Mare Island (WHTM) This is the story of how two work crews at opposite ends of a ship managed to sink a nuclear submarine.

The official report is a fascinating read.

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Launched in 1968, the U.S.S. Guitarro (SSN-665) was a nuclear-powered attack submarine undergoing her fitting out at the Mare Island site of the San Francisco Bay Naval Shipyard. She was scheduled for commissioning sometime in 1970.

Things didn’t go as scheduled.

On May 15, 1969, the two crews started to work on opposite ends of the ship. As for what happened next, I cannot improve on the Chronology of Events set out in the Official report:

During the afternoon and early evening of May 15, 1969, the following events occurred at the approximate times indicated:

4:00 P.M.: A civilian construction group (nuclear) began an instrument calibration assignment which required the filling of certain tanks, located aft of the ship’s pivot point, with approximately five tons of water.
4:30 P.M.: A civilian construction group (nonnuclear) began an assignment to bring the ship within a half degree of trim. This entailed the adding of water to tanks forward of the ship’s pivot point, to overcome a reported two degree up-bow attitude.
4:30 to 7:50 P.M.: The nuclear group continued to add water aft.
4:30 to 7:45 P.M.: The nonnuclear group continued to add water forward.
7:00 P.M. and again at 7:30 P.M.: A security watch advised the nonnuclear group that by that time the Guitarro was riding so low forward that a one and a half foot wave action, stirred up by boats operating in the river, was causing water to enter an uncovered manhole in the most forward and lowest portion of the ship’s deck. These warnings went unheeded.
7:45 P.M.: The nonnuclear group stopped adding water to the ballast tanks in preparation for their lunch break.

7:50 P.M.: The nuclear group completed their calibrating assignment and began to empty the tanks aft.
8:00 P.M.: The nonnuclear group left for lunch.
8:30 P.M.: The nuclear group emptying the water from the aft tanks and a member of the group noticed “sudden down angle being taken by the boat.” At approximately the same time, the nonnuclear group and others, returning to the ship from lunch, observed in down sharply at the bow with a massive flooding taking place through several large open hatches.
8:30 to 8:45 P.M.: Efforts made to close watertight doors and hatches were unsuccessful due to lines and cables running through them.
8:55 P.M.: The Guitarro sank.

The navy didn’t waste any time getting the sub back to the surface, refloating her on May 18, just three days after the sinking. The cost to repair Guitarro was estimated at 15.2 to 21.85 million dollars – about 125.64 to 180.61 million dollars today. She would be dubbed the “Mare Island Mud Puppy.”

The official report, compiled from over 600 pages of testimony, concluded the immediate cause of the sinking was “the culpable negligence of certain shipyard employees,” coupled with “inadequate coordination of both the ship construction activities and the assignment of specific responsibilities.”

Guitarro would finally be commissioned on September 9, 1972.

The Mare Island Mud Puppy apparently used up all her potential bad luck in the sinking. Guitarro would serve ably, conducting patrols and helping to test the Tomahawk missile system. She was decommissioned on May 29, 1992. 

The read the report on the sinking, click here.