Anthros,
Do you have any experience with / or knowledge of the Whispbar, extra long ' Through Bar ' ?
I have a new Audi A3 ( no sun roof or longitudinal roof rails ) and I would need feet that clamp onto the door head. Are their clamps as well engineered as their rails? ( solid, well fitted, cushioned etc. ? )
To be clear, I have no direct experience with any of the Whispbar products. For what it's worth, I'm a mechanical engineer, and I've been reasonably impressed: the drag claims are within reason, the prices are high but not outrageous for the benefits, and none of the marketing claims are obviously false.
Also,
Rack Attack sells the Whispbar product, and the various Rack Attack blogs have me convinced that (a) some people at Rack Attack are pretty smart, and (b) Rack Attack wouldn't sell Whispbar products if they were complete crap.
But all of this is circumstantial. Being an engineer, I'm pretty cautious about saying something is "well engineered," especially if I haven't laid hands on it. That said, I wold buy a Whispbar rack sight unseen based on the above evidence. Still, there is a small-but-nonzero chance that I'd regret that purchase.
I need to carry a 4'-0" wide dingy ( boat ) a couple of times a year and the roof of an A3 isn't all that wide.
What kind of dinghy are we talking about? If you have a Laser or Laser II, the gunwale shape should let you secure your boat to any quality rack. (Thule and Yakima both make excellent products, so they keep each other honest. If Whispbar were of lower quality, they would have been driven out of the market a long time ago, IMHO).
I'm not convinced that you need extra-long crossbars--if you lashed nylon straps around the towers and over the hull, it wouldn't matter if the hull extended an inch or four over the edge of the crossbars and towers. As long as you have supports between the rails and the deck, you should be fine.
(Nota bene: Don't take my word for it. Find somebody local who knows both boats and racks).
Cheers,
Jason