Ship Fire Control Sets

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Mark 3 Medium Wave Fire Control for Main Batteries

Mark 3 With 3'x12' Antenna on Mark 38 Director - indicating antenna, track indicator, range unit and control indicator.
Mark 3 With 3'x12' Antenna on Mark 38 Director

DESCRIPTION: Medium wave fire control for main batteries. Type "A" range indication and pip-matching for train. Has provisions for IFF connections, for identification of targets. Search radar designates target area.
USES: Furnishes bearing and range to the mark 34 and Mark 38 directors for guns 6" or larger. It is not readily suitable for spotting the fall of the shot, except in range.
PERFORMANCE: Reliable maximum range is 16,000 yds. for destroyer targets, 28,000 for battleships; minimum range is 1,000 yds.; range accuracy ± 40 yds. Azimuth accuracy is ± 4 mils for 6'x6' antenna or ± 2 mils for 3'x12' antenna.
TRANSPORTABILITY: Radar is packed in 7 or 8 cases, weighing 3700 lbs., plus crated antenna mount.
INSTALLATION: Of the seven components, the control-indicator, range units and train indicator are installed in the director. Equipment has either 3'x12' or 6'x6' antenna.
PERSONNEL: One range operator and one maintenance man per set, in addition to regular director personnel, are required.
POWER: Primary power required is 2.2 KW, 115 V, 60-cycle single phase, derived from ship's generators.

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Mark 8 Microwave Fire Control for Main Batteries

Mark 8 in Mark 34 Director - indicating on target side Mark 8 antenna: scanning switch panel, scan position indicators, train indicator, junction box, regulated rectifiers, high voltage rectifier, transformer assembly, juntion boxes, and antenna; Rear view Mark 8 antenna: scanning motor panel, transmitter, power control unit, range unit, control indicator, and wave guide.
Mark 8 in Mark 34 Director

DESCRIPTION: Microwave fire control for main batteries. "A" and B indication. Search radar provides target designation. Equipment has provisions for IFF connections, for identification of targets.
USES: Mark 8 is used with the gun directors Mark 34 and 38. It provides both bearing and range. It permits spotting in range and deflection -- it being possible to detect shell splashes. The equipment is for use with guns 6" and larger.
PERFORMANCE: Reliable maximum range (on cruisers with antenna 120 ft. above water): 40,000 yards. Reliable minimum range: 500 yards. Range accuracy: ± (15 yards + 0.1% of range.) Bearing accuracy: 0.1° to 2 mils. Elevation limits: +55° to -20° for level; no cross-level.
TRANSPORTABILITY: Shipment includes spares for a year and testing equipment. Complete shipment is packed in 47 boxes, weighing (spares included) a total of 14,485 lbs.
INSTALLATION: The 13 components of Mark 8 are installed in or near the director, as shown in the above drawing.
PERSONNEL: Minimum personnel is 1 operator and 1 maintenance man, plus director crew.
POWER: Primary power required: 4 KW, 440 V, 3 phase, 60 cycles. Source of power is ship's supply.

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Mk 4 and *Mk 12 Medium wave Fire Control for dual Purpose batteries

Mark 4 in Mark 37 Director - indicating elevator indicator, train indicator, range transmitter, selector switch, and control unit,.
Mark 4 in Mark 37 Director

DESCRIPTION: Medium wave fire control for dual purpose batteries. "A" type range indicator and two pip-matching train and elevation indicators. Search radar provides target designation. Equipment has provisions for IFF connections for identification of targets.
USES: Mark 4 is used on the all-purpose directors Mk. 33 and Mk. 37 with 5-inch guns. It furnishes elevation, bearing, and range, though at elevation angles below 10° the elevation angle is likely to be in error. Set is useful in getting a solution into the computer before the target gets into the range of visibility. Mark 12 will be a higher-powered set which will replace the Mark 4 in the Mark 37 director (square-backed type).
PERFORMANCE: Reliable maximum ranges for mark 4: 35,000 yds. on PBY at 5,000', 16,000 yds. on destroyers, 25,000 yds. on battleships. Minimum range, 1,000 yds. Range accuracy, ± 40 yds. Bearing limits, 720° for director train. Bearing accuracy ± 4 mils. Elevation limits, +110° to -20°. Elevation accuracy, (above 10°) ± 4 mils. For Mark 12, maximum reliable range on PBY is 40,000 yds. Range accuracy will be ± 25 yds., accuracy in elevation (above 7°) and reading will be ± 2 mils.
TRANSPORTABILITY: Radar is packed in 7 or 8 cases weighing 3800 lbs., plus crated antenna mount. Testing equipment and spares for one year are included.
INSTALLATION: Mark 4 will have the control-indicator, range unit, and two train and/or elevation indicators mounted in the director. Mark 12 installation will be similar, but there will be four train and/or elevation indicators in the director.
PERSONNEL: One radar range operator and one maintenance man are required in addition the director crew.
POWER: Primary power required is 2.4 KW, 115 V, 60-cycle single phase, supplied by ship's generators.

* Available for issue in latter part of 1943.

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*Mark 10 Microwave Antiaircraft Fire Control

Mark 10 in Mark 50 Director indicating transmitter, antenna, terminal assembly, train and elevation, and modulator and indicator assembly.
Mark 10 in Mark 50 Director

DESCRIPTION: Microwave AA fire control for Mark 50 directors.
USES: The Mark 50 is used with 40 mm guns, and may be used with 3" or 5" AA guns when proper ballistics are available. The Mark 10 radar gives both direction and range of target, range by means of "A" indication, direction by a moving spot indicator. Search radar provides target designation. Equipment has no provisions for IFF identification connections.
PERFORMANCE: Reliable maximum range: Mark 10, Mods. 0 and 1 -- 10,000 yds; Mods. 2 and 3 -- 15,000 yds. Minimum range; 300 yds. Range accuracy ± (15 yds. + 0.1% of range.) Bearing accuracy ± 0.25°. Elevation limits: 100° elevation, 25° depression. Elevation accuracy: ± 0.25°.
TRANSPORTABILITY: Set, including spares for one year, is packed in 17 boxes. The largest is 75" x 36" x 36" and weighs 1200 lbs. Total weight of shipment when crated is 2760 lbs.
INSTALLATION: Mark 10 consists of approximately 7 components. Most of these, including the transmitter, modulator, and all indicators, will be installed in the director. Their total weight will be about 1200 lbs.
PERSONNEL: Minimum operating personnel: 1 radar range operator and one director operator who points by either radar or optics; minimum maintenance, one.
POWER: Primary power required is 1.7 KW, 115 V, 60 cycles, single phase. Source of power is ship's line.

* Available for issue in latter part of 1943.

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*Mark 11 and *Mark 19 Microwave Antiaircraft Fire Control

Mark 11 in Mark 49 Director and Gun Mount indication transmitter, antenna, computer, modulator, and power supply blower.
Mark 11 in Mark 49 Director and Gun Mount

DESCRIPTION: Microwave AA fire control for automatic weapons.
USES: Mark 11 furnishes range only on circular "A" scope; Mark 19 provides range on "A" scope, and bearing and elevation on moving spot indicator. Search radar designates target area. No provisions for IFF identification of targets.
PERFORMANCE: For Mark 11, reliable maximum range on medium planes is 6,000 yards, reliable minimum range is 600 yards; range accuracy is ± 70 yds. Director train is unlimited. Elevation limits are from -30° to ± 115°. Mark 19 has a reliable maximum range of 12,000 yds. on medium bombers; a minimum range of 400 yds., and a range accuracy of ± (15 yds. + 0.1% of range). Bearing accuracy is ± 4 mils. Elevation accuracy (above 10°) is ± 4 mils.
TRANSPORTABILITY: Shipment includes spares for a year, and will be air transportable.
INSTALLATION: For the Mark 11, all components except receiver and control-indicator are mounted on or within the director. For the Mark 19, all control units will be mounted below deck.
PERSONNEL: Minimum operating personnel required: 1 radar range operator, 1 director operator who points by optics or radar. For normal operations all day, 5 men are recommended.
POWER: Primary power required for Mark 11 is 750 watts, 115 V, 60 cycles, single phase; for Mark 19, 1.4 KW, from ship's supply.

* Available for issue in latter part of 1943.

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