Notes linked to Jerry A. Whitworth and found in the home of Soviet spy John A. Walker when he was arrested last year would have enabled Russia to pinpoint American naval strengths, predict the locations of specific ships and win a sea war with the United States, the officer in charge of Atlantic fleet communications testified in Whitworth’s San Francisco federal court trial. “It staggers me that there is that kind of information on this sheet,” said Capt. David L. Ricketts. Whitworth, 46, a retired senior petty officer and communications specialist, is charged with 13 counts of espionage and tax evasion. He allegedly was a member of a spy ring headed by Walker inside the Navy. He is accused of selling Walker diagrams of military cryptographic machines as well as the key lists making it possible to alter codes daily.