven boats.
Therefore, during my Pottering Cruise along the South Coast of England, I inevitably saw many different types of vessels. A selection of photos displayed here can give you an inkling of the variety.