The small overhead hatches were made by Bowmar in the 1980's era boats. Not sure if they're still in business, as their hatches did not hold up all that well & would develop leaks. The original fiberglass model was designed & made by Catalina of course. The later model C 30's have a more hexagonal designed hatch that I believe was made by Lewmar, & is pretty good quality, but all plexiglass will eventually succumb to stress cracks. The Lewmar hatch will not fit our older boats, as Catalina had to change the shape of the hatch fiberglass flange lip to account for the different shape of the new hatch. This Catalina Owners website has a link on the right side of this web page selling a 1 piece replacement type. It's not cheap, but what large hatch is? I wish they had a larger pic that showed the hatch from multiple angles to access how it looks, but I'm sure it would update the boat a lot. It's also nice to shop from the people who actually sponsor this website, that we are all indebted to for hosting a forum for such great info & camaraderie. Cheers.