After further broadcasts and threats, the defenders answered with coastal-battery fire and positioned Richelieu so that its forward guns could engage. Guns taken from the semi-dreadnought Vergniaud added 12-inch and 9.2-inch weapons to the defensive problem, although sources disagree over how much of the secondary battery went ashore. The submarines Persée and Ajax also sortied, with Persée attempting a conspicuous surface approach toward Barham. British signals asking why the French were firing produced demands that the fleet retire rather than a renewed negotiation. Barham's reply with 15-inch guns turned a political demonstration into a high-risk naval engagement around a fortified harbor.
Notable Point · 26:17-31:07
Coastal batteries bring the fleet under fire
The failure of negotiations led to an artillery duel involving shore batteries, Richelieu's forward guns, submarines, and Barham's heavy artillery.