Many ocean going vessels operate on HF bands and use satellite radios, none of which are accessible by most scanners. There are standard VHF frequencies/channels used by many boaters and ships though, and you can follow the link below for a complete list of them:
http://www.navcen.uscg.gov/marcomms/vhf.htm
One can find a list of scanner frequencies on Radio Reference. Depending on where the person is, the site let's one pinpoint a locations to find scanner frequencies.
Check out the radioreference.com website they should have any and all scanner frequencies you could want.
Radio Shack sells booklets with frequencies for public and some private agencies nationwide. There may be lists on the Web as well. Try Googling "scanner frequencies."
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com
For a comprehensive database of active frequencies in your area, visit: www.RadioReference.com