Agree about Rodgers, and I also highly recommend "Gunpowder & Galleys". Guilmartin also has some articles on the topic published on from his web site – look at the bottom of that page under "Articles". Some of these are actually elaborations of what he says in "Gunpowder & Galleys".
There's a wee bit of information in the Osprey book "Renaissance War Galley", but only just enough to whet the appetite. It's sort of like Cliff Notes – if you already know the subject, you can get information out of it, but otherwise it's hard to tell what's important.
The Time Life book "The Venetians" (from the delightful old book series "The Seafarers") also covers the topic, but like the Osprey, there isn't enough in there to write a whole wargame.
Between the three of the above, you can start to piece together the weaponry, tactics, measurements, national differences, etc.
Some sort of anti-recommendations:
Guilmartin wrote a second book called "Galleys and Galleons" which is a much lighter treatment of the subject. Not all that great for wargaming purposes, but again it does elaborate just a bit on the subject, so worth reading if it's free/cheap.
I found "The Galleys at Lepanto" by Jack Beeching to have some excellent social and political background for the War of Cyprus and the battle of Lepanto, but it has almost zero material/technical information. The main thing that stuck with me were the comments about the smell of galleys (servile rowing gangs chained to the oars had to answer nature's call where they sat).
This essay about signals on Maltese galleys by John Muscat has some interesting information, though any insights about the nature of galley warfare are oblique.
- Ix
