Nautical compass - Copper - Compass with alidade
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Copper Admiralty Pattern compass from 1930–1940 with an optical alidade, UK origin, weight 2.5 kg, 15.5 cm diameter and 8 cm height, in good vintage condition with original patina and provenance to the Ortac yacht (1937).
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Description from the seller
Royal Navy Pat. 01151A Copper Nautical Compass with Optical Azimuth Ring Pat. 1152 – belonging to the yacht "Ortac" (1937)
Description:
Exceptional high-precision nautical instrument set with historical value. A unique lot is offered at auction, consisting of a British Admiralty standard compass and its original matching optical alidade. Designed under the demanding patents and technical norms of the Royal Navy, this specific instrument also has legendary civil provenance: it was originally installed in the cockpit of the mythical regatta yacht Ortac (1937), a 15-meter jewel designed by Robert Clark, built at Morgan Giles shipyard and famous for being the first yacht in the world with an iron bow pulpits.
Included components and historical details:
1. Admiralty Pattern 01151A Liquid Compass: Manufactured by the British Admiralty’s official precision instrument contractors (historic firms associated with Kelvin & Hughes or Henry Browne & Son / Sestrel). Unlike conventional brass, its exterior structure is solidly cast in genuine copper with a dark anti-reflective and marine protective patina treatment. This mandatory military specification prevented sun glare from dazzling the helmsman or betraying the ship’s position on combat missions. It features an internal gimbal suspension system and a dial graduated in quadrants protected by a shatterproof crystal. The bezel bears the official military pattern code and its unique serial number: "PATT. 01151A.COMPASS Nº 7443.H".
2. Azimuthal Circle / Optical Alidade Pattern 1152: The detachable optical accessory vital for high navigation, designed with a military patent to couple with millimetre precision onto this copper bezel. Its function is to calculate delays and azimuths of celestial bodies or coastlines. It includes a high-precision reflector prism with a V-shaped sight that allows the observer to point to the horizon and simultaneously see the exact degree reading reflected on the lower dial of the compass. It features fold-down dark sun filters and a regulation mechanism operated by a knurled bronze knob to take direct solar measurements without glare. The official pattern "PATT. 1152" is engraved.
Technical details and dimensions:
• Patent and History: Official Admiralty instrument (WWII era).
• Civil Historical Provenance: Transoceanic regatta yacht Ortac (1937), designed by Robert Clark / built by Morgan Giles.
• Materials: Die-cast copper with anti-reflection patina, bronze components, precision prism optics and heavy nautical crystal.
• Compass diameter: 15.5 cm; height: 8 cm.
• Mounted accessory dimensions: total diameter 16 cm.
• Compass weight: 2.5 kg
• Azimuth circle weight: 300 g
• Condition: Good vintage collectible condition. Retains its original dark technical patina on copper. Clear optics, legible dials, and all movable and fastenings in good working order. (See photographs for detailed visual assessment).
Royal Navy Pat. 01151A Copper Nautical Compass with Optical Azimuth Ring Pat. 1152 – belonging to the yacht "Ortac" (1937)
Description:
Exceptional high-precision nautical instrument set with historical value. A unique lot is offered at auction, consisting of a British Admiralty standard compass and its original matching optical alidade. Designed under the demanding patents and technical norms of the Royal Navy, this specific instrument also has legendary civil provenance: it was originally installed in the cockpit of the mythical regatta yacht Ortac (1937), a 15-meter jewel designed by Robert Clark, built at Morgan Giles shipyard and famous for being the first yacht in the world with an iron bow pulpits.
Included components and historical details:
1. Admiralty Pattern 01151A Liquid Compass: Manufactured by the British Admiralty’s official precision instrument contractors (historic firms associated with Kelvin & Hughes or Henry Browne & Son / Sestrel). Unlike conventional brass, its exterior structure is solidly cast in genuine copper with a dark anti-reflective and marine protective patina treatment. This mandatory military specification prevented sun glare from dazzling the helmsman or betraying the ship’s position on combat missions. It features an internal gimbal suspension system and a dial graduated in quadrants protected by a shatterproof crystal. The bezel bears the official military pattern code and its unique serial number: "PATT. 01151A.COMPASS Nº 7443.H".
2. Azimuthal Circle / Optical Alidade Pattern 1152: The detachable optical accessory vital for high navigation, designed with a military patent to couple with millimetre precision onto this copper bezel. Its function is to calculate delays and azimuths of celestial bodies or coastlines. It includes a high-precision reflector prism with a V-shaped sight that allows the observer to point to the horizon and simultaneously see the exact degree reading reflected on the lower dial of the compass. It features fold-down dark sun filters and a regulation mechanism operated by a knurled bronze knob to take direct solar measurements without glare. The official pattern "PATT. 1152" is engraved.
Technical details and dimensions:
• Patent and History: Official Admiralty instrument (WWII era).
• Civil Historical Provenance: Transoceanic regatta yacht Ortac (1937), designed by Robert Clark / built by Morgan Giles.
• Materials: Die-cast copper with anti-reflection patina, bronze components, precision prism optics and heavy nautical crystal.
• Compass diameter: 15.5 cm; height: 8 cm.
• Mounted accessory dimensions: total diameter 16 cm.
• Compass weight: 2.5 kg
• Azimuth circle weight: 300 g
• Condition: Good vintage collectible condition. Retains its original dark technical patina on copper. Clear optics, legible dials, and all movable and fastenings in good working order. (See photographs for detailed visual assessment).
Details
Era
1900-2000
Title additional information
Compass with alidade
Number of objects
1
Country of origin
United Kingdom
Material
Copper
Style
Industrial
Condition
Good condition - used with small signs of aging & blemishes
Height
8 cm
Width
15.5 cm
Depth
15.5 cm
Military Context
No
Weight
2.5 kg
Estimated period
1930-1940
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