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![Early hard hats were heavy in air, but buoyant underwater nur06013.jpg Early hard hats were heavy in air, but buoyant underwater](/sites/default/files/styles/max_1300x1300/https/s3.amazonaws.com/s3-east-testmedia-noaa.woc.noaa.gov/dam/Photos/legacy/pl23_nur06013.jpg?itok=CYA2nxiu)
Description
Early hard hats were heavy in air, but buoyant underwater. (Image credit: OAR/National Undersea Research Program (NURP))
Credit
OAR/National Undersea Research Program (NURP)
Collection
Voyage to Inner Space
National Undersea Research Program (NURP) Collection
Undersea Technologies
Tethered Drivers
Keywords
Undersea Technologies
Tethered Divers