Marco is right in his identification, but the full explanation is given by Aris Bilalis in a topic in forum-marinearchiv:
http://www.forum-marinearchiv.de/smf/in ... 984.0.html
"First of all, the four Italian-built chasers, were not originally named A1-A4 but D1-D4 (Δ1-Δ4). Τhe letter "Δ" potentially meant "Διωξης"=Chaser. Under these names they were delivered to the Greek Customs, a department of the Greek Ministry of Finance, and operated in anti-smuggling duties. Hence, as they were not warships, they were registered like civilian ships are.
Attached (no.1) is a photo of D1 taken in Ithaki Island. One will note that the ship is not flying the Greek flag but the Italian flag which was apparently used for the delivery voyage. The assumption that the photo was taken during the delivery reason justifies why she has that extra barrel on the stern deck (for additional fuel) and why all these people are on board (visitors for the new vessel).
Secondly, when the ships were transferred from the Customs' to the Navy they took the names F (Φ) 1-F4. They were then renamed A1-A4 and are mentioned as such all the way until their loss."
The picture mentioned by Aris is the same posted by Alain in his question.
Cordialement
Klaus Günther
