The 51-year-old, 946-foot naval vessel named the Denebola was having a problem with its steering pump just north of the Bay Bridge’s two spans — which carry about 80,000 vehicles per day ...

The Key Bridge, built in the 1970s, was never tested by those modern standards. Until now, neither was the Bay Bridge, which opened its eastbound span in 1952 and its westbound span in 1973.