sorry, couldn't remember this earlier, but there are a series of books called "coast pilot" from noaa. they are specific to areas around the country.

from the website:

http://nauticalcharts.noaa.gov/nsd/coastpilot.htm

"Issued in nine volumes, they contain supplemental information that is difficult to portray on a nautical chart.

Topics in the Coast Pilot include channel descriptions, anchorages, bridge and cable clearances, currents, tide and water levels, prominent features, pilotage, towage, weather, ice conditions, wharf descriptions, dangers, routes, traffic separation schemes, small-craft facilities, and Federal regulations applicable to navigation."

they might have fog horn frequencies and durations, i seem to remember that they do.

invaluable - along w/charts and gps - when sailing to areas unknown.