Desculpe, acho que encontrei minha própria resposta depois de pesquisar outras combinações de termos. O Dançarino da Atlântida , por Poul Anderson, 1971.
An experiment in the future gone awry...and Duncan Reid, American architect of the 20th century, came out of unconciousness to find himself hopelessly marooned in the far distant past.
Bound to him were three of the strangest humans he had ever encountered... a medieval Russian, and a fourth-century Hun, and a sacred priestess who worshiped him as a god. And all shared the same fate--pulled through a hole in time to a present which was ancient history. Together the quartet formed a strange alliance which none dared break. For not only were their own futures at stake... but the very future of the world they had found....
Eu fiz um monte de googling antes, mas não achei até agora.
Menção do RAM do Google Livros:
Down the center ran a raised and bulwarked deck, beneath which passed thwarts for the rowers. The ram was a beak projecting at the waterline, bronze-sheathed, backed by heavy timbers.