I rebedded that front hatch with Bed-It-Butyl on my 310 and also on a friends 309. It worked fine; we just unscrewed the hatch, popped them off, cleaned them off, then used a couple of layers of butyl tape to make sure we have a good seal all the way around and re-installed. They used some cheap butyl tape at the factory and on the 309's it liquefied a little. It has been a few years and has not leaked since. I seem to recall we just tightened them up once and were done.
It is an old thread @JK_Boston_Catalina310 but an interesting fix. Having just installed a Lewmar hatch on my boat last week... I will keep the Butyl idea for possible future leaks. I did take the hinges off and there was the same foam gasket under the hinge on a new hatch.
We used butyl to seal the hatch to the deck. So far after the rain from the weekend storm. No reported leaks.
@SawyerCurt first line "I'm going to share a project I did, because I don't think of myself as the most handy guy". Now hold my good microbrew beer while I undo my rigging, remove my chain plate and redo it better than the factory. Hahahahaha
I could not through bolt in all of the holes. SO I through bolted in 4 of the slots along the hinges and 2 bolts on the opposite side. All others were screwed into the wood deck (plywood in my case). Counter sinked the glass, and put a cone of Butyl on each screw before I screwed it in. I also laid a thick layers of butyl all the way around the flange. So far no leaks reported during the first night of rain.