No bolt (lock) helmet


A Siebe Gorman lock helmet with a close up of the breastplate badge.
The No bolt helmet is also referred to as the ''Lock'' helmet. Like the 3 bolt version, this dress has a small opening and it could take 3 tenders to keep the collar open whilst the diver gets inside the suit. The dress is clamped between the bonnet and there breastplate. The lower rim of the corselet rests freely on the outside of the dress. The helmet is hinged at the back to the breastplate and clamped at the front with a locking device which creates a watertight seal. This device was also used by a French helmet maker, Rene Piel as seen in the adjacent picture. For pictures of a French no bolt helmet please visit the French section

The Siebe Gorman helmet has 4 lights and could be fitted with the metal cross bars if required. The catalogue code name was 'Conen' and the matching suit was catalo code name 'Erfar' The price for the helmet and suit when bought new in the 1930 s was around 50 .00

Siebe Gorman No bolt helmet or 'Lock' Helmet


Photos courtesy of David Dekker

Front and back view or a Siebe Gorman Lock helmet with some different features to the one above.
The connection on the crown of the helmet is for the acoustic telephone device.

Photo by Diving Heritage