It’s called The Ark by Patrick S Tomlinson. I found out about it through KF where he has his own thread. He is a bit of a.. well, they make quite a bit of sport of him over there. Anyway, the book was pretty good, obivously, because I was able and interested in finishing it. I ordered the other two books in the series, but I fear that they won’t be as good as the first. They seldom are, except in the case of Piers Anthony and Tolkien of course.