battery placement

My newly acquired Hunter 260 has a battery selector on the false bulkhead at the back of the aft bunk. Circuit #1 goes to the house battery sitting just beside the selector, no problem there. Circuit #2 goes to a cranking battery mounted in the gas lazarette, beside the gas tank. I see two...

When I purchased my 1979 Hunter 30, and the batteries were in the lazarette and not held down to anything. The fuel tank was on a wooden shelf above and aft of the prop shaft seal. There are some nubs on the bottom of the cockpit floor just forward of the pedestal that look like something...