Lock down your true air draft
Measure to the highest fixed point in the loaded configuration you will actually run. Write down what folds, what does not, and the buffer you refuse to consume.
Florida ICW: plan the bridge sequence, not just the next bridge.
The Intracoastal Waterway turns air draft into a recurring decision. Use this workflow to reduce surprises while keeping official charts and bridge notices in charge.
Build a bridge list
For each planned leg, identify fixed and movable bridges from current official charting, not a crowdsourced height list. Flag the lowest fixed point and every opening restriction.
Use direct air-gap data where it exists
A NOAA air-gap sensor is stronger than guessing from a nearby tide station because the observation is tied to a bridge reference point. Coverage is limited, so absence of a sensor is not absence of a bridge constraint.
Time tide-sensitive legs carefully
When you use a tide prediction, keep its datum visible. Verify whether the bridge clearance reference is compatible before converting water-level change into estimated clearance.
Check operations and notices
Movable bridge schedules, temporary restrictions, maintenance and navigation notices can override the neatest calculation. Confirm the current rule for the actual date and time of passage.
Keep an escape option
Do not make a tight theoretical margin your only plan. Know where you can wait, turn around or hold safely if conditions or bridge operation differ from the plan.
Useful now
Check a NOAA-supported bridge or your next tide window.
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.