Brueys sent the aviso Alerte across the British approach in hopes that pursuers would ground on the shoal. The ruse failed because British captains were looking for the distinctive night identifiers Nelson had ordered. Alerte's lack of an illuminated white ensign and four horizontal lights effectively advertised that it was not part of the British line. Preparation for mutual recognition defeated an improvised attempt at deception before the main lines met.
Notable Point · 1:41:37-1:45:17
The French decoy fails against Nelson's identification system
A French vessel tried to lure the British over a shoal, but Nelson's prescribed lights and ensigns made the decoy easy to distinguish.