3 Bolt Diving Helmet Appraisal

Antique Deep-Sea Diving Helmet

This is an antique deep-sea diving helmet, likely a replica or display piece given its condition and lack of significant wear/tear for an original working helmet. It features a robust construction primarily of polished copper for the main body of the helmet and corselet, beautifully contrasting with brass components including the circular front viewport, side port windows, top air intake, and securing mechanisms. The front viewport is protected by a brass grid, indicating potential use or reproduction of a helmet designed for hazardous underwater conditions. Various brass fixtures, such as what appear to be air inlet/outlet valves and securing nuts, are visible around the helmet and corselet. The corselet, the lower part that rests on the diver's shoulders, has a brass rim with visible turn-to-tighten knobs and is mounted on a wooden base, possibly original to the piece or added for display. A prominent brass plate, likely a manufacturer's plaque or informative label, is affixed to the front of the corselet, though its specific inscription ('CROSBY CO' is partially legible) remains unclear without a clearer image, which could significantly impact its provenance and value. The copper shows a rich, warm patina with some areas of darker oxidation and minor surface blemishes, consistent with age and exposure, but generally well-maintained. The brass elements exhibit a bright, slightly tarnished finish typical of aged brass. Visually, the helmet appears to be in very good condition, suggesting it has been preserved as a decorative item rather than experiencing the rigors of actual deep-sea use. The craftsmanship appears high, with carefully riveted and soldered seams, indicating a quality construction. The style points to an era of traditional deep-sea diving equipment, likely late 19th to early 20th century in design, possibly representing a U.S. Navy or commercial diving helmet of that period.