I stumbled upon this on e-bay recently and thought it may be useful for those who can take advantage of it. This is a quick bungee system that stows in your rectangular Thule bars. If you don't have rectangular Thule bars, you can probably make something similar if interested.
Description: The package includes 4 hooks, 4 end cap/hook retainers, 4 hook caps, 2 bungees, 4 slides and instructions:
Quality, fit and finish of the fittings looks excellent; likewise, the bungee is heavy duty and made in the USA. The system was manufactured by a small company, Dane Schrader (formerly Schrader Dane) of Vancouver, WA. Though no longer in production, it is still available from the manufacturer and some local retailers.
Operation: I installed this on my front bar and tried it out with the Oasis tandem. I simply pulled out the bungee hooks and hooked them on my conveniently located side grips. Then I tensioned the bungee by pulling it back and pinching it into one of the "V" slots in the end cap. This is an important feature of the system. Here's what it looks like in action:
This shows the hook stowed in its end cap. Note the "V" slots:
Here the hook is pulled away from the end cap:
This shows it gripping a 2x4 using the slide:
This is a close-up look at the slide:
Results: I've used the system to transport the Oasis a couple of times for a few miles. There were no problems although I felt the boat slid around more than I liked. IMO, it is not as secure as ropes or straps for an item this heavy and I'm not comfortable recommending it for kayaks. For smaller items though it's really handy, stows instantly and doesn't get tangled up like my small bungees do.
Limitations: in addition to requiring the rectangular Thule bars, you need at least 3/4 inch bar clearance at the ends so the end caps have enough room to fully seat (they require more space than the factory caps). The instructions don't mention this.
Nevertheless, this clever system appears durable and works quite well. The list price was apparently about $50, but the manufacturer is selling its remaining stock for $20 + shipping according to Barb. At that price, it's an excellent value. It comes with a "lifetime" warranty (or as long as the company is still in business and has spare parts). The company can be contacted at 800-870-2170 (no web site).