Paddle in the context of Lever

A limb (from Old English lim, meaning "body part") is a jointed, muscled appendage of a tetrapod vertebrate animal used for weight-bearing, terrestrial locomotion and physical interaction with other objects. The distalmost portion of a limb is known as its extremity. The limbs' bony endoskeleton, known as the appendicular skeleton, is homologous among all tetrapods, who use their limbs for walking, running and jumping, swimming, climbing, grasping, touching and striking.

All tetrapods have four limbs that are organized into two bilaterally symmetrical pairs, with one pair at each end of the torso, which phylogenetically correspond to the four paired fins (pectoral and pelvic fins) of their fish (sarcopterygian) ancestors. The cranial pair (i.e. closer to the head) of limbs are known as the forelimbs or front legs, and the caudal pair (i.e. closer to the tail or coccyx) are the hindlimbs or back legs. In animals with a more erect bipedal posture (mainly hominid primates, particularly humans), the forelimbs and hindlimbs are often called upper and lower limbs, respectively. The fore-/upper limbs are connected to the thoracic cage via the pectoral/shoulder girdles, and the hind-/lower limbs are connected to the pelvis via the hip joints. Many animals, especially the arboreal species, have prehensile forelimbs adapted for grasping and climbing, while some (mostly primates) can also use hindlimbs for grasping. Some animals (birds and bats) have expanded forelimbs (and sometimes hindlimbs as well) with specialized feathers or membranes to achieve lift and fly. Aquatic and semiaquatic tetrapods usually have limb features (such as webbings) adapted to better provide propulsion in water, while marine mammals and sea turtles have convergently evolved flattened, paddle-like limbs known as flippers.

Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller. Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems.

Human-powered paddles and oars, and later, sails were the first forms of marine propulsion. Rowed galleys, some equipped with sail, played an important early role in early human seafaring and warfare. The first advanced mechanical means of marine propulsion was the marine steam engine, introduced in the early 19th century. During the 20th century it was replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Marine nuclear reactors, which appeared in the 1950s, produce steam to propel warships and icebreakers; commercial application, attempted late that decade, failed to catch on. Electric motors using battery packs have been used for propulsion on submarines and electric boats and have been proposed for energy-efficient propulsion.

Canoeing is an activity which involves paddling a canoe with a single-bladed paddle. In some parts of Europe, canoeing refers to both canoeing and kayaking, with a canoe being called an 'open canoe' or 'Canadian'.

A few of the recreational forms of canoeing are canoe camping and canoe racing. Other forms include a wide range of canoeing on lakes, rivers, oceans, ponds and streams.

Outrigger boats are various watercraft featuring one or more lateral support floats known as outriggers, which are fastened to one or both sides of the main hull. They can range from small dugout canoes to large plank-built vessels. Outrigger boats can also vary in their configuration, from the ancestral double-hull configuration (catamarans), to single-outrigger vessels prevalent in the Pacific Islands and Madagascar, to the double-outrigger vessels (trimarans) prevalent in Island Southeast Asia. They are traditionally fitted with Austronesian sails, like the crab claw sails and tanja sails, but in modern times are often fitted with petrol engines.

Unlike a single-hulled vessel, an outrigger or double-hull vessel generates stability as a result of the distance between its hulls rather than due to the shape of each individual hull. As such, the hulls of outrigger or double-hull boats are typically longer, narrower and more hydrodynamically efficient than those of single-hull vessels. Compared to other types of canoes, smaller outrigger canoes can be quite fast, yet are also capable of being paddled and sailed in rougher water. This paddling technique, however, differs greatly from kayaking or rowing. The paddle, or blade, used by the paddler is single sided, with either a straight or a double-bend shaft.

Rowing is the act of propelling a human-powered watercraft using the sweeping motions of oars to displace water and generate reactional propulsion. Rowing is functionally similar to paddling, but rowing requires oars to be mechanically attached to the boat, and the rower drives the oar like a lever, exerting force in the same direction as the boat's travel; while paddles are completely hand-held and have no attachment to the boat, and are driven like a cantilever, exerting force opposite to the intended direction of the boat.

In some strict terminologies, using oars for propulsion may be termed either "pulling" or "rowing", with different definitions for each. Where these strict terminologies are used, the definitions are reversed depending on the context. On saltwater a "pulling boat" has each person working one oar on one side, alternating port and starboard along the length of the boat; whilst "rowing" means each person operates two oars, one on each side of the boat. On inland waterways, the opposite applies, with "rowing" being where each person in a crew works one oar and "sculling" (especially in sport rowing) involves each participant using a pair of oars. In a maritime setting "sculling" means propelling a boat with a single oar operated over the stern.

A kayak is a small, narrow human-powered watercraft typically propelled by means of a long, double-bladed paddle. The word kayak originates from the Inuktitut word qajaq (IPA: [qajɑq]). In British English, the kayak is also considered to be a kind of canoe.

There are countless different types of kayaks due to the craft being easily adaptable for different environments and purposes. The traditional kayak has an enclosed deck and one or more cockpits, each seating one occupant or kayaker, differentiating the craft from an open-deck canoe. The cockpit is sometimes covered by a spray deck that prevents unwanted entry of water from waves or splashes. Even within these confines, kayaks vary vastly in respect to materials, length, and width, with some kayaks such as the sprint kayak designed to be fast and light, and others such as the whitewater kayak designed to be sturdy and maneuverable.

An oar is an implement used for water-borne propulsion. Oars have a flat blade at one end. Rowers grasp the oar at the other end.

The difference between oars and paddles is that oars are used exclusively for rowing. In rowing the oar is connected to the vessel by means of a pivot point for the oar, either an oarlock, or a thole. The oar is placed in the pivot point with a short portion inside the vessel, and a much larger portion outside. The rower pulls on the short end of the oar, while the long end is in the water. By contrast, paddles are held in both hands by the paddler, and are not attached to the vessel.

Paddling, in regard to waterborne transport, is the act of propelling a human-powered watercraft using at least one hand-held paddle, or paddling directly with the hands (without a paddle) as in traditional paddleboarding (also known as prone paddleboarding). The paddle, which consists of one or two blades joined to a shaft, is also used to steer the vessel via generating a difference in propulsion between the two sides of the watercraft. The paddle is not connected to the boat, unlike in rowing where the oar is attached to the boat.

In paddling sports such as canoeing and kayaking, the characteristics that are most important include "dynamic balance, core stability, pulling power, speed, endurance, stature, and rhythm".

Rowing, often called crew in the United States, is the sport of racing boats using oars. It differs from paddling sports in that rowing oars (called blades in the United Kingdom) are attached to the boat using rowlocks, while paddles are not connected to the boat. Rowing is divided into two disciplines: sculling and sweeping. In sculling, each rower (or oarsman) holds two oars, one in each hand, while in sweeping each rower holds one oar with both hands. There are several boat classes in which athletes may compete, ranging from single sculls, occupied by one person, to shells with eight rowers and a coxswain, called eights. There are a wide variety of course types and formats of racing, but most elite and championship level racing is conducted on calm water courses 2 kilometres (1.2 mi) long with several lanes marked using buoys.

Modern rowing as a competitive sport can be traced to the early 17th century when professional watermen held races (regattas) on the River Thames in London, England. Often prizes were offered by the London Guilds and Livery Companies. Amateur competition began towards the end of the 18th century with the arrival of "boat clubs" at British public schools. Similarly, clubs were formed at colleges within Oxford and Cambridge on the programme for the 1896 games, but racing did not take place due to bad weather. Male rowers have competed since the 1900 Summer Olympics. Women's rowing was added to the Olympic programme in 1976. Today, there are fourteen boat classes which race at the Olympics. In addition, the sport's governing body, the World Rowing Federation, holds the annual World Rowing Championships with twenty-two boat classes.

A spanking paddle is an implement used to strike a person on the buttocks. The act of spanking a person with a paddle is known as "paddling". A paddling may be for punishment (normally of a student at school in the United States), for fun (non-erotic or erotic), or as an initiation or hazing ritual. In the great majority of cases, the paddle is aimed at the recipient's buttocks; less commonly, the back of the thighs might also be targeted. The sensation from the impact of a paddle is a sharp sting that quickly transitions to a deep ache.

The green sea turtle (Chelonia mydas), also known as the green turtle, black sea turtle, and Pacific green turtle, is a species of large sea turtle of the family Cheloniidae. It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans, but it is also found in the Indian Ocean. The common name refers to the usually green fat found beneath its carapace, due to its diet strictly being seagrass, not to the color of its carapace, which is olive to black.

The dorsoventrally flattened body of C. mydas is covered by a large, teardrop-shaped carapace; it has a pair of large, paddle-like flippers. It is usually lightly colored, although in the eastern Pacific populations, parts of the carapace can be almost black. Unlike other members of its family, such as the hawksbill sea turtle, C. mydas is mostly herbivorous. The adults usually inhabit shallow lagoons, feeding mostly on various species of seagrasses. The green sea turtle is the only aquatic turtle species which is herbivorous when fully grown.

Whitewater kayaking is an outdoor adventure sport where paddlers navigate a river in a specially designed kayak. Whitewater kayaking includes several styles: river running, creeking, slalom, playboating, and squirt boating. Each style offers a different way to experience the river environments. Various techniques help paddlers navigate rivers, such as paddle strokes (such as ready position, forward stroke, back stroke, low brace, high brace, forward sweep, back sweep, and duffek/bow rudder), rolling, and boofing. Whitewater kayaking requires much essential equipment to make a “kayaking kit,” such as a whitewater-specific kayak, spray skirt, paddle, helmet, and PFD (personal flotation device).

Paddling on rivers, lakes, and oceans dates back to the Stone Age, with rafts, catamarans, canoes, and kayaks evolving based on the needs of indigenous peoples. After his North American travels, John MacGregor popularized kayaking in Europe in the 19th century, leading to increased leisure paddling during the Industrial Revolution. Innovations by figures like Tom Johnson and Bill Masters further advanced the sport, leading to today's diverse and safety-conscious whitewater kayaking community.

Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a part of the experience.

This activity as an adventure sport has become popular since the 1950s, if not earlier, evolving from individuals paddling 3 metres (9.8 ft) to 4.3 metres (14 ft) rafts with double-bladed paddles or oars to multi-person rafts propelled by single-bladed paddles and steered by a person at the stern, or by the use of oars.

Vallam kali (vaḷḷaṃ kaḷi, literally: boat game), also known as snake boat race, is a traditional boat race held in the Punnamada Lake of Kerala, India. It is a form of canoe racing and uses paddled war canoes. These races typically take place during the monsoon season, from July to September, and are closely associated with the Onam festival.