The P400 patrol ships are small vessels of the French Navy. They were designed to accomplish police operations in the large French Exclusive Economic Zone.

The P400 were built by the Constructions Mécaniques de Normandie, which specialise in small military craft (they also built the Combattante, two swift "Patra" patrol boats, and numerous Combattante I and Combattante III missile attack craft).

Two similar ships are in service in Gabon.

The P400 were originally designed in two versions: one armed with Exocet MM38 missiles, and another public service version with a smaller 16-man complement; eventually neither of these versions was commissioned, the Navy choosing an intermediary version.

Most of these craft are pre-positioned in overseas territories (DOM/TOM) where they carry out sea monitoring missions and secured the EEZ. They also execute missions in the context of French agreements with other nations, typically supporting foreign armies or carrying out humanitarian missions.

Technical Problems

The engines of the P400 have been a constant source of technical problems since the maiden journey of the lead ship Audacieuse to Dakar.

The first problem that occurred related to the carter reductor, then with the transmission, and eventually with a piston -- this last item being the most worrying, since it was probably a symptom of a conception problem. This shed a bad light on Alstom who were trying to compete against German motors by MTU. French humourist Coluche came up with the witty remark Après l'Audacieuse, la Boudeuse, la Capricieuse,… voici venu le temps de la Dépanneuse ! (After the Audacieuse, the Boudeuse, the Capricieuse, time has come for the Wrecker!).

After these problems were solved, larger exhaust pipes had to be fixed (originally, exhaust was vented underwater to minimise infra-red signature, but it turned out that the ship was taking water from these openings).

Transport capacity

After further studies, it became possible to gain the space of one propulsion compartment, which is now used for cargo and personnel. The ships can ferry 20 people, and up to 60 for short travel with a calm sea.

Crane

The P400 are fitted with a hydraulic crane capable of lifting 2,5 tonnes. This allows to use them for anti-pollution operations, by embarking and debarking equipment and anti-pollution chemicals, and to lift out small craft whilst at sea.

Operational Centre

An unusual feature for ships of this size, the Operational Centre allows a complete monitoring of close surface situations, using radar indicators and tracking tables.

Reduced complement

The engine can now be monitored remotely, which allows for a smaller crew. The maintenance of the ship was simplified notably by choosing those solutions which allow to clean the ship whilst in populated areas.

Autonomy

The P400 can stay 15 days at sea, and have 20 days of food supplies for 28 men.