"its Silva orienteering compass to Swedish orienteers, outdoorsmen, and army officers. The liquid compass is a design in which the magnetized needle or card is damped by fluid to protect against excessive swing or wobble, improving readability while reducing wear. A rudimentary working model of a liquid compass was introduced by Sir Edmund Halley at a meeting of the Royal Society in 1690. However, as early liquid compasses were fairly cumbersome and heavy, and subject to damage, their main advantage was aboard ship. Protected in a binnacle and normally gimbal-mounted, the liquid inside the compass housing effectively damped shock and"
"compass as it is termed in nautical use, has been used by small-boat or inshore sailors since at least the 1920s to keep a running course or to record precise bearings to landmarks on shore in order to determine position via the resection technique. Instead of a magnetized needle or disc, most hand bearing compasses feature liquid damping with a ""floating card"" design (a magnetized, degreed float or dial atop a jeweled pivot bearing). Equipped with a viewing prism, the hand bearing compass allows instant reading of forward bearings from the user to an object or vessel, and some provide"
"Binnacle A binnacle is a waist-high case or stand on the deck of a ship, generally mounted in front of the helmsman, in which navigational instruments are placed for easy and quick reference as well as to protect the delicate instruments. Its traditional purpose was to hold the ship's magnetic compass, mounted in gimbals to keep it level while the ship pitched and rolled. A binnacle may be subdivided into sections and its contents typically include one or more compasses and an oil lamp or other light source. Other devices such as a sand timer for estimating speed may have"
"Casing (submarine) The casing of a submarine is a light metal structure, usually incorporating a deck, built over the upper surface of the vessel's pressure hull. The pressure hull of a submarine is usually cylindrical and possesses a low freeboard when in the water, which makes walking on the hull when on the surface dangerous in high seas or rough weather. The casing provides a flat and therefore safer platform for personnel to walk on. The casing is outside the pressure hull and free-flooding so is usually perforated with numerous holes, allowing water to enter and trapped air to escape"
"flight. Pilots must compensate for such errors when using the magnetic compass. Most of the errors inherent in the heading indications of a magnetic compass are related to the compass' construction. An aircraft compass consists of an inverted bowl with a magnetized bar attached. The bowl is balanced on a low friction pin. The bowl and pin assembly is enclosed in a case filled with non-acidic kerosene. The magnetized bar tends to orient the assembly with the local geomagnetic field. The bar turns the visible bowl of the compass. The outside surface of the bowl includes markings to indicate a"
"or in poor light. As the compass fill liquid is noncompressible under pressure, many ordinary liquid-filled compasses will operate accurately underwater to considerable depths. Many modern compasses incorporate a baseplate and protractor tool, and are referred to variously as ""orienteering"", ""baseplate"", ""map compass"" or ""protractor"" designs. This type of compass uses a separate magnetized needle inside a rotating capsule, an orienting ""box"" or gate for aligning the needle with magnetic north, a transparent base containing map orienting lines, and a bezel (outer dial) marked in degrees or other units of angular measurement. The capsule is mounted in a transparent baseplate"
"elaboration of the pelorus points led to the modern compass rose. Pelorus (instrument) In marine navigation, a pelorus is a reference tool for maintaining bearing of a vessel at sea. It is a ""dumb compass"" without a directive element, suitably mounted and provided with vanes to permit observation of relative bearings. In appearance and use, a pelorus resembles a compass or compass repeater, with sighting vanes or a sighting telescope attached, but it has no directive properties. That is, it remains at any ""relative"" direction to which it is set. It is generally used by setting 000° at the lubber's"
"that the difficulty of locating satellite by signals from underwater at present is not capable of being overcome by existing technology. The typical diving compass is made from a card with graduation in degrees, mounted on a pivot in a transparent housing filled with fluid which damps the movement and prevents pressure collapse of the housing. It may be wrist mounted, console mounted or carried some other way. It is desirable that the compass can operate accurately at significant tilt angles without sticking. On the card there is a magnet which will interact with the ambient magnetic field so as"
"maritime merchants and sailors acquired the compass at some point and used it for navigation. The dry mariner's compass consists of three elements: A freely pivoting needle on a pin enclosed in a little box with a glass cover and a wind rose, whereby ""the wind rose or compass card is attached to a magnetized needle in such a manner that when placed on a pivot in a box fastened in line with the keel of the ship the card would turn as the ship changed direction, indicating always what course the ship was on"". Later, compasses were often fitted"
"face of the ship's compass. Eight concentric rings are inscribed on the compass rose. Each ring has one peg hole at each point of the compass. Eight pegs are attached to the centre of the compass rose with strings. The bottom part is for recording speed. It has four rows of holes. Each column represents a certain speed, measured in knots. Three more columns to the right give fractional knots: , , and . Eight pegs are attached to this part of the board. Each half-hour during the watch, a crew member inserted a peg in the top part of"
"has a half-life of only about 12 years, so a compass that contains 120 mCi of tritium when new will contain only 60 when it is 12 years old, 30 when it is 24 years old, and so on. Consequently, the illumination of the display will fade. Mariners' compasses can have two or more magnets permanently attached to a compass card, which moves freely on a pivot. A ""lubber line"", which can be a marking on the compass bowl or a small fixed needle, indicates the ship's heading on the compass card. Traditionally the card is divided into thirty-two points"
"their accuracy. Compasses are particularly difficult to use accurately in or near trucks, cars or other mechanized vehicles even when corrected for deviation by the use of built-in magnets or other devices. Large amounts of ferrous metal combined with the on-and-off electrical fields caused by the vehicle's ignition and charging systems generally result in significant compass errors. At sea, a ship's compass must also be corrected for errors, called deviation, caused by iron and steel in its structure and equipment. The ship is ""swung"", that is rotated about a fixed point while its heading is noted by alignment with fixed"
"(known as ""rhumbs""), although modern compasses are marked in degrees rather than cardinal points. The glass-covered box (or bowl) contains a suspended gimbal within a binnacle. This preserves the horizontal position. A thumb compass is a type of compass commonly used in orienteering, a sport in which map reading and terrain association are paramount. Consequently, most thumb compasses have minimal or no degree markings at all, and are normally used only to orient the map to magnetic north. An oversized rectangular needle or north indicator aids visibility. Thumb compasses are also often transparent so that an orienteer can hold a"
"the reciprocal bearing as well. Modern examples of marine hand bearing compasses include the ""Suunto KB-14"" and ""KB-77"", and the ""Plastimo Iris 50"". These compasses frequently have battery-illuminated or photoluminescent degree dials for use in low light or darkness. Hand compass A hand compass (also hand bearing compass or sighting compass) is a compact magnetic compass capable of one-hand use and fitted with a sighting device to record a precise bearing or azimuth to a given target or to determine a location. Hand or sighting compasses include instruments with simple notch-and-post alignment (""gunsights""), prismatic sights, direct or lensatic sights, and"
"easily, eliminating any buoyancy contributed by the casing and allowing the submarine to submerge with as little delay as possible. Casings have been eliminated since the end of World War II as the flow of water through the numerous flood-holes creates noise that may be detected by an enemy using passive sonar, as well as causing hydrodynamic drag. Casing (submarine) The casing of a submarine is a light metal structure, usually incorporating a deck, built over the upper surface of the vessel's pressure hull. The pressure hull of a submarine is usually cylindrical and possesses a low freeboard when in"
"Pelorus (instrument) In marine navigation, a pelorus is a reference tool for maintaining bearing of a vessel at sea. It is a ""dumb compass"" without a directive element, suitably mounted and provided with vanes to permit observation of relative bearings. In appearance and use, a pelorus resembles a compass or compass repeater, with sighting vanes or a sighting telescope attached, but it has no directive properties. That is, it remains at any ""relative"" direction to which it is set. It is generally used by setting 000° at the lubber's line. Relative bearings are then observed. They can be converted to"
"Sail (submarine) In naval parlance, the sail (American usage) or fin (European/Commonwealth usage) of a submarine is the tower-like structure found on the dorsal (topside) surface of submarines. Submarine sails once housed the conning tower (command and communications data center), the periscope(s), radar and communications masts (antenna), though most of these functions have now been relocated to the hull proper (and so the sail is no longer considered a ""conning tower""). In the US Navy, the structure is frequently called a fairwater, and diving planes mounted on it are called fairwater planes. When above the water's surface, the sail serves"
"on Dante's ""Divine Comedy"" from 1380, while an earlier source refers to a portable compass in a box (1318), supporting the notion that the dry compass was known in Europe by then. A ""bearing compass"" is a magnetic compass mounted in such a way that it allows the taking of bearings of objects by aligning them with the lubber line of the bearing compass. A ""surveyor's compass"" is a specialized compass made to accurately measure heading of landmarks and measure horizontal angles to help with map making. These were already in common use by the early 18th century and are"
"Heading (navigation) In navigation, the heading of a vessel or aircraft is the compass direction in which the craft's bow or nose is pointed. This may not necessarily be the direction that the vehicle actually travels, which is known as its ""course"" or ""track"". Any difference between the heading and course is due to the motion of the underlying medium, the air or water, or other effects like skidding or slipping. The difference is known as the ""drift"", and can be determined by the ""navigational triangle"". Heading is typically based on compass directions, so 0° (or 360°) indicates a direction"
"Compass A compass is an instrument used for navigation and orientation that shows direction relative to the geographic cardinal directions (or points). Usually, a diagram called a compass rose shows the directions north, south, east, and west on the compass face as abbreviated initials. When the compass is used, the rose can be aligned with the corresponding geographic directions; for example, the ""N"" mark on the rose points northward. Compasses often display markings for angles in degrees in addition to (or sometimes instead of) the rose. North corresponds to 0°, and the angles increase clockwise, so east is 90° degrees,"
"Azimuth compass An azimuth compass (or azimuthal compass) is a nautical instrument used to measure the magnetic azimuth, the angle of the arc on the horizon between the direction of the sun or some other celestial object and the magnetic north. This can be compared to the true azimuth obtained by astronomical observation to determine the magnetic declination, the amount by which the reading of a ship's compass must be adjusted to obtain an accurate reading. Azimuth compasses were important in the period before development of the reliable chronometers needed to determine a vessel's exact position from astronomical observations. In"
"be moved around the ship, and it was soon observed that the bearing could vary from one part of the ship to another. The explorer Joao de Castro was the first to report such an inconsistency, in 1538, and attributed it to the ship's gun. Many other objects were found to be sources of deviation in ships, including iron particles in brass compass bowls; iron nails in a wooden compass box or binnacle; and metal parts of clothing. The two steering compasses themselves could interfere with each other if they were set too close together. The ""bearing compass"" was eventually"
"Caboose (ship's galley) Caboose (also ""camboose, coboose, cubboos"" derived from the Dutch ""kombuis"") is a term used for a small ship's kitchen, i.e. galley, located on an open deck. At one time a ""caboose"" related to a smaller kitchen aboard a merchantman, while aboard a warship it was called a ""galley"". William Falconer's 1780 ""A Universal Dictionary of the Marine"" describes a caboose thus: ""a sort of box or house to cover the chimney of some merchant-ships. It somewhat resembles a sentry-box, and generally stands against the barricade on the fore part of the quarter-deck"". Sometimes the caboose was portable."
"Flinders bar A Flinders bar is a vertical soft iron bar placed in a tube on the fore side of a compass binnacle. The Flinders bar is used to counteract the vertical magnetism inherent within a ship and is usually calibrated as part of the process known as ""swinging the compass"", where deviations caused by this inherent magnetism are negated by the use of horizontal (or quadrantal) correctors. Where the deviation from a compass point cannot be counteracted through the use of Flinders bar, Kelvin's balls, Heeling error magnets and Horizontal magnets, a deviation card, or graph, is produced. This"
"the compass. To compensate for the induced magnetization, two magnetically soft iron spheres are placed on side arms. However, because the magnetic ""signature"" of every ship changes slowly with location, and with time, it is necessary to adjust the compensating magnets, periodically, to keep the deviation errors to a practical minimum. Magnetic compass adjustment and correction is one of the subjects in the examination curriculum for a shipmaster's certificate of competency. The sources of magnetic deviation vary from compass to compass or vehicle to vehicle. However, they are independent of location, and thus the compass can be calibrated to accommodate"
"a slip ring carrying a rotating compass rose known as the ""bearing plate"". The bearing plate has lines on it that are used to represent the wind direction during manual calculations. The top of the bearing plate was designed to be drawn on with a chinagraph pencil so it could serve as a general navigation calculator as well. On early models, rotating the compass face also rotated a shaft that ran forward under the main body of the bombsight and through a metal tube running out the lower front of the main housing. On later models, a large knob known"
"is the medical department's report of personnel at sick bay, excused from that day's duty. Before 18th century bittacle, through French ""bitacle"", from Latin ""habitaculum"", a little dwelling. Binnacle A binnacle is a waist-high case or stand on the deck of a ship, generally mounted in front of the helmsman, in which navigational instruments are placed for easy and quick reference as well as to protect the delicate instruments. Its traditional purpose was to hold the ship's magnetic compass, mounted in gimbals to keep it level while the ship pitched and rolled. A binnacle may be subdivided into sections and"
"Corf A corf (pl. corves) also spelt corve (pl. corves) is a container of wood, net, chicken wire, metal or plastic used to contain live fish, eels or crustaceans (such as crayfish) underwater, at docks or in fishing boats. 1350–1400; Middle English from Dutch and German ""Korb"", ultimately borrowed from Latin ""corbis"" basket; cf. ""corbeil"" Corves were originally crucial to keep captured fish fresh until the boat with the catch reached its harbor. A corf could be towed behind the boat while fishermen made the journey from the fishing grounds to the fish market. These journeys could last up to"
"into a gimbal mounting to reduce grounding of the needle or card when used on the pitching and rolling deck of a ship. While pivoting needles in glass boxes had already been described by the French scholar Peter Peregrinus in 1269, and by the Egyptian scholar Ibn Simʿūn in 1300, traditionally Flavio Gioja (fl. 1302), an Italian pilot from Amalfi, has been credited with perfecting the sailor's compass by suspending its needle over a compass card, thus giving the compass its familiar appearance. Such a compass with the needle attached to a rotating card is also described in a commentary"
"instrument, now held in the University Museum of Utrecht. It consisted of a brass disk on which a number of circular logarithmic scales were inscribed, with two radial wires that could each be locked to a point on the circumference. Using this instrument, a sailor could perform various trigonometric calculations by setting the wire to the position of the argument on one of the circular scales and reading the result from another of the circular scales. Ayres made fine, large Azimuth compasses, used in determining how much the magnetic compass deviated from true north. A brass mariner's compass in gimbals"
"for ships, but for diving it is generally not worth the trouble. Bearings of one diver's compass may vary from those of another diver even if they have both been read correctly. The difference should not be large, but it can result in being off course and not finding something. A compass is a magnet, and will affect another compass nearby, so they can not be checked by putting them together. The magnetic field of the earth is tilted from the horizontal. The angle is called dip and varies with place, so compasses can be corrected for different zones. This"
"used for navigation on ships, because they have two significant advantages over magnetic compasses: Aircraft commonly use gyroscopic instruments (but not a gyrocompass) for navigation and attitude monitoring; for details, see Flight instruments and Gyroscopic autopilot. A gyroscope, not to be confused with gyrocompass, is a spinning wheel mounted on a set of gimbals so that its axis is free to orient itself in any way. When it is spun up to speed with its axis pointing in some direction, due to the law of conservation of angular momentum, such a wheel will normally maintain its original orientation to a"
"Circumferentor A circumferentor, or surveyor's compass, is an instrument used in surveying to measure horizontal angles. It was superseded by the theodolite in the early 19th century. A circumferentor consists of a circular brass box containing a magnetic needle, which moves freely over a brass circle, or compass divided into 360 degrees. The needle is protected by a glass covering. A pair of sights is located on the North-South axis of the compass. Circumferentors were typically mounted on tripods and rotated on ball-and-socket joints. Circumferentors were made throughout Europe, including in England, France, Italy, and Holland. By the early 19th"