...Medium height of high-waters in the harbour : 4.92 m
Zero Level of French charts = - 4,43 m IGN 69 (as indicated by french Hydrographic Service)

At half-tide level , the sea reaches the bottom of the rock lying isolated in the southern part of the bay and carrying a green starboard mark.
The top of the rock is 7.3m above French charts zero level.

These levels, derived from nautical charts, should be used with caution as they may vary depending on the movements of the sandbanks.