Lifeboat boat Low-poly 3D model

A rescue lifeboat is a boat rescue craft which is used to attend a vessel in distress, or its survivors, to rescue crew and passengers. It can be hand pulled, sail powered or powered by an engine. Lifeboats may be rigid, inflatable or rigid-inflatable combination-hulled vessels. There are generally three types of boat, in-land (used on lakes and rivers), in-shore (used closer to shore) and off-shore (into deeper waters and further out to sea). A rescue lifeboat is a boat designed with specialised features for searching for, rescuing and saving the lives of people in peril at sea or in estuaries.

In the United Kingdom and Ireland rescue lifeboats are typically vessels manned by volunteers, intended for quick dispatch, launch and transit to reach a ship or individuals in trouble at sea. Off-shore boats are referred to as 'All-weather' and generally have a range of 150–250 nautical miles. Characteristics such as capability to withstand heavy weather, fuel capacity, navigation and communication devices carried, vary with size.

A vessel and her crew can be used for operation out to 20 nautical miles (37 km) away from a place of safe refuge, remaining at or on the scene to search for several hours, with fuel reserves sufficient for returning; operating in up to gale force sea conditions; in daylight, fog and darkness. A smaller inshore rescue boat (IRB) or inshore life boat (ILB) and her crew would not be able to withstand (or even survive) these conditions for long.

In countries such as Canada and the United States, the term 'motor lifeboat', or its US military acronym MLB, is used to designate shore-based rescue lifeboats which are generally manned by full-time coast guard service personnel. These vessels stay on standby service rather patrolling in the water, rather like a crew of fire fighters standing by for an alarm. In Canada, some lifeboats are 'co-crewed', meaning that the operator and engineer are full-time personnel while the crew members are trained volunteers. Lifeboats have been modified by the addition of an engine since 1890 which provides more power to get in and out of the swell area inside the surf. They can be launched from shore in any weather and perform rescues further out. Older lifeboats relied on sails and oars which are slower and dependent on wind conditions or manpower. Modern lifeboats generally have electronic devices such as radios and radar to help locate the party in distress and carry medical and food supplies for the survivors.

The Rigid Hulled Inflatable Boat (RHIB) is now seen as the best type of craft for in-shore rescues as they are less likely to be tipped over by the wind or breakers. Specially designed jet rescue boats have also been used successfully. Unlike ordinary pleasure craft these small to medium-sized rescue craft often have a very low freeboard so that victims can be taken aboard without lifting. This means that the boats are designed to operate with water inside the boat hull and rely on flotation tanks rather than hull displacement to stay afloat and upright.

Inflatables (IB)s fell out of general use after the introduction of RIBs during the 1970s. Conditions in New Zealand and other large surf zones was identified and Inflatable Rescue Boats (IRB), small non rigid powered boats, were introduced by New Zealand at Piha Beach and have been put into use in many other countries including Australia and the RNLI in the UK.