It is amazing what a small circle of people made all of this happen. When did Bob Ratcliffe develop the Rat Hat?
The Rat Hat dates to 1966 or 1967 when World Wide Divers in Morgan City, Louisiana called on Cal Dive—started in 1965 in Santa Barbara by Lad and Gene Handelman, Bob Ratcliffe and Kevin Lengyel—to assist with the inspection of a platform toppled by Hurricane Betsy. What World Wide lacked was the helium equipment and the deep-water experience to carry out the job. Cal Dive had both.
The platform World Wide had to inspect was lying on its side in 240 feet of water. Heavy gear, being made for going up and down, not horizontally in mid-water, was manifestly unsuited to doing a videotape inspection of a large Lego-like structure. The diver needed to be able to swim and he had to have good communications to describe what he was seeing.
Ratcliffe, Cal Dive's equipment designer, thought the Gulf Coast approach of putting a regulator and a microphone in a Desco or Scott mask was far from adequate. At Ocean Systems he had fitted the Widolf masks for the
Purisima with what he considered the best two-way mask communications, but had concluded that a lightweight helmet with completely dry speakers was a better solution. In the sledge-hammer heat, high humidity and warm water of the Gulf, a mask had the further drawback that it left the ears exposed to the water, and thus to infections. Working 12-hour shifts, day in and day out, ear infections were a common complaint.
Ratcliffe's answer was a fiberglass helmet, the Rat Hat. The Rat Hat was closely preceded but not necessarily inspired by what is generally considered the first successful lightweight helmet, the Savoie, designed by Joe Savoie of Boutte, Louisiana. Fashioned from a plastic motorcycle helmet, the Savoie fitted close to the head, had a low displacement and was easy to swim in. In the original version, the diver could open the circular faceplate, which swung up like a visor. The most important innovation was that it attached to a metal neck ring incorporating a neoprene neck seal: a feature Ratcliffe and virtually all subsequent builders of lightweight helmets adopted.
With the Rat Hat the diver breathed from a regulator mouthpiece, the first stage being mounted at the back of the helmet. Initially the helmet was worn with a wet suit. Later, when the Rat Hat became Cal Dive's standard equipment, Ratcliffe adapted it to attach to a dry suit, including the Japanese nylon heavy gear dress. Over the years it underwent numerous modifications, such as the addition of a venturi-actuated breathing system that forced gas into the lungs at slight positive pressure to overcome the difficulty of increased density at extreme depths, and two types of compact gas-heaters on the first stage, one using hot water, the other a thermal regenerator.