Battery recommendation

I just run down to the local SAMS club and buy my batteries.  They are all dated so buy one that is fresh.   Take your tape measure with you and you can measure the available sizes to see if there is a better fit for your boat.   In boats where the battery gets pounded frequently I have found the batteries with less amps live longer.  So instead of buying the 900 AMP battery I will settle for the 650 AMP.  The plates inside are not as big so not so close together, they seem to survive a little longer without shorting out in boat service.

All back together, but still fighting the starting issue? WTF! I was fairly certain that bypassing the relay via the alligator clips, to get the starter going, isolated this issue to that solenoid relay? Hmmm...maybe not....had battery on charger all night, and I do have 12 volts, and everything powers on. I double checked the NSS, and while I do need a new connector, it is snug. Thoughts? Ignition sw at the dash?

New battery is easy and you were asking about size so I assume you figure you need one. Might as well start there. Or a super simple way to prove that out is to jump your current battery to your car and see if that solves it.