1920'S Siebe Gorman & Co Ltd Twelve Bolt Diving Helmet & Corselet with Matching Serial Numbers

A mid-1920’s Siebe Gorman & Co Ltd twelve bolt diving helmet and corselet with matching serial numbers throughout.

The helmet is of copper construction with an oval port to each side covered with brass grills and circular front port with threaded front plate to allow for communication with the diver when out of the water.

This port is stamped with the serial number 10375. To the left of the front port it has a spit cock valve named for it use in sucking in a small amount of water into the diver’s mouth and spitting it onto a steamed up port

To the reverse, the helmet has an air inlet with non-return valve, exhaust valve and communications elbow with end cap stamped with “telephone” to the face. The communications speaker and comms button remain present inside the helmet and it is also stamped inside with the serial number 10375

The corselet or breast plate (also stamped with serial number 10375 to the neck ring) is primarily used for distributing the weight of the helmet onto the diver’s shoulders and as a means of attaching and sealing the suit to the helmet. The helmet derives its name from the twelve bolts that surround the base of the corselet. These bolts hold the brails in place that ultimately clamp the diving suit in place and create a seal. All four brails are also stamped with the serial number 10375.

To the front of the corselet, the front brail is stamped to Siebe Gorman & Co Ltd and above it retains its brass Siebe Gorman & Co Ltd plaque. It reads, “Siebe Gorman & Co Ltd, Submarine Engineers, London. Patent.”.

The company of Siebe Gorman has a long and illustrious history, founded originally as A. Siebe after Augustus Siebe, a Prussian artillery officer who was present at both the Battle of Leipzig and also the Battle of Waterloo. A year after Waterloo, Siebe moved to London to become a mechanical engineer and invented a rotating water pump that marked the start of his fortune. Commissioned in the early 1830’s to redesign the Deane Brothers smoke helmet into a diving helmet, after numerous developments in 1839, the first full dress diving suit and helmet was created and was being actively used by the Royal Navy in salvage operations by 1840.

Siebe continued to design and develop diving equipment until his retirement in 1868 after which point the company of Siebe & Gorman was formed. The partnership was comprised of his son Henry Siebe and his son in law the Sea Captain William Gorman, it remained trading from the address of 5 Denmark Street, London.

Siebe died in 1887 but Gorman maintained control of the company until his death in 1904 whereafter it was sold to the Vickers family most famous for creating the Vicker’s machine gun and turned into a limited company in 1905. It became a public company in 1952 and moved its operations out of London to Wales in 1975. In 1999 it merged with a company named BTR and renamed itself as Invensys and was finally merged with a French parent company called Schneider in 2014.