Working Under Water

One of the greatest construction challenges took place underwater at the south tower, which stood more than 1,100 feet from the San Francisco shore. Divers played a critical role in building the south tower structures, descending as deep as 110 feet into the tumultuous waters of the Golden Gate Strait to place dynamite charges and remove loose material down to bedrock with high-pressure hoses. Later, they descended to guide the positioning of the forms and funnels used to place concrete for the south tower fender. They worked in dark, murky, cold water and only when the tide changed and the usually strong currents lessened, which happened four times a day. Because portable air tanks had not yet been invented, a diver's life depended on the continuous pumping of air through a long hose to the surface. If a diver surfaced too quickly, air bubbles could enter the bloodstream, a condition called the bends, so decompression chambers were kept nearby.

San Francisco, California · United States