Thanks for the nice remarks.
What thickness of plywood did you use?
The ends are 3/4", and the top and sides are skinned in cheap 5.2mm.
A quick question, I walk on my hatch all the time. Can your "dog house" hatch hold weight too?
Doubtful unless you weight about 25lbs

I also stand on the normal hatch all the time since I lower and cover the mainsail while on the roof. Will have to get used going around it. I am thinking it will be mostly out of the way sailing when shoved forwards to the mast. Its pretty light so may get tossed on the dock with the original hatchboard we keep around for locking it up. It did survive a 5' crash from the cockpit to the concrete drive while I was bringing it down
probably could cover it in fiberglass and finish with a white gel coat. Could be a good "first fiberglass job" if your new to it.
I was tempted to try that. I figure try this first since it was cheap ($12 for the ply and $14 for the paint) and see if I actually like it. If so then try another with fiberglass and incorporate any changes. I picked up a gallon of oil based gloss white exterior paint at the bargain outlet and gave it a coat of that over the weekend. Looks like the paint will be drying awile....but it will be well sealed
It is nice to have greater headroom over main hatch. I prefer to have a cover over the main hatch forward to prevent seas, sand and such to prevent sediments in main hatch that sand the movement of hatch. Like the bigger boats that have the hatch sliding into a cover.
I hear you. If it were more than a marina hood sealed to the roof while longer and beefier would add function. We keep the boat on a flat river at MM0 on the ICW during the winter so its main purpose is to let me stand up straight while having a cup of coffee and putting on my tie in the morning

Once it warms up we will have the kayaks back on the roof and it will have to come off.