(Excerpt from “The Last Gun Ship - History of USS Mullinnix DD-944” - A Historical Novel By Frank A. Wood)
The dawn broke the horizon on 21 October to find the Mullinnix had stationed the special sea and anchor detail. With the assistance of tugs YTB 542, YTB 382, and civilian tug Athena she was underway for Dry Dock #1. By 0835 the caisson was in place and water was pumped out of the dry dock. By 0905 she was resting on the keel blocks.
A graving (versus a floating dry dock) dry dock is a narrow basin, usually made of earthen beams and concrete, closed by gates or a caisson, in which a vessel may be floated and the water pumped out, leaving the vessel supported on blocks. The keel blocks as well as the bilge block are placed on the floor of the dock in accordance with the "docking plan" of the ship.
Some fine-tuning of the ship's position can be done by scuba divers while there is still some water left to maneuver it about. Each ship has a diagram of the shape of its bottom. It is extremely important that supporting blocks conform to this shape so that the ship is not damaged when its weight is supported by the blocks. Some ASW warships have protruding sonar domes, requiring that the hull of the ship be supported several meters from the bottom of the dry dock.
Once the remainder of the water is pumped out, people can walk around in the dry dock, and the ship can be freely inspected or serviced. When work on the ship is finished, water is allowed to reenter the dry dock and the ship is carefully refloated.
To be continued…
Cheers,
Woody
