There's also a hard-coded flag in the save game for each country which allows or disallows certain techs even if you've researched them. In the case of Brazil, transports are not allowed.
I've said elsewhere that the first thing I do in any game is save on January 1, 1936, then go into the save game file and change these flags so that any country can have any tech so long as they wish to put the work in. I've not seen any Albanian aircraft carriers or Siamese submarines, so it doesn't seem to hurt.
Cheers,
Paul Drye