Sunday, June 17, 2007

Riverboat

A riverboat is a specialized watercraft (vessel) intended for operating on inland waterways. While a ferryboat is often used to cross a river, a riverboat is used to traverse it, while carrying passengers as well as goods for returns.

Rivers present particular hazards to vessels. They usually have varying water flows that alternately direct to high speed water flows or protruding rock hazards. Changing siltation patterns may cause the rapid manifestation of shoal waters, and often floating or sunken logs and trees (called snags) can endanger the hulls and propulsion of riverboats. Riverboats are usually of thin draft, being wide of beam and rather square in plan, with a short freeboard and high topsides. Riverboats can continue to exist with this type of design as they do not have to survive the high winds or large waves that are seen on large lakes, seas or oceans.
In most nations, riverboats are for tourist attraction. In a few countries, such as China, riverboats offer authentic traveler and consignment transport — something a traveler (as opposed to a tourist) would think about for transport.

Sunday, June 10, 2007

Pleasure craft

A pleasure craft is a boat used for individual leisure or sometimes sporting purpose. Typically such watercrafts are automatic and are used for holidays, for example on a river or canal. Enjoyment craft are normally kept at a marina. They are not essentially intended for speed. They may comprise accommodation for use while moored to the bank. Many narrow boats have been transformed into pleasure craft from their previous use for cargo transport on canals.

Tuesday, June 5, 2007

Dugout

A dugout is a boat which is essentially a hollowed tree trunk; other names for this type of boat are logboat and monoxylon. Monoxylon (Pl: monoxyla) is Greek -- mono (single) + xylon (tree) -- and is frequently used in classic Greek texts.
Dugouts are the oldest boats archaeologists contain found. Within Germany they are called Einbaum (English translation: One tree). Einbaum dug-out boat finds in Germany day back to the limestone Age. The length of bark and hide canoes, these dugout boats were used by American Indians. This is probably because they are made of enormous pieces of wood, which tend to preserve better than, e.g., bark canoes.
Construction of a dugout begins with the collection of a log of appropriate dimensions. Sufficient wood needed to be removed to make the vessel comparatively light in weight and buoyant, yet still strong enough to support the crew and cargo. Particular types of wood were often favorite based on their strength, durability, and weight. The shape of the boat is then fashioned to reduce drag, with sharp ends at the bow and stern.
First the bark is detached from the exterior. Before the exterior of metal tools, dugouts were then hollowed-out using controlled fires. The burnt wood was then detached using an adze. Another method using tools is to chop out parallel notches crossways the interior span of the wood, then split out and remove the wood from between the notches. Once hollowed out, the core was dressed and smoothed out with a knife or adze.
For traveling the rougher waters of the ocean, dugouts can be fitted with outriggers. One or two smaller logs are mounted parallel to the major hull by long poles.