One for the purists here, the detail goes quite deep (right down to individual log entries), but if you're a bit of ship spotter it is a good read.
The Napoleonic era is my favourite period from history so there was added appeal for me; this book tell of the life of the Bellerophon.
The chapter on Trafalgar is quite long, as you'd expect, but even though I've read many books on Nelson/Trafalgar, I've never read from the perspective of an individual ship.
There is also a good portion dedicated to the surrender of Napoleon and the time he spent onboard awaiting his fate. I'd give it an 8 out of 10 for those with specific interest in the period or ships of the line.