House flag of Derca
Derca is a Belgian inland gas tanker operator based at Antwerp. The Binnenvart website gives the company's years of activity as 1980-1991, but the Shamal was launched in 2007.
Derca was taken over by Chemgas in the beginning of the nineteen eighties, but that firm is itself now, after an outing with Vopak, owned by Jaegers.
The Shipspotting weblog shows Shamal (first photo of 17 December 2007), flying a flag horizontally divided red-white-red (1:2:1) like the municipal flag of Antwerp and bearing the company's name DERCA in black letters (no serifs) on the central stripe.
A table flag was offerred on German eBay in January 2008, with dimensions given as approximatively 15 cm x 23 cm. Black letters are one third of flag height