transporting tandem using j style rack

I did a quick search on this forum to see if this had been discussed and I didnt come up with anything. So heres my dilema I have a mini van with the factory roof rack and I use a J style rack for my kayak but I want to put my old town 14 ft tandem up there and travel about 180 miles on the turnpike. I believe it weighs about 68 lbs. I was just wondering if anyone else has used the J style rack with a tandem and if they had any problems doing so. I guess Im most worried about traveling 65 mph with it. I have it also strapped down in the front of the van and the back. Any suggestions/concerns would be greatly appreciated since Im about to leave on our trip tomorrow afternoon with 2 german shepherds and a puppy. Thanks in advance. Have a great day.

A 14’ boat should not be a problem
just make sure you use bow & stern tiedowns, and that they aren’t pulling the boat in the same direction (usually forward).

Bow tiedowns usually go forward from the bow to the bumper, so make sure your stern tiedown drops straight down to your bumper rather than angling forward from the very end of the stern.

Otherwise both tiedowns will pull the boat forward, and with enough bumps it WILL shift forward, with foreseeable results (“Minivan runs over own kayak, video at 11”)