Built by the China State Shipbuilding Corporation, each OPV cost about US$50 million. The vessels, each with a maximum displacement of 1,635 tonnes, were commissioned in 2006-2007 and make extensive use of COTS technologies to keep the acquisition and maintenance costs low.
Each OPV has a length of 95.5 metres, beamwidth of 11.6 metres, displaces 1,440 tonnes, is crewed by a complement of 84 personnel, and is powered by twin Rushton 16RK270 diesel engines driving twin controllable-pitch propellers.
The armaments package comprises one OTOBREDA 76/62 main gun and twin 40mm secondary guns. Both OPVs also feature one rear helicopter deck capable of housing helicopters like the AgustaWestland-built Super Lynx Mk300.
The OPVs’ combat management system is STN ATLAS of Germany’s COSYS Mk1, which was selected in June 2003. STN Atlas was also the overall systems integrator. The fire-control systems include one TMX supplied by Oerlikon Contraves AG. Rohde & Schwarz has supplied the integrated communications system, while Raytheon Marine GmbH’s integrated platform and machinery management system has been installed. SELEX Sistemi Integrati was selected in April 2003 to supply two X-band RAN 30X/I mast-mounted naval surveillance radars worth Euros 6 million.
The RAN 30X/I has four operational modes: surface and air surveillance mode for small airborne/surface targets; navigation and helicopter control mode with high antenna rotation speed for navigation close to the coastline; over- the-horizon detection mode with low- antenna rotation speed and long-range detection capability; and anti-sea- skimming cruise missile detection mode, with high-antenna rotation speed to detect and track very small manoeuvring targets.
(data: INDIA DEFENCE)
Beegeagle's Blog 
I came across these (old 2009) news about FG plan to replace Aradu with a bigger more modern ship by 2014 http://ndn.nigeriadailynews.com/templates/default.aspx?a=18265&template=print-article.htm can anyone confirm this story or if the plan is still on course?
They should consider buying one 6,600 ton Absalon-type ship and two Fassmer 80 OPVs and a Makassar-class LPD for a combined outlay for US$400 million OR
a Type 054A area defence frigate, two Fassmer 80 OPVs, a Makassar-class LPD and two upgunned Damen 8313 ORPVs for US$400 million.
At the time when that report was published, some European shipbuilders were offering two warships for US$800 million. That was crazy…absolutely ridiculous proposition. We need to match quality with quantify to be able to saturate our EEZ whereas two frigates are just that..TWO platforms and that does not go far enough.
For US$800m, I would build an instant navy for Nigeria which would have a new flagship that would be as powerfully armed as the NNS Aradu PLUS two LPDs, eight OPVs, eight ASW helicopters, six missile-armed 32 metre OCEA patrol craft and nine Shaldag Mk.II FPCs.
The HTMS Pattani is in Manila right now…together with HTMS Bangpakong ang HTMS Chao Phraya (Type 052 frigates)..all 3 are Chinese made ships. The Pattani is an example of how Chinese hulls can be integrated with Western, sensors and weapons systems. So far havent heard much about its performance or build quality but was said to be better built than the older Chinese frigates.