A lifeboat is a kind of boat that is used to escape a larger sinking structure such as a cruise ship, commercial vessel, or aircraft that has landed in the water. A lifeboat is intended only for use in case of an emergency. Lifeboats may also be used if the larger structure is not sinking but is experiencing some other sort of disaster such as a fire that has become out of control. Lifeboats are almost always intended for use solely in the event of an emergency.
Lifeboats have traditionally been made out of wood, and some still are. However, these days, it is very common for a lifeboat to be made out of durable plastic or water-resistant tarp. A plastic lifeboat is usually inflatable. Furthermore, they are often referred to as life rafts. Most airplanes, especially commercial airplanes, come equipped with life rafts which are to be used in the event of an emergency water landing.
Because, in an emergency, it would likely take to long to manually inflate a life raft, most of them come equipped with an auto-inflation canister or a mechanical pump. An auto-inflation canister is usually filled with carbon dioxide or nitrogen. Both of these devices are used to quickly inflate the life raft so that passengers of the vessel that is experiencing an emergency can get away quickly.
Military ships also usually have lifeboats on board. In the military, such water vessels are usually referred to as "gigs," "whaleboats," or "dinghies." Offshore platforms used by both the military and civilians are also often equipped with lifeboats or life rafts.
It is important that a lifeboat be quite durable, as the passengers sometimes have to wait quite a while before they are rescued. Many of the boats come equipped with materials that allow passengers to protect themselves from the elements until help arrives. Some even come with a package of materials which may include a first aid kit, oars, flares, mirrors which can be used for signaling, food, potable water, tools to catch drinkable rainwater, and fishing equipment. Some lifeboats are prepared for self-rescue. This means that they have supplies such as navigational equipment and a small engine or sail.
It was shortly after the turn of the 20th century that it became apparent that it was important for ships to be equipped with enough lifeboats to hold all of the passengers on board. In the famed sinking of the RMS Titanic on 15 April 1912, the ship went down with only enough life boats to hold 1,178 people. Unfortunately, the boat was capable of holding well over 3,000 people.