You are correct, I’ve tweaked my back and dropped them both haha. I load up a lot of canoes and kayaks at my weekend jobs, and of course usually loading them up when I’m off work too.
I can get the Jackson kayak (somewhere around 90 lbs) onto the rack in the bed of my truck solo but I wouldn’t dare try it on a car/suv alone. I can lean it against the rack and just slide it on
And pictured below are the back tweaking days