Ships and Marine Cinderella stamps

The Great Bitter Lakes Association

The Six Day War of 1967 caused the closure of the Suwz Canal by Egypt. In a few days israel had taken possession of much of Sinai, right up to the banks of the canal, and significantly today, Gaza.
15 freight ships from 8 countries were left trapped, anchored in Great Bitter Lake, part way along the canal. These ships were named the Yellow Fleet because they became covered with sand. They remained there until after the Yom Kippur War in 1973 with Egyot reclaiming much lost territory, after which it still took two more years for mines to be removed and scuttled ships lifted out and other obstructions taken away. The ships though remained manned, though with skeleton crews and periods of rotation aboard. The Great Bitter Lake Association was formed. Crews organised yacht races, international football games and even had a Summer Olympics in 1968.
The crews also created a postal system, hand making the stamps, for letters home. The Egyotian postal service legitimised the stamps, making worldwide use possible.
This cover's frank says it was mailed on board M/s Agalampus. This was actually a combination of two Blue Star freighters, M/S Agapenor (carrying plastic toys from China destined to be sold in Woolworts) and M/S Melampus. One stamp is blank apart from the anchor logo while the other states Air Post 1/3d.