Yo Chip

Very nice looking rig. I am not seeing enough string from the bows/Stern to the bumper bars/tow points for my liking though.

You can go a fair way with the kayaks moving about a bit as pictured and reported, but when the babies go, they go fast and far. I have found that tie-ing the bow to both corners at the front and the stern just to the tow bar settles the shifting from side to side down to next to nothing in even the strongest gusts.

I concede that you probably can get away without lashing for and aft if you have a van where the racks are far apart and you don't have too much overhang.

What seems to happen with a catastrophic failure is that the wind picks up the bow and lifts it. Then the leverage kicks in and wrenches your rack clamps clean off the gutters and denting the back of your roof as your kayak takes off still firmly attached to what is left of your racks. With the bow tied down the roof rack becomes a cradle (and only has to function as such) and the forces at the end are secured and kept in check by the ropes.

And I laughed a few years back when a guy told me he stomped on the brakes and his entire roofrack with kayaks scritched across his bonnet and landed on the road in front of him .... Then there was the time when I saw a guy with a load of gibralta board (sort of gypsum plywood) stop suddenly and the roof rack with several sheets of the stuff smacked onto the road infront of him leaving the coolest square chalk mark .

It does happen

Cheers Pete