At first glance, viewed from the Bay Bridge or a downtown high-rise, San Francisco Bay looks empty. Drivers might notice a container ship passing under the bridge sometimes, a ferryboat coming or going on the waterfront. Or they might glance south of the bridge and notice 10 or so big ships anchored, not moving, waiting for a berth or sailing orders, like a maritime parking lot.
Maritime traffic is not on the radar of most Bay Area residents. Unless, of course, something bad happens — a ship collision, an oil spill.
In a windowless room on the second floor of a nondescript building at the Coast Guard’s San Francisco sector base on Yerba Buena Island, a handful of men and women are on duty 24/7 to prevent that from happening.
They are traffic management specialists at the Coast Guard’s vessel traffic service, orchestrating the movement of ships and large boats on San Francisco Bay and its tributaries, as well as the sea approaches to the Golden Gate.
It’s huge: The edge of their territory runs 40 or so miles into the Pacific from the Golden Gate, then easterly through San Francisco, San Pablo and Suisun bays up through the maze of islands and channels in the Sacramento-San Joaquin River Delta as far as the Sacramento and Stockton deepwater ports. It’s an area of about 4,500 square miles of seaway and the land in between — the heart of one of America’s largest ports.
It’s like a slow-motion chess game. The chess pieces are big, and the board is complex. The big container ships are the size of high-rise buildings. The smaller vessels are the fast ferries that skitter across the bay like bugs.
There are 10,000 to 12,000 transits a month on the bay, according to Robert Blomerth, director of the Coast Guard’s San Francisco sector’s Vessel Traffic Service.
“It’s an amazing number,” Blomerth said “A lot of moving parts.”
The container ships bring in the supplies we use in everyday life — clothes, automobiles, frozen fish, beer, toilet paper, electronic goods. In the famous phrase, 90% of everything comes by sea. So does crude oil, which arrives by tanker ships to be refined in five Bay Area facilities. They produce gasoline, even jet fuel, moved to the airports in underwater pipelines.
So the maritime trade is important, and so is the traffic center that monitors and controls all this. The Coast Guard personnel who run it spend their shift in a room lined with electronic charts and displays that show the bay and the sea approaches in startlingly close detail.
Every vessel that carries an automatic identification system tracking device shows up on the charts, even if the vessel is anchored or tied to a pier. The tracking device shows the ship’s name, length, width, draft, course, speed, intended destination and much more.
The vessels are shown as yellow dots that move. There are also red markers that indicate problem areas — “like cone zones on a freeway,” said Scott Humphrey, training director for the Vessel Traffic Service. The charts also show underwater pipelines and BART’s Transbay Tube. There are choke points where bridges cross the bay and the channels are narrow. The most famous is the Golden Gate strait. The most troublesome is the Union Pacific Railroad drawbridge between Martinez and Benicia, where passenger and long freight trains must stop when the bridge is raised for passing ships.
In a typical operation for a large ship sailing outbound, the pilot, a master mariner who will navigate the ship out of the bay, will contact the Vessel Traffic Service on VHF radio channel 13. The pilot will give his identifying number, the name of the ship, the ship’s location, usually Oakland, and destination: bound for sea is the usual call. The pilot will usually tell traffic his intended route through the bay — where he intends to cross under the Bay Bridge, which traffic lane the ship will use in the central bay — and any other useful information. The vessel traffic center will tell the pilot about inbound traffic, including ships, ferries and work vessels and go-slow zones. On a clear day this is all easily seen, but in fog and on that legendary dark and stormy night, every piece of information counts.
In fact, the San Francisco Vessel Traffic Service began in a winter fog in 1971 when two tankers collided near the Golden Gate Bridge. At that time the region had an experimental traffic radar, but ships were not required to monitor the traffic service. It was a kind of voluntary advisory operation.
The two ships were on a collision course, and the radar service broadcast a warning. Only one ship heard the warning; the other was not tuned in. The radar traffic service was there, “but was unable to prevent it from happening,” Humphrey said.
Both ships were carrying crude oil — and 800,000 gallons leaked into the water. There was a huge outcry. Hundreds of Bay Area citizens volunteered to help with the cleanup, but thousands of seabirds died.
The next year, Congress passed legislation establishing a San Francisco Vessel Traffic Service with mandatory participation by all commercial shipping. The service will celebrate its 50th anniversary with a small ceremony in November.
Carl Nolte’s columns appear in The San Francisco Chronicle’s Sunday edition. Email: cnolte@sfchronicle.com
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