That boat is exactly like mine except that mine has the sun sport seating (big sun pad over the engine compartment and full width bench seat in front of that).
The hatch is not under the rear seats but runs down the center of the deck in between those back to back seats. You can't see it in the pic because of the carpet. And that thick nice carpet is exactly what causes the rot in these boats. It gets wet and holds moisture against the deck for months. Then there are other poor construction details:
I bet none of the holes for mounting the seats had any sealer in them
The deck was attached to the stringers with a lot of nasty rusty staples each one creating a spot for rot to start. When I fixed mine I did a few things different:
Used a 2 piece rear seat & rear bulkhead to make engine maintenance easier
Sealed every hole for mounting the new deck to the stringers
Sealed every hole for mounting seats
Threw the carpet in the trash and had the new deck 'glassed in non skid gelcoat. Which is effect a fiberglass liner which is how any open boat should be built.
8 years later it's still solid.
In these 2 pix you can see the hatch....
https://www.dropbox.com/s/lfs7ioudwrnkn ... a.jpg?dl=0https://www.dropbox.com/s/ds48pon6ov5tz ... 1.jpg?dl=0Here's what I started with....
https://www.dropbox.com/s/e316zo94sig9y ... r.jpg?dl=0After stringers were repaired, new gas tank mounts built (out of mahogany) and foam installed...
https://www.dropbox.com/s/pes4wf5zt63mx ... n.jpg?dl=0see why you need to be careful with old boats....