The GEO submersible depicts at the top of the stamp, I could almost find nothing on, was used by Dr Hans Fricke in 1986 for his research on the coelacanth in South African waters.
The team had gained substantial experiences in submersible operation since 1981 by using the manned submersible “GEO” for their research tasks. GEO had a depth rating of 200 m and was built in Switzerland on the basis of ideas of Hans Fricke. A research highlight achieved with GEO was the first in situ observation of the coelacanth Latimeria chalumnae, an ancient fish closely related to those fish-like vertebrates that made the first step on land and thus became the early ancestors of all land-living four-legged animals.
https://www.researchgate.net/publicatio ... sible_JAGO
South Africa 1989 50c sg 680. Scott 765.