Prinsu Rack flush mounting seat design

ABSTRACT
Upon sitting on my prinsu rack I decided I needed to build a flush mounting bench to distribute the weight of my ass, provide comfort for my ass, and allow for a companion to join me in looking out upon what ever gorgeous view I happen to come across. Thus my flush mounting bench design began last night.

Background
I was driving along the blue ridge park way and came across an outlook such as this one. So, to increase my visibility I sat on my prinsu rack with my feet dangling by the passenger side door. It was a righteous time but it hurt my butt, so I decided that with all the modern technology we have I should have the luxury of sitting in comfort on the roof of my 2018 Tacoma. So, I did a real vague google and decided that noone sold what I wanted and it was up to me to design and at some later date fabricate a flush mounting seating apparatus that would attach to my prinsu rack.

Design
Upon arriving home I was trying to decide the overall layout of the bench seat. I realized my roof rack platform I wanted to work with was 55 inches long (front to back) and 47 inches wide (side to side). And thus the basic design process of trial and error and head banging began until I was convinced by a friend that the seat needed to be bi directional so I could look out the passenger side and driver side. And thus the Flush Mounting Prinsu Roof Rack Bidirectional Bench Seat was born.

The hinge system I modeled was based off of this bad its a bench seat hinge boy https://www.hardwaresource.com/bench-seat-hinge.html. I really did not wanna deal with springs so I opted out of them. To keep the bench seat flush I decided to have the outer 2 panels mounted with no intention of moving and the center guy would be held down by 8 pins (subject to change) kinda like hood pins to allow for quick release from one side or another to allow the seat to raise in either direction. Since my research indicates the average human exerts about 60lbs of force with there back while sitting (https://www.agriculture.purdue.edu/fnr/faculty/eckelman/pdf/pdm3scan.pdf) and for a man of my size 140 lbs if they put there back into while sitting, I realized using a spring to keep the seat upright was rather impractical as well so to keep the seat upright as such I was intending to use a tether that would mount to the center guy to the edge of the seat platform. I would hook the tether after scooting onto the seat tho. I was debating using the hinge system off of a beach chair, but i believe using these hinges would allow for a smoother motion, assuming there hefty enough for the application. I have yet to look into the logistics of mounting this system to the roof rack. I know i can get sliding bolts for the 80/20 from their website so It should just be a matter of brute forcing it all into position and drilling the corresponding holes.
The wood would be 3/4's seats would be 14 inches by 55 while the center guy would be 19 inches by 55 inches plus or minus a little once tolerances are considered

Questions comments or concerns? I intend on building this... but I am trying to move across the country in the next few weeks pending my start date so it'll be put on hold for a little bit.

 

I admire your engineering design/planning and skills. If you want to save some money and try another method, you might like what I did to my 4Runner. Like you, I would use my rack to sit on, then started to sleep up there. Needed something light and cheap, and did not want wood due to rotting concerns and sun exposure. So I installed chicken coop flooring. It's not aluminum or steel, but it was effective. It's a tough plastic like material. Your plans are great and it would work for sure. Just wanted to give you and TW another idea. Here's a link and some pics of it on my 4R from a few years ago:

https://www.qcsupply.com/93334-dura..._lqYG6W0uKqaR5SivChYuN3QvJ6ZMBrhoCje4QAvD_BwE

 

I do like the use of the poultry floor, I just used wood in my model cause I knew it was easy to aquire and work with. Im torn between going with a something like what i modeled or just placing down a sheet of something light weight that wont cause to much disturbance while driving. I think a piece of nice plywood would be cheaper to cover the entire roof rack, I built a bumper for my land cruiser a while back and used laminated pine to top the bumper to give me a platform to stand on while working on the engine (fantastic for when the head gasket blew up). Something about the way wood and metal look together makes me happy. I could not find any photos of the bumper after I mounted it on my land cruiser. If I still had it I would of uploaded a picture of it in person.