Tuesday, May 31, 2005
Christopher Drew of the New York Times rebounds from a controversial (at least within the submarine community) earlier story on the San Francisco grounding with a useful and informative article on the possible shortcomings of the charts being used by the Submarine Force (annoying free registration to get the second page of the article). Here's the money shot:
"The submarine had crashed head-on into an undersea mountain that was not on the charts. One sailor was killed, and about 60 others were injured. Now, Defense Department officials say they have found a satellite image taken in 1999 that indicates an undersea mountain rising to perhaps within 100 feet below the surface there.
"But the older navigation charts provided to the Navy were never updated to show the obstruction, they acknowledge, in part because the agency that creates them has never had the resources to use the satellite data systematically.
"The officials said the main chart on the submarine, prepared in 1989 and never revised, did not show any potential obstacles within three miles of the crash. They said the incident happened in such a desolate area - 360 miles southeast of Guam - that updating their depiction of the undersea terrain was never considered a priority.
"The new information about the charting flaws also illustrates what many experts say is a broader danger not only to submarines but also to many surface ships. At the same time, it provides a glimpse into the arcane task of plotting an undersea world that in some areas is still more mysterious than the surfaces of Mars or Venus."
There are lots of areas left in the world where the charts will show only a few narrow tracks where sounding (water depths) have been taken, and a lot of blank space. What we're finding out here is that even if your chart seems to be full on information, there's a lot going on under the water that we don't know about....
Update 1651 15 Jan: Here's a website that gives a general view of mapping the seafloor by satellite.