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The oceanic whitetip shark, Carcharhinus longimanus, is a large pelagic shark inhabiting tropical and warm temperate seas. Its stocky body is most notable for its long, white-tipped, rounded fins. This aggressive but slow-moving fish dominates feeding frenzies, and is a danger to shipwreck or air crash survivors. Recent studies show steeply declining populations because its large fins are highly valued as the chief ingredient of shark fin soup and, as with other shark species, the whitetip faces mounting fishing pressure throughout its range. The oceanic whitetip is found globally in deep, open water, with a temperature greater than 18 °C (64 °F). It prefers waters between 20 °C (68 °F) and 28 °C (82 °F) and tends to withdraw from areas when temperatures fall below this. They were once extremely common and widely distributed, and still inhabit a wide band around the globe; however, recent studies suggest that their numbers have drastically declined. An analysis of the US pelagic longline logbook data between 1992–2000 (covering the Northwest and Western Central Atlantic) estimated a decline of 70% over that period. The whitetip feeds mainly on pelagic cephalopods and bony fish. However, its diet can be far more varied and less selective—it is known to eat threadfins, stingrays, sea turtles, birds, gastropods, crustaceans, mammalian carrion, and even rubbish dumped from ships. The bony fish it feeds on include lancetfish, oarfish, barracuda, jacks, dolphinfish, marlin, tuna, and mackerel. Its feeding methods include biting into groups of fish and swimming through schools of tuna with an open mouth. When feeding with other species, it becomes aggressive. Peter Benchley, author of Jaws, observed this shark swimming among pilot whales and eating their feces. During World War II, the Nova Scotia, a steamship carrying approximately 1,000 people near South Africa, was sunk by a German submarine. With only 192 survivors, many deaths were attributed to the whitetip. The whitetip poses a minimal threat to bathers or inshore sportsman, but a high risk for humans caught in the open ocean. Although the whitetip is opportunistic and aggressive, and may attack humans for food, divers have swum with this shark repeatedly without incident. Divers are advised to approach the shark only with extreme caution, to not spear fish near this shark and, if the shark comes too close or gets too inquisitive, to get out of the water as soon as possible. [READ THE REST OF THIS ARTICLE]



The M18A1 Claymore is a directional anti-personnel mine used by the U.S. military. It was named after the large Scottish sword by its inventor, Norman A. MacLeod. It is used primarily in ambushes and as an anti-infiltration device against enemy infantry. It is also of some use against unarmored vehicles. The M18A1 Claymore mine consists of a horizontally convex black plastic case (inert training versions are gray), which is vertically concave. The shape was developed through experimentation to deliver the optimum distribution of fragments at 50m range. The case has the words "Front Toward Enemy" embossed on the front surface of the mine. A simple open sight on the top surface is provided for aiming the mine. Two pairs of scissor legs attached to the bottom support the mine and allow it to be aimed vertically. Either side of the sight are fuse wells set at 45 degrees to the vertical. Internally the mine contains a layer of C-4 explosive on top of which is a matrix of approximately seven hundred 1/8 inch diameter steel balls (about as big as #4 birdshot) set into an epoxy resin. When the M18A1 is detonated, the explosion drives the matrix of 700 spherical fragments out of the mine at a velocity of 1,200 m/s, at the same time breaking the matrix into individual fragments. The spherical steel balls are projected in a 60° fan-shaped pattern that is 2m high and 50m wide at a range of 50m. The force of the explosion deforms the relatively soft steel fragments into a shape similar to a .22 rimfire projectile. The Claymore mine is typically deployed in one of three modes: Controlled, Uncontrolled, or Time-delayed. When in use by the U.S. military, the M18A1 Claymore Anti-Personnel Mine is most often command-detonated. Such use is permitted by the Mine Ban Treaty. However, use of Claymore mines in uncontrolled (tripwire) mode is prohibited by the treaty. Because of this uncontrolled mode, it is frequently listed in efforts to ban anti-personnel mines. [READ THE REST OF THIS ARTICLE]





A rubber band gun, often abbreviated to RBG, is a toy gun used to fire one or more rubber bands (or "elastic bands"). RBGs are often used in live-action games such as Assassins, in which they are common, popular and effective toy weapons. They are also common in offices and classrooms. Rubber band guns can be made from ice-cream sticks. The individual sticks are held together by either rubber bands, tape or glue. They can also be cut or carved to the required shape. It is generally limited to pistols and sniper rifles, as only one or two shots can be loaded on most guns, but semi-automatic ice-cream stick guns have been made by determined amateurs. They can also be adapted to fire arrows or other small objects with the rubber bands. In some guns, the handle doubles as a trigger, but using triggers provide much better accuracy. This is the simplest form of rubber band gun. Its firing mechanism consists solely of a clothespin. The gun may have more than one clothespin, thereby allowing more than one band to be fired. The repeater (or revolver) RBG is capable of firing 10 or more rubber bands, semi-automatically. Repeater RBGs are available in a variety of semi-realistic shapes, such as Luger style pistols, rifles, and Tommy guns. The repeater RBG is usually made of wood, and has a plastic firing mechanism, consisting of a toothed wheel onto which the bands are hooked, and a sprung trigger/escapement that releases the wheel by one notch, releasing a rubber band every time the trigger is pulled. A rubber band Gatling gun consists of between 3 and 12 repeater RBGs arranged on a cylindrical "rotor". The rotor rotates and each individual barrel is fired as it reaches the top of its locus. The original, patented (by Surefire Products), tripod-mounted rubber band Gatling gun was featured on the Gadget Show on UK television in March 2007. A twelve-barrel Gatling gun using twelve-shot repeater mechanisms can fire 144 rubber bands automatically. It is fired by manually rotating a crank handle and pulling a firing trigger. [READ THE REST OF THIS ARTICLE]





FV Alaska Ranger was a fishing Factory ship owned and operated by the Fishing Company of Alaska of Seattle, Washington. The ship was constructed in 1973 for use as an oil field service vessel. The ship sank 23 March 2008, after reporting progressive flooding only hours earlier. Sinking and crew rescueThe unexpected and unexplained flooding of the ship meant that the crew had to abandon the vessel at night, into the frigid waters of the Bering Sea. Radio pleas for help were forwarded to a US Coast Guard vessel, which moved toward the area while dispatching helicopters. By the end of the effort, 42 of the 47-person crew had been located and brought safely to shore, most suffering severe hypothermia. The rescue was carried out by a USCG HH-60 Jayhawk which was stationed on Saint Paul Island, AK and a HH-65 Dolphin which was attached to the USCGC Munro, which rescued 20 people, and 22 were rescued by Alaska Ranger’s sister ship FV Alaska Warrior. The ship sank 180 miles west of Dutch Harbor. Aviation Week & Space Technology magazine awarded its 2009 Aviation Week Heroism Award to the U.S. Coast Guard Rescue Team involved in this rescue operation, stating: "The two helicopter crews displayed exceptional risk mitigation and airmanship in fighting time, distance and weather – including snow squalls, a -24°F wind chill, 15 ft seas and 30 kt winds – to rescue survivors. The USCG deems the operation the largest cold-water rescue in its history." According to the United States NTSB, the triggering event in the sinking was the loss of one of the two rudders. This allowed water to pour into the rudder room by way of the 9-inch diameter rudder trunk. The marine architect designed the opening of the rudder trunks to be above the waterline so that water would not enter the rudder room should a rudder fall out. However, United Marine Shipbuilding changed the ship from an oil well service boat to a fishing boat in 1988. The changes raised the waterline 2.5 feet. This put the rudder trunk openings below the water line. The ceiling of the rudder room was only 20 inches above the trunk openings. Flooding of the rudder room should not have sunk the ship since there was a watertight bulkhead. The NTSB can only speculate that the door was left open, the seals or latching dogs failed, or that the holes cut in the bulkhead for refrigeration lines needed for fish processing were not watertight. If the conversion installed a watertight bulkhead between sections of the fish processing area the boat would not have sunk. Whatever the reason, the water flooded the engine room. At some point the water level became high enough to short out the main electrical distribution panel. This caused the loss of electrical power throughout the boat. [READ THE REST OF THIS ARTICLE]





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