Dead Boat Batteries

I live inland, my boat is 6 hours away, on the hard now. 85 Pearson 34 with minimal (by today's standards)electrical requirements. Boatyard says batteries are toast.
#1 Starter - Diehard #27582 - Group 29hm 675 CCA
#2 House - RAE #E-5 Group 27m, 27m-13, 120AH, 220 min

New to previous owner Spring 2004. Stored indoors & maintained by yard where I bought the boat over winter 04-05. Spring 05, they said the RAE was toast & got me a new one on warranty. They worked fine all summer. Watched them closely all summer on the battery monitor. I probably ran the RAE down a little too far once, maybe twice, but for the most part good voltage etc. and charged back up fine. Any idea whassup?