It seems it was not just the Flaminia engine that was considered for powerboating, I was recently reading a book I have about the 1954 Formula 1 season which was the year Lancia entered F1. In a quest to learn more I found this article
http://www.classicdriver.com/uk/magazine/3200.asp?id=12842 which mentions that a Lancia racing engine had been sent for fitting in to a power boat!!
Rhys