The (Ancient) Admiral Class frigates were the first successful domestic frigate design, succeeding the previous destroyer escorts of (Ancient) General Class. They were designed mainly for Aegean and Black Sea, with quite heavy armament for their size and COGOG propulsion based on British Type 14M frigates for quick reaction time. Hellenic Kingdom was interested from very early for the Rolls Royce Olympus Gas Turbine and built them under license for many years, by the Hellenic Turbines Factory in Piraeus. Initially 20 were built for RHN and 4 for Cypriot Naval Command, plus a derivative patrol vessel with CODOG propulsion for Hellenic Coastguard, the "670" Class OPV. These were numbered from 670 to 679 and named from Coastguard officers who died in WW2. Finally, Hellenic Frontier Guard also received the OPV variant. Four shipyards built the "Admiral" family from 1965 to 1989. Despite export interest, only Malaysia adopt the design, ordering 4 in early 1980's. Some were sold second hand in Latin American countries in 2000's and in Black Sea countries, while other converted to OPVs and remained in Hellenic waters. All ships feature a semi-sliding hangar (not telescopic) and a large helipad for their size. Helicopter on board in the beginning was the Alouette III (of which around 200 were built under license in HLK and used by Army, Navy and Police Forces from 1964 to 1980), later AB-204 and finally AB-212. The venerable Alouette III in still in service under RHN Flying School, several were modified for training missions. Note that the helipad was found just large enough for AS-332C Super Puma and therefore all Coastguard and Frontier Guard OPV variant had their helipads strengthened. Some were fitted with domestic AESA medium range radar, other retained their original targeting radar but with upgraded electronics. The AWS-1 was replaced by a domestic 2D long range radar during their MLU. Admiral Class frigates were also the first large surface units of RHN fitted with the domestic HSSM-1 missile, an analog of Norwegian Penguin with IR or TV guidance and 120 kg warhead.
Cypriots converted themselves their King class frigates (all named by Ancient Cypriot Kings) into OPVs, replacing the missiles with twin hellenic origin RHIBs and fitting an hellenic RWS with Aden 30mm cannon double ended, also torpedo tubes removed. They retained the EW systems, sonar and the COGOG machinery. Cypriot Marine Police also uses Alouette III for training.
Dimensions : 98,6 x 11,8 x 3,5 (m)
Displacement : 1.650-1.770 tn
Propulsion : (Frigate) COGOG, 2 x 4,250 hp Bristol Proteus 15M (after MLU 2 x Allison 501KF 4,500hp in all 24 frigates) plus one Olympus TM1B or TM3C gas turbine (1 X 22,300 hp or 29,600 hp)
(OPV) CODOG, 2 x ADC/GM 16-630C/D two-stroke diesels plus the Olympus
Range: 4,250-5600 nm at 16kn (4,800 nm with Allison KF501)
Speed : 27,5-30+ kn (max)
Aviation facilities: Hangar and helipad for medium helicopter