Post by NOAA: National Oceanic & Atmospheric Administration

This diving helmet from around 1940 didn't seal while in use. Instead it used a hose to pump in air, creating a pocket inside the helmet.The diver had to be extremely careful to stay upright so that the helmet wouldn't flood with water. In the oldest known diving photo from NOAA's past, circa 1940, a U.S. Coast & Geodetic Survey (a predecessor of NOAA) diver suits up to cut a cable fouling the propeller of the Survey Ship Lydonia. A skiff alongside the coastal survey ship Lydonia is used as the dive platform. A chief petty officer (left) and crewman in the boat lowered the helmet over the diver's head. These shallow water diving helmets were held onto the diver's shoulders by their weight (note the rectangular lead weights on the helmet's collar) and were used without the special gear and diving suits required with deep sea diving rigs. A compressor on the ship's deck fed air to the diver via a hose affixed to the right side of the helmet. A Jacob's ladder is rigged to the boat at the diver's left to assist him in getting in and out of the skiff. This simple diving equipment was well-suited to the kind of work being done in the photo — unfouling props and rudders, inspecting hulls for damage, and similar tasks — in water up to 60 feet deep. Shallow water helmets of this type were phased out as SCUBA diving equipment became commonplace after World War II. Catch up with the series at https://lnkd.in/eDrN4JvV. (Image credit: Family of Captain David M. Whipp, U.S. Coast & Geodetic Survey)