Aiming to prevent any landings, and with no warships at his disposal, he equipped scores of chaloupes to defend the goulet and armed militias with weapons requisitioned by the navy. The cavalry regiments and dragoons were positioned at Landerneau and Quimper and, to enable the fast transmission of information, Vauban organised a communications code in the form of signals.
In an effort to thwart any potential landings, and without access to warships, he prepared numerous chaloupes for defense and equipped local militias with naval-issued arms. The cavalry units and dragoons were positioned at Landerneau and Quimper, and Vauban created a signaling system to expedite communication.