Bridge Clearance Checker
Compare a measured NOAA air gap with the height your boat needs. The result is a transparent margin calculation — not a navigation authorization.
Ready for a live observation
Choose a station and run the check. NOAA data will appear here with its observation time.
Navigation check: BoatWaypoint is a planning aid, not a substitute for official NOAA charts, USCG Local Notices to Mariners, bridge operator instructions, on-water judgment or a chartplotter. Air-gap observations may be preliminary and are measured at a designated reference point.
What the margin means
A positive planning margin means the latest reported air gap at that NOAA reference point exceeds the height you entered plus your chosen buffer. A zero or negative margin means it does not. Neither outcome proves the entire bridge span or your exact track is passable.
Why air gap can change
Water level, wind setup, river flow, atmospheric pressure and local bridge geometry all matter. Your vessel height can also change with loading, antennas, outriggers or equipment. Measure the boat, do not rely on a brochure number alone.