Diving Into History: Nation’s Attic’s Annual Auction Explores the Depths of Diving Innovation

On November 1, 2025, Nation’s Attic returns with its celebrated Diving Into History auction, a sale that continues to define the field of vintage and antique diving equipment. This year’s event features over 50 authentic diving helmets, along with more than 100 rare pieces of equipment and memorabilia, each offered with no reserve and accompanied by a Certificate of Authenticity from Nation’s Attic.
From early 20th-century naval helmets to experimental helium recirculators and show-stopping custom designs, the auction brings together artifacts that shaped both the history and mythology of underwater exploration. Here are five featured highlights that showcase the artistry, innovation, and daring spirit of those who ventured beneath the surface.

Auction Highlights: 

US Navy Mark V Helium “Widow Maker” Diving Helmet – USS Pigeon (Lot 63)
One of the most coveted deep-sea artifacts in existence, this U.S. Navy Mark V “Widow Maker” Helium Diving Helmet represents the daring extremes of underwater exploration. Built by DESCO in November 1970 for the U.S. Navy and deployed aboard the USS Pigeon, an advanced submarine rescue ship, this rare helium variation of the classic Mark V was designed for extreme depths. Its large rear tank contained CO₂ absorbent material, a hazardous compound that earned it the ominous nickname “Widow Maker.”


Every component remains intact, from its 12 wing nuts and glass ports to the matching serial-numbered brass hardware. Professionally polished and weighing an impressive 101 pounds of brass and copper, this fully serialized example stands as a gleaming tribute to U.S. naval innovation and the divers who risked everything beneath the surface.
Estimate: $12,500–$20,000

Rare Lindbergh-Hammar Helium Recirculator Diving Helmet – Designed by Charles Lindbergh’s Son (Lot 90)
Blending aviation heritage with underwater innovation, this remarkable Lindbergh-Hammar Helium Recirculator Helmet was co-designed by Jon Lindbergh, the son of famed aviator Charles Lindbergh, and his engineering partner Pat Hammar in the 1960s. Together, they sought to push the boundaries of deep-sea diving through mixed-gas technology.


Built upon a modified Japanese base helmet, their design introduced a unique helium recirculation system and a distinctive rear-mounted canister. Fewer than five were ever produced, making this an almost mythical collector’s piece. The example offered here retains all its specialized components, from communication fittings to the WWII-era BTE exhaust valve, and remains in excellent original condition. A historic fusion of invention and exploration, this helmet bridges the sky and the sea.
Estimate: $10,000–$20,000 

Rare Ocean Systems Mixed Gas Helium Diving Helmet (Lot 111)
A pioneering piece of subsea technology, this early Ocean Systems Inc. Helium Recirculator dates to the early 1960s and represents a critical step in the evolution of deep diving. Once part of diver and engineer Bob Ratcliffe’s personal workshop, the helmet is believed to have originated with Dan Wilson’s General Offshore Divers before the company evolved into Ocean Systems.

Its construction showcases Ratcliffe’s expert craftsmanship, complete with functioning Victor gas control valves, an Ocean Systems company plaque, and a distinctive brass light mount. The helmet’s well-preserved patina and mechanical integrity tell a story of ingenuity and hands-on experimentation that ultimately led to Ratcliffe’s later creation, the famous “Rat Hat.”
Estimate: $10,000–$20,000 

Early Bob Ratcliffe Serial #12 “Rat Hat” Diving Helmet (Lot 27)
Among the most legendary helmets in modern diving history, Bob Ratcliffe’s “Rat Hat” marked a major innovation in commercial diving design. This early example, serial #12, is one of the lowest known numbers ever handled, an extraordinary rarity for collectors.

Favored by divers for its lightweight fiberglass construction and durability, the Rat Hat was both utilitarian and iconic. This restored helmet features a rare early configuration without a carry handle and gleaming red finish, along with its original Rat Hat decal and business card. A tangible artifact from the early days of Oceaneering International, this helmet embodies the pioneering spirit of underwater engineering in the late 20th century.
Estimate: $9,000–$14,000 

Restored Catalina Island Al Hanson Historic Diving Helmet (Lot 87)
A museum-worthy artifact from California’s golden era of underwater entertainment, this scarce Al Hanson diving helmet is one of only a few personally made by the pioneering diver himself. Used by Al and Norma Hanson during their glass-bottom boat performances off Catalina Island from 1947 to 1970, its white-painted finish was designed for maximum visibility beneath the waves.

Beyond its technical beauty, with air control valves, U.S. Navy Mark V components, and oversized viewing ports for onlookers, this helmet tells a cinematic story. It appears in footage from the 1950s TV series Danger Is My Business, capturing Al Hanson’s daring underwater stunts. Accompanied by Hanson’s signed book More Than Nine Lives and related memorabilia, this piece encapsulates the artistry and showmanship that helped define American diving culture.
Estimate: $8,000–$12,000

Nation’s Attic’s Diving Into History 2025 + More auction isn’t just an event, it’s an exploration of human courage, engineering brilliance, and maritime heritage. From Navy prototypes to the handcrafted helmets of legends, each lot invites collectors and enthusiasts to own a tangible piece of diving history.

View the full catalog and register to bid on Bidsquare.com.