Choose your study region

Choose a course collection, not your nationality. Changing region does not change your courses, progress or access.

Compass network home

Optional preference saved in this browser on Compass Revision. It does not sync between devices or the separate course websites. You are never redirected automatically.

All questions
Tides

How do you calculate tidal height for a simple depth check?

Short answer

Add the height of tide to the charted depth, then compare the result with draught plus a safety margin.

For a basic under-keel clearance check, use charted depth plus height of tide to estimate available depth. Then subtract vessel draught and keep a margin for uncertainty, movement, and local conditions.

Sources and scope

Reviewed by Richard Moore on . This answer is scoped to united kingdom and general recreational seamanship; check the current chart, publication, local rules and official operational guidance before acting afloat.

Quick check

How do you calculate tidal height for a simple depth check?