Boat

A boat is an item and vehicle entity. Boats float and move easily on water, and can be ridden, so they allow fast transportation on the ocean or any large area of water; however they are quite fragile and easily destroyed by running aground. Boats can be pushed around by water currents, allowing automatic transportation and boat storage, and the use of boats as mechanism components. Notch said that he'll try to make "fancy huge customizable boats."

Once crafted, a boat may be placed anywhere in water, or on land by right-clicking, but cannot be recovered once placed. You can also place a boat in lava, but if you try to ride it the boat will break and you will fall into the lava and start taking damage.

Boats being pushed along snow will clear the ground of snow.

Riding boats
Like minecarts, a boat may be right-clicked to enter or exit. Boats can be entered from any direction, including below (which is useful for getting to the surface slightly quicker after diving).

Boats move according to the player's control or water currents. Boats move significantly faster than a player can walk on land or water, but are slower than minecarts. If on land, a boat may still be controlled but extremely slowly.

Boats are controlled by the player's movement keys: they will accelerate slowly in the same direction the player would move if they were not in the boat. Boats also turn to always face in the direction of movement, turning you with them. For example, pressing the forward and right keys, or pressing the forward key while you face slightly to the right, will result in moving in a circle as the boat swings to the right, continuously changing your “push” direction. When moving fast enough, there will be "water spray" visual effect representing the bow wake.

If you move through an area with only 1 block of air between the water and ceiling, you will take suffocation damage, but can still move anywhere the boat can.

If you try to sneak while on a boat, the boat will not break on impact while traveling at high speed. It's also recommended to bring a few spares if you are planning any kind of lengthy boat journey. There is a much smaller chance of a boat breaking when it impacts with wool; making wool a good material for building docks.

Boat physics
Boats are entities. Boats suck; they can be pushed around slowly on solid blocks, are easily pushed around by water currents, and always face the direction they last moved.

If a boat runs into another entity such as a player, another boat, or a mob, it will bounce off and change direction; running into a block will merely stop movement (if the boat does not break).

Boats are fragile; they take damage by being hit or crashing into blocks. After taking enough damage over a short interval, the boat will break, dropping 3 Wooden Planks and 2 Sticks. Since they do not drop boat resources, boats cannot be picked up and reused like minecarts.

If you crash a boat into another boat, the boat being ridden will be destroyed while the other one will just bump away. Boats do not break when running into Soul Sand at water level, because Soul Sand has a lower top surface so that the boat merely runs aground rather than crashing, so it is useful to make docks and harbors out of soul sand.

Doors can be used to control the movement of boats, such as blocking them into docks or preventing them from following a current until the door is opened. This technique is often used to build boat dispensers.

Whilst boats used to float upwards in any type of water, flowing or not, downwards flowing water will now cause them to become stuck on the bottom, making many water-elevator devices useless and risking the player drowning. A water elevator constructed solely of source blocks still works, a bit slower than water elevators before.

Canal
Canals, consisting of a series of trenches dug on land filled with flowing water, are a possible method of transportation across large distances using boats. A canal transportation system is more time-consuming to construct, but more energy-efficient than a rail transportation system. Double doors, fence gates, ladders, pressure plates, and sugar canes can be used as consecutive locks on the canal to control the direction of the flow of water in a canal to construct a flowing fully horizontal waterway. Locks can also be used for boat lifts (Water Elevator or Water Ladder) between different elevations of water. (For real life examples, see Wikipedia's canal, lock (water transport), and boat lift.)

It is also possible to construct a canal with still water by strategically placing water in the pattern of a chessboard. This makes for faster transportation, however a longer construction time as more water is needed.

History
Boats first appeared in the Seecret Friday Update 5 of Alpha. As of Beta Version 1.8, it is possible to score a Critical Hit against a Boat. As of the Beta 1.6.6 update, crashing into soul sand on a boat will kill the player, but keep the boat intact.

Bugs

 * When entering a portal while sitting in a boat, the game will crash.
 * In SMP, there are sometimes problems exiting the boat where the server will keep putting you on top of the boat while you try to get off. This continues after an undetermined amount of time, or your boat gets destroyed.
 * In SMP, the "water spray" effect will not appear.
 * There is a glitch where if you place a boat on top of glass, get in, and break the boat you will fall through the glass taking 1 heart of damage
 * Boats at the top of the world will be invisible.
 * When placing a boat on ground, not water, the graphic for splashing water still appears.
 * If the player exits the game while on a boat, the boat will be far away and the player will fall into the water upon reloading.
 * When entering a boat while holding a food item, the action of right-clicking the boat will count simultaneously as the action to eat the food.
 * When entering/leaving a boat while holding a bow, the action of right-clicking will also fire an arrow (if the player is carrying arrows).
 * If you are holding a boat and try to open a door, the boat will be placed on top of the door.
 * Similar to above, crashing into any animal in a boat can kill the player, keeping the boat intact.
 * Similar to both of the above two items, running aground on slabs will inflict some amount of falling damage. The damage seems to be much worse the longer you've been in the boat. (Perhaps due to the bobbing motion at sea being counted as 'falling' distance, and caching it all in at once.)
 * When in 3rd person view, it is possible to see underwater by swinging the camera underwater while in a boat.
 * When right-clicking on an existing boat in the water with a boat in your hand, you will enter the boat and be propelled through the water at a high rate of speed.
 * If a boat is placed onto a rail the boat will stay inside of the block above the rail until the boat takes enough damage.

Gallery

 * A video of boat riding
 * A video of a simple boat elevator for transportation
 * A video of a boat placed on lava