The NATO Standing NATO Maritime Group 1 consisting of F-805 HNLMS Eversten and FGS F-208 Rheinland Pfalz has left Istanbul on 25 May 2012. They will stop at Aksaz Naval Base in Marmaris, before heading to Gulf of Aden to continue NATO’s anti piracy operation, Operation Ocean Shield.
But as the photo above show we have a new visitor: the Brazilian Niterói Class Frigate F-45 BNS União.
From November 2011 till this month, she was the flagship of Rear Admiral Luiz Henrique Caroli of Brazil, the Commander of the UNIFIL-MTF which is assisting the Lebanese Navy monitor Lebanese territorial waters. Another Niteroi class frigate F-43 BNS Liberal has replaced her in UNIFIL. The Brazilian sailors are doing a well earned port visit in Istanbul before departing for a long voyage to home.
devrimyaylali.com 
Brazil is confusing for prefixes. BNS doesn’t apply, each type of ship has its own prefix. http://www.seawaves.com/prefixes.asp
Notice some countries don’t want to give up the 26ft US style whale boat in davits. Two RHIBs mounted a stern.
Dave is right. The prefix BNS is not an official, at least not known in the Brazilian Navy. Where the prefix depends on each typ of ships, such as :
frigat = F
aircraftcarrier = NAe (from the Port. Navio Aerodomo)
So in this case what is the correct nomenclature? F-45 F Uniao?
Interesting. I would think each navy would put their name (like TCG) to distinguish the nationality. After looking Portuguese version of wikipedia, it is indeed referred as F Uniao. Others can be found at
http://pt.wikipedia.org/wiki/Lista_de_navios_constru%C3%ADdos_no_Arsenal_de_Marinha_do_Rio_de_Janeiro
http://pt.wikipedia.org/wiki/Lista_das_embarca%C3%A7%C3%B5es_da_Marinha_do_Brasil
Thanks mcpon for enlightening us.