Working Under Water

Working Under Water. . One of the greatest construction challenges took place underwater. The south tower was located more than 1,100 feet (335 meters) from the San Francisco shore. To build the south tower structures, divers played a critical role descending up to 110 feet (33 meters) into the tumultuous waters of the Golden Gate Strait. They placed dynamite charges and removed loose material down to bedrock with high-pressure hoses. Later, they descended to guide the positioning of the forms and funnels used to place the concrete for the south tower fender., Divers worked in water that was dark, murky and cold, and only when the tide changed and the usually strong currents lessened, which occurred four times in a day. Portable air tanks for diving had not yet been invented. A diver’s life depended on the continuous pumping of air through a long hose to the surface., Captions (left to right): , . Divers in their heavy gear, prior to putting on helmets. San Francisco History Center, San Francisco Public Library , . If a diver surfaced too quickly, air bubbles could be released into the bloodstream, a condition called "the bends." Decompression chambers were kept nearby just in case. San Francisco History Center, San Francisco Public Library , . Workers load explosive charges into a framework that is then lowered to the seafloor and positioned by divers. San Francisco History Center, San Francisco Public Library ,