A very exciting story indeed.

This is likely not the very first attempt at it, but seems to be the
first well documented case. I have heard of a tale of a British
expedition to Jugoslavia in the 1950s where they were shown a locally
crafted sea-glider.
maybe someone with contacts there would be able to research the story.

Greece has many fjord-type coastal regions and ridge-lines, complex
sea-breeze effects, wave systems over the sea, a long and hot summer
and having known one of the constructors I can well understand the
drive for the project. I often fantasize about the possibility of
repeating the feat, utilizing modern materials or as a modification
with inflatable or semi-rigid keels and buoys.
There is one serious concern though. When the sea-side ridges are
working well
enough to make a long flight exciting, the sea is likely to be
somewhat rough.....
It would be fantastic as a pleasure-ride ship though.



There has been an article in the British S&G about this in the 1980s.


http://www.cromemco.gr/gliding/English/index.htm
is a kind of portal into greek soaring