I was going to suggest using Google—then I found out a 2013 Subaru Outback search isn't too easy...
When you've lifted a Sunfish chest-high, it suddenly becomes very heavy... ...also, check out the weight limit for the Subaru roof.
Among others that are smaller, there's the reasonably-priced "MegaWarrior" by Yakima that could be modified to hold a Sunfish: http://tinyurl.com/aggagal
Here's a reply to my question about a rack with three kayaks on it:
The rack is a Yakima, it did bring the Sunfish home on it with no problems, its a good rack and I've had it on my van for a number of years with no issues. It has locks on the towers so no one can steal it.
I would configure the roof rack so that the bars go across the car. Then I would get some polyethylene foam tubing (pool noodles) and put them around the bars. (If they need to be cut to go around the bars, then secure them by wrapping the tubes with duct tape or rope every 6 to 12 inches. This would pad the boat and allow rolling & sliding it onto the roof. Then I'd use two ratchet straps over the middle, padding the straps with more tubing if needed; plus cam straps from bow to under the front bumper where there might be a hook, and strap the stern to under the rear bumper. (You could use rope for the front and back, but I said cam straps because I would tend to over-tighten ratchet straps and fold the Sunfish over the car.)