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58-530: OPV Nemesis is an offshore patrol vessel of the New South Wales Police Force . It was purchased in 2008 to replace two older 22-metre vessels. It is designed to support a range of police operations up to 200 nautical miles (370 km; 230 mi) out to sea, including detecting illegal immigration , smuggling and drug trafficking and supporting counter terrorism and search and rescue missions. The design specifications for

116-573: A gun data computer , a director and radar , which is designed to assist a ranged weapon system to target, track, and hit a target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more accurately. The original fire-control systems were developed for ships. The early history of naval fire control was dominated by the engagement of targets within visual range (also referred to as direct fire ). In fact, most naval engagements before 1800 were conducted at ranges of 20 to 50 yards (20 to 50 m). Even during

174-621: A yacht or rigid inflatable boat . They can include fast attack craft , torpedo boats , and missile boats . They may be broadly classified as inshore patrol vessels (IPVs) or offshore patrol vessels (OPVs). OPVs and medium size cutters are usually the smallest ship in a navy's fleet that are large and seaworthy enough to patrol off-shore in the open ocean , while IPVs are typically too small to do so and are instead kept in lakes or rivers , or close to coasts ; IPVs specifically used in rivers can also be called "riverine patrol vessels". Large patrol vessels, Heavy patrol vessels and Large cutters are

232-409: A constant rate of altitude change. The Kerrison Predictor is an example of a system that was built to solve laying in "real time", simply by pointing the director at the target and then aiming the gun at a pointer it directed. It was also deliberately designed to be small and light, in order to allow it to be easily moved along with the guns it served. The radar-based M-9/SCR-584 Anti-Aircraft System

290-409: A country's exclusive economic zone (EEZ), but they may also be used in other roles, such as anti- smuggling , anti- piracy , fishery patrols, immigration law enforcement, or search and rescue . Depending on the size, organization, and capabilities of a nation's armed forces, the importance of patrol boats may range from minor support vessels that are part of a coast guard, to flagships that make up

348-471: A critical part of an integrated fire-control system. The incorporation of radar into the fire-control system early in World War II provided ships the ability to conduct effective gunfire operations at long range in poor weather and at night. For U.S. Navy gun fire control systems, see ship gun fire-control systems . The use of director-controlled firing, together with the fire control computer, removed

406-563: A group led by Dreyer designed a similar system. Although both systems were ordered for new and existing ships of the Royal Navy, the Dreyer system eventually found most favour with the Navy in its definitive Mark IV* form. The addition of director control facilitated a full, practicable fire control system for World War I ships, and most RN capital ships were so fitted by mid 1916. The director

464-417: A majority of a navy's fleet. Their small size and relatively low cost make them one of the most common naval vessels in the world. The classification of a patrol boat is often subjective, but they are generally small naval vessels that are used to patrol national waters or a certain jurisdiction . They may be as large as a corvette or even a frigate , though the term may also be used for vessels as small as

522-484: A new computerized bombing predictor, called the Low Altitude Bombing System (LABS), began to be integrated into the systems of aircraft equipped to carry nuclear armaments. This new bomb computer was revolutionary in that the release command for the bomb was given by the computer, not the pilot; the pilot designated the target using the radar or other targeting system , then "consented" to release

580-524: A variety of armament, ranging from 12-inch coast defense mortars, through 3-inch and 6-inch mid-range artillery, to the larger guns, which included 10-inch and 12-inch barbette and disappearing carriage guns, 14-inch railroad artillery, and 16-inch cannon installed just prior to and up through World War II. Fire control in the Coast Artillery became more and more sophisticated in terms of correcting firing data for such factors as weather conditions,

638-853: Is also used to assist the Australian Fisheries Management Authority and the Australian Border Force . Officers on board carry firearms and the vessel itself is able to be fitted with mounted weapons. Nemesis was part of the support patrol for the 2009 Sydney to Hobart Yacht Race . In 2010, the NSW Police was criticised for only operating the ship for 403 hours in 2009. Deployments were subsequently increased to 80 hours per month. [REDACTED] Media related to Nemesis (ship, 2008) at Wikimedia Commons Offshore patrol vessel Per their name, patrol boats are primarily used to patrol

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696-401: Is being tracked. Typically, weapons fired over long ranges need environmental information—the farther a munition travels, the more the wind, temperature, air density, etc. will affect its trajectory, so having accurate information is essential for a good solution. Sometimes, for very long-range rockets, environmental data has to be obtained at high altitudes or in between the launching point and

754-633: The Pegasus class of armed hydrofoils for years in a patrol boat role. During the Vietnam War , the U.S. Navy ordered 193 aluminum hulled Patrol Craft, Fast (PCFs), also known as Swiftboats , for brown water naval operations. The Patrol Boat, River (PBR, sometimes called "Riverine" and "Pibber") was a fiberglass hulled vessel also designed and used for inland river operations during the Vietnam War, and became an icon of water operations during

812-486: The American Civil War , the famous engagement between USS  Monitor and CSS  Virginia was often conducted at less than 100 yards (90 m) range. Rapid technical improvements in the late 19th century greatly increased the range at which gunfire was possible. Rifled guns of much larger size firing explosive shells of lighter relative weight (compared to all-metal balls) so greatly increased

870-623: The grenade launcher developed for use on the Fabrique Nationale F2000 bullpup assault rifle. Fire-control computers have gone through all the stages of technology that computers have, with some designs based upon analogue technology and later vacuum tubes which were later replaced with transistors . Fire-control systems are often interfaced with sensors (such as sonar , radar , infra-red search and track , laser range-finders , anemometers , wind vanes , thermometers , barometers , etc.) in order to cut down or eliminate

928-423: The heads-up display (HUD). The pipper shows the pilot where the target must be relative to the aircraft in order to hit it. Once the pilot maneuvers the aircraft so that the target and pipper are superimposed, he or she fires the weapon, or on some aircraft the weapon will fire automatically at this point, in order to overcome the delay of the pilot. In the case of a missile launch, the fire-control computer may give

986-400: The Dreyer table) for HMS Hood ' s main guns housed 27 crew. Directors were largely unprotected from enemy fire. It was difficult to put much weight of armour so high up on the ship, and even if the armour did stop a shot, the impact alone would likely knock the instruments out of alignment. Sufficient armour to protect from smaller shells and fragments from hits to other parts of the ship

1044-561: The air, and other adjustments. Around 1905, mechanical fire control aids began to become available, such as the Dreyer Table , Dumaresq (which was also part of the Dreyer Table), and Argo Clock , but these devices took a number of years to become widely deployed. These devices were early forms of rangekeepers . Arthur Pollen and Frederic Charles Dreyer independently developed the first such systems. Pollen began working on

1102-418: The amount of information that must be manually entered in order to calculate an effective solution. Sonar, radar, IRST and range-finders can give the system the direction to and/or distance of the target. Alternatively, an optical sight can be provided that an operator can simply point at the target, which is easier than having someone input the range using other methods and gives the target less warning that it

1160-548: The analog rangekeepers, at least for the US Navy, was in the 1991 Persian Gulf War when the rangekeepers on the Iowa -class battleships directed their last rounds in combat. An early use of fire-control systems was in bomber aircraft , with the use of computing bombsights that accepted altitude and airspeed information to predict and display the impact point of a bomb released at that time. The best known United States device

1218-680: The astonishing feat of shooting down V-1 cruise missiles with less than 100 shells per plane (thousands were typical in earlier AA systems). This system was instrumental in the defense of London and Antwerp against the V-1. Although listed in Land based fire control section anti-aircraft fire control systems can also be found on naval and aircraft systems. In the United States Army Coast Artillery Corps , Coast Artillery fire control systems began to be developed at

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1276-668: The barrels and distortion due to heating. These sorts of effects are noticeable for any sort of gun, and fire-control computers have started appearing on smaller and smaller platforms. Tanks were one early use that automated gun laying had, using a laser rangefinder and a barrel-distortion meter. Fire-control computers are useful not just for aiming large cannons , but also for aiming machine guns , small cannons, guided missiles , rifles , grenades , and rockets —any kind of weapon that can have its launch or firing parameters varied. They are typically installed on ships , submarines , aircraft , tanks and even on some small arms —for example,

1334-570: The bearings and elevations for the guns to fire upon. In the turrets, the gunlayers adjusted the elevation of their guns to match an indicator for the elevation transmitted from the Fire Control table—a turret layer did the same for bearing. When the guns were on target they were centrally fired. Even with as much mechanization of the process, it still required a large human element; the Transmitting Station (the room that housed

1392-668: The condition of powder used, or the Earth's rotation. Provisions were also made for adjusting firing data for the observed fall of shells. As shown in Figure 2, all of these data were fed back to the plotting rooms on a finely tuned schedule controlled by a system of time interval bells that rang throughout each harbor defense system. It was only later in World War II that electro-mechanical gun data computers , connected to coast defense radars, began to replace optical observation and manual plotting methods in controlling coast artillery. Even then,

1450-622: The control of the gun laying from the individual turrets to a central position; although individual gun mounts and multi-gun turrets would retain a local control option for use when battle damage limited director information transfer (these would be simpler versions called "turret tables" in the Royal Navy). Guns could then be fired in planned salvos, with each gun giving a slightly different trajectory. Dispersion of shot caused by differences in individual guns, individual projectiles, powder ignition sequences, and transient distortion of ship structure

1508-403: The direction and elevation of the guns. Pollen aimed to produce a combined mechanical computer and automatic plot of ranges and rates for use in centralised fire control. To obtain accurate data of the target's position and relative motion, Pollen developed a plotting unit (or plotter) to capture this data. To this he added a gyroscope to allow for the yaw of the firing ship. Like the plotter,

1566-505: The end of the 19th century and progressed on through World War II. Early systems made use of multiple observation or base end stations (see Figure 1 ) to find and track targets attacking American harbors. Data from these stations were then passed to plotting rooms , where analog mechanical devices, such as the plotting board , were used to estimate targets' positions and derive firing data for batteries of coastal guns assigned to interdict them. U.S. Coast Artillery forts bristled with

1624-484: The fall of shot. Visual range measurement (of both target and shell splashes) was difficult prior to the availability of radar. The British favoured coincidence rangefinders while the Germans favoured the stereoscopic type . The former were less able to range on an indistinct target but easier on the operator over a long period of use, the latter the reverse. Submarines were also equipped with fire control computers for

1682-409: The fire control computer became integrated with ordnance systems, the computer can take the flight characteristics of the weapon to be launched into account. By the start of World War II , aircraft altitude performance had increased so much that anti-aircraft guns had similar predictive problems, and were increasingly equipped with fire-control computers. The main difference between these systems and

1740-425: The firing solution based upon the observation of preceding shots. The resulting directions, known as a firing solution , would then be fed back out to the turrets for laying. If the rounds missed, an observer could work out how far they missed by and in which direction, and this information could be fed back into the computer along with any changes in the rest of the information and another shot attempted. At first,

1798-508: The guns were aimed using the technique of artillery spotting . It involved firing a gun at the target, observing the projectile's point of impact (fall of shot), and correcting the aim based on where the shell was observed to land, which became more and more difficult as the range of the gun increased. Between the American Civil War and 1905, numerous small improvements, such as telescopic sights and optical rangefinders , were made in fire control. There were also procedural improvements, like

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1856-460: The individual gun crews. Director control aims all guns on the ship at a single target. Coordinated gunfire from a formation of ships at a single target was a focus of battleship fleet operations. Corrections are made for surface wind velocity, firing ship roll and pitch, powder magazine temperature, drift of rifled projectiles, individual gun bore diameter adjusted for shot-to-shot enlargement, and rate of change of range with additional modifications to

1914-492: The individual gun turrets to the director tower (where the sighting instruments were located) and the analogue computer in the heart of the ship. In the director tower, operators trained their telescopes on the target; one telescope measured elevation and the other bearing. Rangefinder telescopes on a separate mounting measured the distance to the target. These measurements were converted by the Fire Control Table into

1972-913: The largest type of patrol ships and are typically more than 100 m (330 ft) in length. Seagoing patrol boats are typically around 30 m (100 ft) in length and usually carry a single medium caliber artillery gun as main armament, and a variety of lighter secondary armament such as machine guns , while others include the sophisticated close-in weapon system . Depending on their role, vessels in this class may also have more sophisticated sensors and fire control systems that would enable them to carry torpedoes , anti-ship missiles , and surface-to-air missiles . During both World Wars, in order to rapidly build up numbers, all sides created auxiliary patrol boats by arming motorboats and seagoing fishing trawlers with machine guns and obsolete naval weapons. Some modern patrol vessels are still based on fishing and leisure boats. The United States Navy operated

2030-464: The manual methods were retained as a back-up through the end of the war. Land based fire control systems can be used to aid in both Direct fire and Indirect fire weapon engagement. These systems can be found on weapons ranging from small handguns to large artillery weapons. Modern fire-control computers, like all high-performance computers, are digital. The added performance allows basically any input to be added, from air density and wind, to wear on

2088-549: The ones on ships was size and speed. The early versions of the High Angle Control System , or HACS, of Britain 's Royal Navy were examples of a system that predicted based upon the assumption that target speed, direction, and altitude would remain constant during the prediction cycle, which consisted of the time to fuze the shell and the time of flight of the shell to the target. The USN Mk 37 system made similar assumptions except that it could predict assuming

2146-468: The period 2010–2014 List of Irish Naval Service vessels; Additionally, the Royal Swedish Navy also operates smaller types of patrol boats (Swedish: bevakningsbåt = "guard boat"): The Swedish Coast Guard operate an additional 22 patrol vessels for maritime surveillance. Fire-control system A fire-control system ( FCS ) is a number of components working together, usually

2204-471: The plane maintain a constant attitude (usually level), though dive-bombing sights were also common. The LABS system was originally designed to facilitate a tactic called toss bombing , to allow the aircraft to remain out of range of a weapon's blast radius . The principle of calculating the release point, however, was eventually integrated into the fire control computers of later bombers and strike aircraft, allowing level, dive and toss bombing. In addition, as

2262-543: The primitive gyroscope of the time required substantial development to provide continuous and reliable guidance. Although the trials in 1905 and 1906 were unsuccessful, they showed promise. Pollen was encouraged in his efforts by the rapidly rising figure of Admiral Jackie Fisher , Admiral Arthur Knyvet Wilson and the Director of Naval Ordnance and Torpedoes (DNO), John Jellicoe . Pollen continued his work, with occasional tests carried out on Royal Navy warships. Meanwhile,

2320-402: The problem after noting the poor accuracy of naval artillery at a gunnery practice near Malta in 1900. Lord Kelvin , widely regarded as Britain's leading scientist first proposed using an analogue computer to solve the equations which arise from the relative motion of the ships engaged in the battle and the time delay in the flight of the shell to calculate the required trajectory and therefore

2378-414: The range of the guns that the main problem became aiming them while the ship was moving on the waves. This problem was solved with the introduction of the gyroscope , which corrected this motion and provided sub-degree accuracies. Guns were now free to grow to any size, and quickly surpassed 10 inches (250 mm) calibre by the 1890s. These guns were capable of such great range that the primary limitation

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2436-696: The rangekeeper. The effectiveness of this combination was demonstrated in November 1942 at the Third Battle of Savo Island when the USS ; Washington engaged the Japanese battleship Kirishima at a range of 8,400 yards (7.7 km) at night. Kirishima was set aflame, suffered a number of explosions, and was scuttled by her crew. She had been hit by at least nine 16-inch (410 mm) rounds out of 75 fired (12% hit rate). The wreck of Kirishima

2494-414: The same reasons, but their problem was even more pronounced; in a typical "shot", the torpedo would take one to two minutes to reach its target. Calculating the proper "lead" given the relative motion of the two vessels was very difficult, and torpedo data computers were added to dramatically improve the speed of these calculations. In a typical World War II British ship the fire control system connected

2552-654: The ship were drawn in 2005, taking into account lessons from the Pong Su incident . Nemesis was built by Tenix Defence in Henderson, Western Australia based on the 35-metre (115 ft) Ilocos Norte -class ships built by Tenix for the Philippine Coast Guard . At the time of its construction, Nemesis was the largest purpose-built police boat in the Southern Hemisphere . The vessel

2610-401: The target or flying the aircraft. Even if the system is unable to aim the weapon itself, for example the fixed cannon on an aircraft, it is able to give the operator cues on how to aim. Typically, the cannon points straight ahead and the pilot must maneuver the aircraft so that it oriented correctly before firing. In most aircraft the aiming cue takes the form of a " pipper " which is projected on

2668-429: The target ship could move a considerable distance, several ship lengths, between the time the shells were fired and landed. One could no longer eyeball the aim with any hope of accuracy. Moreover, in naval engagements it is also necessary to control the firing of several guns at once. Naval gun fire control potentially involves three levels of complexity. Local control originated with primitive gun installations aimed by

2726-410: The target. Often, satellites or balloons are used to gather this information. Once the firing solution is calculated, many modern fire-control systems are also able to aim and fire the weapon(s). Once again, this is in the interest of speed and accuracy, and in the case of a vehicle like an aircraft or tank, in order to allow the pilot/gunner/etc. to perform other actions simultaneously, such as tracking

2784-482: The use of plotting boards to manually predict the position of a ship during an engagement. Then increasingly sophisticated mechanical calculators were employed for proper gun laying , typically with various spotters and distance measures being sent to a central plotting station deep within the ship. There the fire direction teams fed in the location, speed and direction of the ship and its target, as well as various adjustments for Coriolis effect , weather effects on

2842-831: The war due to its use in the 1979 film Apocalypse Now . Most modern designs are powered by gas turbine arrangements such as CODAG , and speeds are generally in the 25–30 knots (46–56 km/h; 29–35 mph) range. The largest OPVs might also have a flight deck and helicopter embarked. In times of crisis or war, these vessels are expected to support the larger vessels in a navy, though some smaller navies are mostly composed of just patrol boats. 35m Fast Patrol Vessels- USA -built by Swiftships, Commissioned in 2021 The Bangladesh Navy classified its medium size patrol ships as large patrol craft (LPC) which are armed with either anti-ship missiles or torpedoes . Those ships typically have heavier armaments but less range than OPVs. 35m Fast Patrol Vessels- USA -built by Swiftships, during

2900-444: The weapon, and the computer then did so at a calculated "release point" some seconds later. This is very different from previous systems, which, though they had also become computerized, still calculated an "impact point" showing where the bomb would fall if the bomb were released at that moment. The key advantage is that the weapon can be released accurately even when the plane is maneuvering. Most bombsights until this time required that

2958-435: Was discovered in 1992 and showed that the entire bow section of the ship was missing. The Japanese during World War II did not develop radar or automated fire control to the level of the US Navy and were at a significant disadvantage. By the 1950s gun turrets were increasingly unmanned, with gun laying controlled remotely from the ship's control centre using inputs from radar and other sources. The last combat action for

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3016-555: Was high up over the ship where operators had a superior view over any gunlayer in the turrets . It was also able to co-ordinate the fire of the turrets so that their combined fire worked together. This improved aiming and larger optical rangefinders improved the estimate of the enemy's position at the time of firing. The system was eventually replaced by the improved " Admiralty Fire Control Table " for ships built after 1927. During their long service life, rangekeepers were updated often as technology advanced, and by World War II they were

3074-405: Was seeing the target, leading to the use of high masts on ships. Another technical improvement was the introduction of the steam turbine which greatly increased the performance of the ships. Earlier reciprocating engine powered capital ships were capable of perhaps 16 knots, but the first large turbine ships were capable of over 20 knots. Combined with the long range of the guns, this meant that

3132-454: Was the Norden bombsight . Simple systems, known as lead computing sights also made their appearance inside aircraft late in the war as gyro gunsights . These devices used a gyroscope to measure turn rates, and moved the gunsight's aim-point to take this into account, with the aim point presented through a reflector sight . The only manual "input" to the sight was the target distance, which

3190-410: Was the limit. The performance of the analog computer was impressive. The battleship USS  North Carolina during a 1945 test was able to maintain an accurate firing solution on a target during a series of high-speed turns. It is a major advantage for a warship to be able to maneuver while engaging a target. Night naval engagements at long range became feasible when radar data could be input to

3248-463: Was typically handled by dialing in the size of the target's wing span at some known range. Small radar units were added in the post-war period to automate even this input, but it was some time before they were fast enough to make the pilots completely happy with them. The first implementation of a centralized fire control system in a production aircraft was on the B-29 . By the start of the Vietnam War,

3306-562: Was undesirably large at typical naval engagement ranges. Directors high on the superstructure had a better view of the enemy than a turret mounted sight, and the crew operating them were distant from the sound and shock of the guns. Gun directors were topmost, and the ends of their optical rangefinders protruded from their sides, giving them a distinctive appearance. Unmeasured and uncontrollable ballistic factors, like high-altitude temperature, humidity, barometric pressure, wind direction and velocity, required final adjustment through observation of

3364-521: Was used to direct air defense artillery since 1943. The MIT Radiation Lab's SCR-584 was the first radar system with automatic following, Bell Laboratory 's M-9 was an electronic analog fire-control computer that replaced complicated and difficult-to-manufacture mechanical computers (such as the Sperry M-7 or British Kerrison predictor). In combination with the VT proximity fuze , this system accomplished

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