The Greek-registered MV Flag Theofano capsized in heavy seas on the night of 29 January 1990.
All 19 crew members died, although only five bodies were found.
The stone at Kingston Cemetery in Portsmouth marks the grave of Ibrahim Hussain – the only victim of the tragedy to be buried in the UK.
The Greek-registered vessel, which had been carrying a cargo of cement from Le Havre to Southampton, had been instructed to anchor in St Helen’s anchorage, off the Isle of Wight, as it waited to dock but the following morning contact with the vessel had been lost.
The upturned ship full of cement was later located 20 metres below the surface, near Dean Tail buoy – east of the anchorage.
Four of the five bodies recovered were returned home to Greece for burial while Mr Hussain was buried in the Muslim section of Kingston Cemetery.
The headstone, installed by Portsmouth City Council, was funded by the Southampton Shipowners’ Association as well as people involved in the search operation or the local shipping industry at the time.