I understand what your getting at there but I think its all about tongue weight and the maximum amount of weight the vehicle is rated to tow. Boats built today with composites are remarkably light.
The hitch height is too low and the passenger car tires don't have stiff enough sidewalls which is contributing to the swaying.
Towing, and towing safely, are two different things. Just because your car can pull the boat it doesn't mean you should.
I would be more concerned about stopping rather than pulling.
Hope things are well with you and family after the move.
I use to pay a friend $100 buck to haul my boat and trailer, twice a year, lot cheaper that owning and insuring a 3rd vehicle to use 2 times a year. Offering cash instead of asking for a favor keeps seems to work better in my experience. You have options and that is a good thing:roll:Everything about the move has been positive except being so far from the water. That picture was taken at my inlaws in Harpswell. So it was about a 40 mile tow from Portland. We'll need a vehicle more appropriate to haul the boat with. I've towed plenty of center consoles with a car in the past, but this is just at the next level. I would be fine towing it around Harpswell to a boat ramp, but no way am I going on the Interstate again.
Guess I have plenty of time to figure it out over the winter. Hope all is well with you and your family too!