What kind of dinghy? You might want to check with the folks at boatcoversdirect.com. who has an extremely wide assortment of boat-specific covers. They are in South Carolina. I bought a bimini for my Whaler and have been a happy owner of it, with very heavy use, for over 8 years now. When one of the bows was damaged in accident, their after-the-sale service was excellent.
For my bigger canvas jobs in this area, I used Larry's Canvas in Atlantic Beach; I noticed his shop was still there when I went by Sunday, it's been a couple of years since I last used him for a bunch of upholstery and miscellaneous canvas work on my Hatteras. Super guy.
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"