Crossing dry-shod

This happy family group are posing inside a six-foot wide pipe at Clontarf in 1925. The pipes were used in the Middle Harbour syphon scheme, a massive engineering project for the period. Two parallel rows of concrete pipes, ten-inches thick, were laid under the waters of Middle Harbour from Clontarf to Mosman. Tremendous feats of diving endurance were undertaken by the workmen on the project, with spells underwater of up to seven hours, thought to be a world record at the time. In places the pipes were seventy feet below the surface. The job took close to two years to complete, and over the course of construction strange coralline growths sprang up and adhered to the inside of the pipes.

When the job was complete, an open day was held in December 1925, when, for sixpence, you could walk along inside the pipeline across from one side of Middle Harbour to the other - without getting your feet wet. That's a trivia quiz question waiting to be asked. Aptly, the money raised went to the benevolent fund of the workmen who had performed the feat of laying the pipes.