Kevin: I've seen the batteries on the screwed down tray before the cockpit and/or Cabin liners are installed. There are several screws as I recall and once the liners are installed the access to the screws becomes quite a challenge.
In addition the batteries are secured to the tray with nylon straps.
Unless I'm mistaken, accessing all the screws is a futile task.
Shouldn't a better means for sliding out the almost hidden batteries be designed ?
The design goal is obviously one that secures the batteries from moving about with the various boat's motion.
Here's a picture of the 4 batteries installed on my 2018 R27/OB.
https://www.icloud.com/sharedalbum/#B1AG0ehgLGfnZiA
The batteries are in a black tray that the batteries are strapped to. The white starboard base board the batteries and their black tray sits on is I believe screwed down (this maybe incorrect) with one of more of the screws used to secure the black tray to the starboard base. Unless it's just the aft screws holding the white starboard base plate to the underlying stringer it would be nigh impossible to unscrew the other screws holding the white starboard base to the underlying stringer as the batteries are eventually hidden. Even if the batteries can somehow be removed there has to be enough cable slack to allow the batteries to be slid out and exposed.
Now, if the starboard base board isn't screwed down to the underlying stringer then with some effort I'm guessing the whole tray of batteries can be slid out to be exposed so long as there's enough cable slack.
Correct me if I'm wrong about any of this. Thanks.