Raz de Sein

This tidal water is an essential passage for vessels wishing to pass between the Atlantic and the English Channel, because further west at high tide the Isle of Sein and its embankment stretch for more than thirty miles.

The current causes the sea to rise quickly, and it is recommended that heavy vessels should only attempt to cross this strait at still water during calmer conditions.

Notably, during the Expédition d'Irlande, on 16 December 1796, the Séduisant foundered as the French invasion fleet sailed through the Raz de Sein at night in stormy weather in an attempt to avoid the blockading ships.

On May 26, 2006, Édouard Michelin died while fishing for sea bass on his ship Liberté.

The boat was found two days later with no apparent damage, 70 meters deep and roughly 15 km from the Île de Sein.