Scanning the slate-gray waters of San Francisco Bay on an overcast spring day I spot more eider ducks and gulls than barges or ships. We're patrolling past Alcatraz in a 41-foot Coast Guard utility boat that's almost as old as its blue-eyed 30-year-old coxswain, Chuck Ashmore. Ironically, this old workhorse, with its aging marine radio and soon-to-be-installed Vietnam-era .60-caliber machine gun, is on the cutting edge of a revolution in homeland-or, I should say, home water-security.