The others were named Ra1 and Ra2 if im not wrong, the ones that crossed the Atlantic. Its been 4-5 years since I visited the museum, but I remember it was very interesting (I think it is Kontiki they have on display there). Ra1 sunk a few miles from the Brazilian coast, which is why Ra2 was launched (even though most people agreed that Thor had made his point and that the Atlantic could be crossed in a Reed Raft).