Kayak carrier - over the cab on Ram 3500

I’m looking at the Thule Hullavator and the best way to mount it on my Ram 3500. It needs to go over the cab as we pull a fifth wheel trailer. Wondering if anyone has put one on a pickup cab and/or if anyone has had experience with a American Rack - Fifth Wheel Truck Cab Rack using the Hullavator?

Thanks in advance for any helpful feedback.


here is my set up

– Last Updated: Dec-29-13 12:57 PM EST –

I also have a front receiver hitch installed with a "goal post" style extension I got from Northern Tool. I did have to extend the tube on the goal post to make it so the boats ride level.
The rear (bed) rack is removable when the fifth wheel is attached. I built the roof top brackets out of aluminum and they are bolted to the roof using Dzuz fasteners, so they are very strong.

It is a lot easier to load the boats over the cab once we drop the trailer, so that is my primary boat hauling method. We can haul four 16' to 18' boats.