A report on Fin

Fins are used by aquatic animals, such as this orca, to generate thrust and control the subsequent motion

Aquatic animals typically use fins for locomotion
(1) pectoral fins (paired), (2) pelvic fins (paired), (3) dorsal fin, (4) adipose fin, (5) anal fin, (6) caudal (tail) fin

Comparison between A) the swimming fin of a lobe-finned fish and B) the walking leg of a tetrapod. Bones considered to correspond with each other have the same color.

In a parallel but independent evolution, the ancient reptile Ichthyosaurus communis developed fins (or flippers) very similar to fish (or dolphins)

In the 1990s the CIA built a robotic catfish called Charlie to test the feasibility of unmanned underwater vehicles

Thin component or appendage attached to a larger body or structure.

- Fin

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Ray fins on a teleost fish, Hector's lanternfish
(1) pectoral fins (paired), (2) pelvic fins (paired), (3) dorsal fin,
(4) adipose fin, (5) anal fin, (6) caudal (tail) fin

Fish fin

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Lobe-finned fishes, like this coelacanth, have fins that are borne on a fleshy, lobelike, scaly stalk extending from the body. Due to the high number of fins it possesses, the coelacanth has high maneuverability and can orient their bodies in almost any direction in the water.

The haddock, a type of cod, is ray-finned. It has three dorsal and two anal fins

Cartilaginous fishes, like this shark, have fins that are elongated and supported with soft and unsegmented rays named ceratotrichia, filaments of elastic protein resembling the horny keratin in hair and feathers

Similar adaptations for fully aquatic lifestyle are found both in dolphins and ichthyosaurs

In the 1990s, the CIA built a robotic catfish called Charlie, designed to collect underwater intelligence undetected

Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish.

Dorsal fin

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Most fish, like this Prussian carp, have one dorsal fin

The yellowfin tuna also has two dorsal fins

Differences of dorsal fins of orcas between male and female

The dorsal fin of a white shark contains dermal fibers that work "like riggings that stabilize a ship's mast", and stiffen dynamically as the shark swims faster to control roll and yaw.<ref>Lingham‐Soliar T (2005) "Dorsal fin in the white shark, Carcharodon carcharias: A dynamic stabilizer for fast swimming" Journal of Morphology, 263 (1): 1–11. {{doi|10.1002/jmor.10207}} pdf{{dead link|date=September 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Large retractable dorsal fin of the Indo-Pacific sailfish

Various species of Ichthyosaurs displaying different types of dorsal fins

Dorsal fin of a perch showing the basals and radials of the pterygiophore that support the dorsal fin.

Closeup of the dorsal fin of a common dragonet

A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom.

Cetacea

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Infraorder of aquatic mammals that includes whales, dolphins, and porpoises.

Two views of the skeletons of Dorudon atrox, extinct for 40 million years, and Maiacetus inuus, extinct for 47.5 million years, in the swimming position for comparison.

Cetaceans display convergent evolution with fish and aquatic reptiles

Fossil of a Maiacetus (red, beige skull) with fetus (blue, red teeth) shortly before the end of gestation

A whale as depicted by Conrad Gesner, 1587, in Historiae animalium

"Destruction of Leviathan" engraving by Gustave Doré, 1865

Sea World show featuring bottlenose dolphins and false killer whales

Dawn Brancheau doing a show four years before the incident

The fluke is set horizontally on the body, unlike fish, which have vertical tails.

Pelvic fin

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The pelvic fin appears at roughly 21 days post fertilization in zebrafish

Pelvic fin skeleton for Danio rerio, zebrafish.

Gobiids have modified their pelvic fins into adhesive suckers.

Lumpsuckers use their modified pelvic fins to adhere to the substrate.

Pelvic fins or ventral fins are paired fins located on the ventral surface of fish.

Arrow

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Modern arrow with plastic fletchings and nock.

A sideprofile of an Easton Carbon One arrow with a spine of 900, taken with a scanning electron microscope (SEM). The arrow is a bond of two carbon tubes, an inner and an outer tube (black wires). In between both carbon layers, another fiber is used (white fiber). This second fiber is an Mg-Al-Si-fiber. The "white" fiber is twisted around the inner carbon tube. The fibers of the carbon tubes are not twisted, to ensure a maximum of possible mechanical tension of the arrow. The Mg-Al-Si-fiber enhances the flexibility of the arrow. The diameter of a single carbon fiber is approx. 7 µm.

Ancient Greek bronze arrowhead, 4th century BC, from Olynthus, Chalcidice

Modern replicas of various medieval European arrowheads

Straight parabolic fletchings on an arrow.

An arrow is a fin-stabilized projectile launched by a bow.

Fletching

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Plastic fletching (also known as vanes) – this example is parabolic cut with pink hen vanes (the ones put oblique to the bow when nocked on the string) and a green cock (the one – or ones, with even-numbered vanes – put perpendicular to it).

Fletching is the fin-shaped aerodynamic stabilization device attached on arrows, bolts, darts, or javelins, and are typically made from light semi-flexible materials such as feathers or bark.

Pinniped

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Fossil skull cast of Piscophoca sp. from Phocidae

Reconstruction of Archaeodobenus akamatsui family Odobenidae

Male and female South American sea lions, showing sexual dimorphism

Light reflection on an elephant seal eye

Walrus on ice off Alaska. This species has a discontinuous distribution around the Arctic Circle.

Male northern elephant seals fighting for dominance and females

Walrus males are known to use vocalizations to attract mates.

Inuit seal sculptures at the Linden Museum

Captive sea lion at Kobe Oji Zoo Kobe, Japan

Men killing northern fur seals on Saint Paul Island, Alaska, in the mid-1890s

Grey seal on beach occupied by humans near Niechorze, Poland. Pinnipeds and humans may compete for space and resources.

Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals in the clade Pinnipedia.

Grid fin

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Initial design aluminum grid fins on the Falcon 9 launch vehicle, undeployed. February 2015.

Grid fins (here folded against the payload fairing) are part of the launch escape system of Soyuz spacecraft.

Grid fins stowed against the base of an SS-20 ballistic missile

Grid fins on a SpaceX Falcon 9 rocket. They guide the rocket's first stage during landing.

First test of grid fins by SpaceX during a Falcon 9 controlled-descent test on 11 February 2015.

Grid fins (or lattice fins) are a type of flight control surface used on rockets and bombs, sometimes in place of more conventional control surfaces, such as planar fins.

Swimfins, swim fins, diving fins, or flippers are finlike accessories worn on the feet, legs or hands and made from rubber, plastic, carbon fiber or combinations of these materials, to aid movement through the water in water sports activities such as swimming, bodyboarding, bodysurfing, float-tube fishing, kneeboarding, riverboarding, scuba diving, snorkeling, spearfishing, underwater hockey, underwater rugby and various other types of underwater diving.

Surfboard fin

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Hydrofoil mounted at the tail of a surfboard or similar board to improve directional stability and control through foot-steering.

Fins can provide lateral lift opposed to the water and stabilize the board's trajectory, allowing the surfer to control direction by varying their side-to-side weight distribution.