I've put screw in, deck plate style hatches/access ports in the aft bulkhead of a couple ch17's. It works great for packing a lunch or jacket, not for big stuff.

The ch-series use wood sheer clamps as a gluing surface for the deck. Boats like the wd's and shearwaters rely on filleted and tabbed joints on the inside, so if the deck hatch is omitted you need an alternate way to get enough glue area in that joint. I'm working on a wd-double now they won't have a forward hatch- I'll glue some thin strips to build up a sheer clamp without altering the pronounced curve at the bow.

     I considered putting these in my Mill Creek 16, but I was concerned that it might be difficult to get the front cover on easily as there is quite a bit of deck over it requiring you to put the cover on one handed or climb into the boat to do it. Ultimately, I went with the screw in hatch covers sold by CLC and they work just fine for me.