Boat
A boat differs from a raft by obtaining its buoyancy by having most of its structure exclude water with a waterproof layer, e.g. the planks of a wooden hull, the hide covering (or tarred canvas) of a currach.
Consequently, except for short river crossings, a raft is not a practical means of transport in colder regions of the world as the users would be at risk of hypothermia.
[2]: 11 The oldest recovered boat in the world, the Pesse canoe, found in the Netherlands, is a dugout made from the hollowed tree trunk of a Pinus sylvestris that was constructed somewhere between 8200 and 7600 BC.
[5][6][7] Hide boats, made from covering a framework with animal skins, could be equally as old as logboats, but such a structure is much less likely to survive in an archaeological context.
[8]: 63, 66–67 Plank-built boats require a level of woodworking technology that was first available in the neolithic with more complex versions only becoming achievable in the Bronze Age.
[10] Other types of large vessels which are traditionally called boats include Great Lakes freighters, riverboats, and ferryboats.
[11] Though large enough to carry their own boats and heavy cargo, these vessels are designed for operation on inland or protected coastal waters.
This is a system by which a steel or iron wire framework is built in the shape of a boat's hull and covered over with cement.
Reinforced with bulkheads and other internal structures it is strong but heavy, easily repaired, and, if sealed properly, will not leak or corrode.
Subsequent layers may be stapled or otherwise mechanically fastened to the previous, or weighted or vacuum bagged to provide compression and stabilization until the resin sets.
An alternative process uses thin sheets of plywood shaped over a disposable male mold, and coated with epoxy.
If weight is added to the boat, the volume of the hull drawn below the waterline will increase to keep the balance above and below the surface equal.
As commercial vessels must be correctly loaded to be safe, and as the sea becomes less buoyant in brackish areas such as the Baltic, the Plimsoll line was introduced to prevent overloading.
Since 1998 all new leisure boats and barges built in Europe between 2.5m and 24m must comply with the EU's Recreational Craft Directive (RCD).
The Directive establishes four categories that permit the allowable wind and wave conditions for vessels in each class:[17] Europe is the main producer of recreational boats (the second production in the world is located in Poland).
