Bridge Procedures
Traveling the inland waterways can be a pleasant experience but can also bring some special challenges, especially for larger boats and sailboats. Dealing with drawbridges takes some knowledge of how the system works and knowing what you are looking for, especially at night.
Nautical charts only tell you that there is a bridge and what the horizontal clearance (width) and vertical clearance (height) are. The vertical clearance is the one you are probably going to be most concerned with, i.e., will you fit under the bridge or will you have to open it? You should consult your chart for the note on heights; most will show minimum vertical clearance at mean high water. That means if you are at the bridge at any time other than high tide, you should have more clearance than shown. (You'll be able to tell exactly when you get there.) You should, prior to planning a trip, consult the coast pilot or cruising guides for the area you will be traveling and make notes in your trip log concerning bridges including name of bridge, hours of operation, recommended method of contact, etc.
As you approach a bridge there are several things that you should look for. You should check the right side of the bridge opening for the "clearance board." This will give you the minimum clearance, in feet, from the water level to the bridge structure. This will determine whether you can clear the bridge or will need to have it open. Speaking of opening a bridge, you should know the vertical height of your boat prior to getting to the bridge. Do not cause unnecessary openings, it is illegal!According to U.S. Coast Guard regulations, you may be subject to both criminal and civil penalties for causing an unnecessary bridge opening because of "any nonstructural vessel appurtenance which is not essential to navigation or which is easily lowered." In other words if the only thing making you open the bridge is your VHF antenna or outriggers, take them down. These same regulations also provide penalties for any bridge tender who "unnecessarily delays the opening of a drawbridge after the required signal has been given."
