Strapping boats together on J carriers?

We have two 12 foot kayaks that ride on the SUV roof in J carriers, with bow and stern lines. They seem secure, but sometimes I have paranoid fears of, say, a carrier or crossbar cracking.

So far we’ve only taken short drives but one day would like to take the yaks on a long road trip. Does anyone ever lash a strap or two around the middle of both boats – basically strapping them to each other – as additional reinforcement besides the carrier straps and bow/stern lines?

Are there reason for or against doing this?


don’t need to
Seems to me tying the two boats together wouldn’t be much help – if on the remote chance a rack component failed it would just put more stress on the other boat and maybe drag the whole load off. But I have driven thousands of miles at highway speeds with two 16 to 18 foot kayaks on Thule j-racks with no disasters. I trust the components very much. I do use extra long Thule straps that I pass around the rack in addition to the j-rack itself and always make sure the bow and stern lines are strong and taut.

Bow and stern lines
are the key. If you have the bow and stern tied the boats will stay on the roof. I tie them snug but not overly tight so as not to deform the boats.