You can swap one of those Optimas out.

I am on my EIGHTH season with the original Blue Top Optima I put in my boat in 2007. Still use it as my cranking battery and its going strong. My two trolling motor batteries are Blue Tops I bought in 2008. In my experience in marine batteries that's just frigging unheard of. don't know if its luck or what, but I'm standing by those Optimas. good battrees.

BKB