Well, when I can't decide whether to mark this mostly SLOW or MEDIUM or FAST paced, that should be a clue that my reactions veered wildly over the course of the book.  By page 100 I was ready to write it off as flat, SLOW and boring:  the time traveler theme that hadsounded so promising was slowed to an enculturation project slog.  

But kept going partly because of reading habits and partly because my wife said it got better.  It did.  Things started to get wonky (a bureaucracy tries to manage time travel?  What could go wrong?) and soon they're deep into puzzling out what smells wrong about this, each in their own worlds and with their own security clearances.  Also falling (lunging?  slipping? groping? negotiating their way?) into lust confused by culture clashes between a Victorian Naval officer and his contemporary "bridge." -- nicely hot I thought -- so it got compelling and MEDIUM paced.  And then the end sped up to the point of fragmented confusion (as a time-travel novel reasonably would).  And we learn how to ride a wave and come up for air. . . several times.   In the end I'm glad I kept going.  Give it a try.