More On Collision

Now we know a bit more about the collision between USS San Jacinto, an Aegis Cruiser and the nuclear submarine USS Montpelier. Montpelier came to periscope depth about 200 yards or less directly ahead of San Jacinto.

At that point, collision was inevitable. The Navy's report disclosed nothing about the damage to Montpelier, but revealed that San Jacinto's sonar dome was "completely depressurized."

The ships had been operating together in an antisubmarine exercise in the Atlantic. What this incident tells me is that both ships are extraordinarily quiet.

Typically, investigations of such collisions put the onus on the submarine to be sure there is no surface ship in the vicinity before coming to periscope depth or surfacing. But what if the surface ship is extremely quiet? Was San Jacinto operating too slowly to be detected? Were the two vessels communicating? Why did San Jacinto not detect the submarine when it was less than a mile away? Lots of questions.

As for the sonar dome, that will be an expensive repair. One of the challenges the Navy faced with the large multi-mode sonar installations beginning with the AN/SQS-26 series of sonars was that the self-noise of water rushing past the dome reduced the sonar's sensitivity. The problem was the steel "window" surrounding the transducer. In 1976 my ship, USS Patterson, received one of the first inflatable rubber sonar domes. This was not a simple modification.

I expect repairs to San Jacinto will prove to be expensive and time consuming.