I'm with XORT on this, pair down your starting bank with a single battery and increase your house bank to 6- 6 volt T105's. You may want to wait until your current batteries are finished because re-arranging them now will shorten there lives a bit. Some here will tell you that one big bank works fine, but I would only do this IF
you have a pull start generator ready to go.
The banks you have right now is mighty big (and heavy) for a 38 foot boat......unless of course you have the hot tub option with the 1000w stereo!!!