The US Coast Guard has a terrific Boating Safety website. Never go to sea unprepared! Visit this site and make sure you know how to boat safely and what to do in case of an on-the-water emergency.
The National Oceanic and Atmospheric Administration (NOAA) is a good resource for the Tide, Water Level, Temperature, WInd information you need to make it safely to your destination or win that race. Remember: Be safe; FIle a Sail Plan.