The ''D'Estienne d'Orves
-class avisos were primarily designed for anti-submarine warfare (ASW) in coastal areas and colonial coastal patrol. They were ordered as replacements for the E 50 and E 52 type escorteurs'' of the
French Navy. The ships are built austerely and have a
standard displacement of and at full load. The avisos are
long overall and
between perpendiculars with a
beam of and a
draught of . The avisos are propelled by two shafts turning
controllable pitch propellers powered by two
SEMT Pielstick 12 PC 2 V400
diesel engines rated at . The two engines are located in a single engine room mounted next to each other and controlled from a room abaft the machinery room. The two diesel engine system was selected due to the preference of endurance over speed. The ''D'Estienne d'Orves'' class has a maximum speed of and a range of at . All ships in the class are fitted with
fin stabilisers except for and . The class was intended to be constructed in two groups, the A 69 and A 70 types, with the latter type fitted with two
Exocet MM38
surface-to-surface missiles (SSM) on either side of the
funnel, but in the end, all ships of the class were fitted with the SSMs. The ships are armed with a
CADAM gun turret with Najir fire control system and CMS LYNCEA, a pair of
modèle F2 guns and four machine guns. For ASW operations, the ''D'Estienne d'Orves'' class mounts four fixed catapults for L3 or L5 type
torpedoes with no reloads carried and one remote-controlled sextuple
rocket launcher, with 30 reloads carried in a
magazine located beneath the aft deckhouse. The ''D'Estienne d'Orves'' class is equipped with one air/surface DRBV 51A sentry radar, one DRBC 32E fire control radar one Decca 1226 navigation radar and DUBA 25 hull-mounted sonar. The DUBA 25 is situated in a fixed dome with a retractable transducer, but is designed strictly for use in coastal waters. As countermeasures the avisos have one ARBR 16 radar interceptor, two Dagaie decoy launchers and one
SLQ-25 Nixie countermeasure system, which was fitted in the mid-1980s. The ships have a complement of 90 and have space to accommodate 18 marines.
Modifications Beyond the Nixie countermeasure system, the funnels aboard the avisos were heightened due to issues with the gases coming from them. had SEMT Pielstick 12 PA 6 BTC diesels with infrared suppression systems installed which led to delays into the vessel's entry into service. In 1993, and had their rocket launchers removed and a Syracuse II satcom terminal installed. Plans were drawn up to give the two ships a
hangar and
flight deck for helicopters, but this was abandoned. From 2009, the remaining vessels in French service were reclassified as
offshore patrol vessels (OPVs) and, as a result, had their surface-to-surface missiles and heavy anti-submarine weapons removed. Replacement of these vessels in French service is currently planned starting from 2027 by a new class of patrol vessels. == Ships in the class ==