Check out:

http://www.navcen.uscg.gov/marcomms/gmdss/epirb.htm http://www.navcen.uscg.gov/marcomms/gmdss/epirb.htm

Water ballast - I seem to remember a scene on a Hobie video of a 16 regatta in high wind, and there's a guy getting ready to go sailing with a bunch of plastic jugs filled with water hanging from his body....