Brian,
Kingfisher I: FN680/FN749 (US Navy OS2U-3 BuNo 09513/09582).
Something about the Surcouf here:
http://anciens-cols-bleus.net/les-cl...couf-t8139.htm
incl. pics and drawings of MB-411.
Among the submarine's complement on the day it was lost I couldn't find a name whose trade had something to do with flying...
I suspect the MB-411s were left in France when the Surcouf made it to England in May 1940.
Given the time it would have taken to (dis)assemble the seaplane, its capability probably would have been quite restricted during the war.
Regards,
Leendert