The waters of the neighbouring East Float were held back from the entrance channel by a 200-foot-long (61 m) temporary coffer dam, formed from pilings rammed with mud and cement, which had been built in 1907.
At around 12:25 am the foundation of the coffer dam gave way without warning; the fifteen workers were overwhelmed by water and debris.
[2] A platform carrying the crane, engine and boiler collapsed into the excavation, and, it is believed, trapped the men underwater.
At the ensuing inquest, John Scott's chief engineer claimed that the disaster was probably caused when the base of the coffer dam shifted after pilings from the old dock wall were removed, and this event could not have been foreseen.
But his evidence was disregarded and the jury, heavily influenced by the coroner's summing-up, returned a verdict that no one was to blame.