A pirate ship of the wind sail variety.A boat is a transportation device that moves along water either by raw man power, such as rowing or peddling, wind powered, or by motor, usually with a propeller. By naval definition, a boat is a watercraft that is small enough to be brought aboard another vessel. The largel vessel is known as a
ship . However this definition is not always strict as there are numerous
seavessels that are considered to be boats.
These include:
Riverboats, ferry boats, even
submarines, despite the fact that it is large and travels under the surface of the water.
How Does It float?
Boats are able to float because the weight of the boat is roughly equal to the amount of water that it displaces when it rests on top of the water. This concept is known as buoyancy. Even if the materials that are used in the vessel's construction are heavier than the water the vessel will still float. This is because the heavy materials are only used in the construction of the outer edges of the craft. The interior is empty, and therefore is filled with air which contributes to the overall volume of the watercraft, but does not add to its total weight.
A light motor boat resting in the water. Displacement at work!To sum up, in order for a boat to remain afloat the weight of the boat including all passengers and cargo must be so equal to the density of the water that is being displaced. If more cargo is added to the vessel, then the boat will sink slightly to compensate for the increase in density. It essentially is as if the boat is taking the place of the water, not merely resting on top of it.
History
Boats are an ancient method of transportation. Evidence suggests that the oldest boats used were originally crafted from a log or a tree. The oldest boats on record are believed to be somewhere between 7,000 and 9,000 years old. Since the start, boats have been used for economic trade and for military conquest or colonization.
Construction
Throughout history boats have been constructed mostly out of natural materials, wood in particular. However as technology has advanced, boat building technology has become vastly improved. Most small watercraft are now made out a steal or iron fram, but are often still covered in wood. Some boats are also made out of plastic or light weight metals such as aluminum.
Propulsion
There are three common types of propulsion used to move a boat:
- Used in row boats, paddle boats etc...
Paddle Boat- Propelled by paddling with your feet!
WindPower
- Commonly used in sailing
MotorPowered
- Diesel and gas
- Electric
- Paddle Wheel
- Nuclear (submarines)
- Water Jet propulsion
- Air fans
Common Types of Boats
Rowboat in action! - Rowboat
- Canoe
- Kayak
- Lifeboat
- Schooner
- Sailboat
- Raft
- Barge
- Skiff Twin Wooden Canoes.
- Submarine
Submarine
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