Vertical Clearance Calculator

Highest Astronomical Tide for this location

Predicted tide height when you arrive

Highest point above waterline

Additional clearance buffer

How to Use

  • • Enter bridge clearance height at HAT (from charts)
  • • Input the HAT value for your location
  • • Enter predicted tide height at your arrival time
  • • Input vessel air draft and desired safety margin
  • • Calculator determines if passage is safe using HAT methodology

⚠ Safety Notice

This calculator uses HAT-based methodology for planning purposes only. Always verify with current charts, tide tables, and local authorities. Consider wave action, vessel squat, and other factors.