Tuesday, May 31, 2005

Details on San Francisco Grounding Emerge

Originally posted 0926 15 Jan:

Robert Hamilton of The New London Day continues his series of articles revealing new light on the recent grounding of USS San Francisco (SSN-711). (Free registration required after one day.) An excerpt:

"In late morning, the ship was at periscope depth, checking to make sure it was on course. Everything checked out; the ship was just over 400 miles southeast of Guam, near the Caroline Islands ridge, but the charts showed that there was no water less than about 6,000 feet deep for at least seven miles around the boat, more than enough of a safety margin for submariners, who are known to be cautious.
"Some time about 11:30, after running through a safety checklist to make sure the boat was ready to submerge, the officer of the deck gave the order to dive. The San Francisco used the dive to pick up speed, and was soon running at flank speed, something in excess of 30 knots.
"Although its destination was to the southwest, it was headed in an easterly direction, probably because it had “cleared its baffles,” or changed direction to check to make sure there were no submarines trailing it in the spot directly behind the ship, where its normal sonar sensors cannot “hear.”
"At 11:42 a.m. Guam time, about four minutes after diving, the San Francisco crashed head-on into a nearly vertical wall of stone, a seamount that was not on the charts. In an instant, the submarine's speed dropped from almost 33 knots horizontal to 4 knots almost straight up as the bow whipped up and the ship tried to go over the obstacle — without success."

This article, while very informative, does have a few problems. Hamilton's use of the word "dive" in conjunction with the ship coming down from periscope depth (PD) is technically inaccurate; in submarine language, "dive" indicates a change in condition from surfaced operation to submerged operation, which is not what happened in this case -- the ship had been at a depth where it could stick its' antennae out of the water, and transitioned to a deeper depth. Also, his later discussion of "water space management" is inaccurate, but not enough to take away from the largely informative nature of the article. Read the whole thing...

Staying at PD...


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