I have hauled kayaks in my shortbed pick up truck with a old red shirt looped on one of tie downs that ran the back of the kayaks. Do I still haul my kayaks in the bed, no and for two reasons. 1. I bought two new kayaks a 12’ and 13’ that are both 34’ wide and I quickly realized that after decking out the kayaks for fishing they would not fit in the bed with out taking rod holders, fish finder holder and other accessories off the kayak. 2. I picked the new kayaks up prior to picking up my kayak trailer because the trailer was on back order, on the way home with the kayaks extending beyond the bed of the truck with a red flag driving on the interstate I was in an accident. The car in front of me came to an abrupt stop and so did I. The Ford F 150 behind me came to an abrupt stop 2’ from the kayaks, and then a person not paying attention rammed the back of the pick up driving it into my kayaks. Luckily the damage to the kayaks were minimal with just a few scratches because of the slop on the Fords front end. If the truck would have been a Dodge, Chevy or GMC with the square front end the kayaks would have be damaged beyond repair. You can pick up a continental two person kayak for less than $800 and well worth the money.
Having them sticking out the back is an accident waiting to happen. It’s not worth it. You can figure out a way to get them up on something like that ADARAC system. I know you can. I used to load one or two on top of my old Honda Odyssey van in my mid and late 60’s.
Actually, I do carry my boats in the back of my truck and don’t even use bow and stern lines:
(16’ box truck camper conversion with overhead door-- there are eyebolts in the floor and I do strap them down before driving.)
When kayaks were on top of the Yakima racks or the pop up slide in camper I used “Hulirollers” on the rear rack. They needed regular maintenance so they freely rolled. Otherwise the roller would stop and the rack would roll on the bar placing the screws of the wing nuts onto the hull of my boat.
Some of my Sterling friends have a roller rig but it is more technical than my rollers. They work…all the time. Of course those guys are loading 35# boat.
That works but it can make for an awkward lunch stop. And you have to load and unload at every overnight whether there is a paddle or not. However I seriously considered a “toy hauler” trailer. Can work with bicycles too.
I can actually carry one boat on top of the folded down double Murphy bed and still have room to sleep beside it. Hauling the boat(s) out for the night only takes a couple of minutes with that easy access – don’t even need to pull out the ramps since they come out easily to carry at chest level.
But I have several folding kayaks (Feathercraft and Pakboat) so for longer trips they will ride along under the bed frame in their duffel bags. Can’t beat the “toy hauler” for security, anyway. The kayak is 15’ and the canoe is 13’ 8". Could also use the kayak trailer but that plus the 24’ long truck makes for more length than I care to handle!