A Navy submariner has pleaded guilty to charges he improperly possessed defense secrets and stole government-owned computer hard drives, which he later sold on the Internet. Petty Officer 1st Class Bryan Moody was sentenced Friday by a military judge to seven months in the brig and loss of pay. He also was reduced to seaman recruit. Moody was an electrician´s mate formerly assigned to the submarine Helena at Point Loma Naval Base. Prosecutors agreed to a plea deal in exchange for Moody´s cooperation in determining whether military secrets were compromised. Navy investigators found dozens of computer diskettes with secret information about nuclear reactors and submarine options at Moody´s San Diego home and at his ex-wife´s residence.