Seat pedestals (any Advice)

[MrG]

When I removed the Side Skirt you can get to the Machine Bolt's that go threw the Base plate & floor, They threw bolt with Nylocks Nuts on the underside. So ya need someone topside to unscrew from up top while you have a wrench on the nuts on the underside. I can see how all the Back & forth from normal use from up top has made the wood floor Not Ideal. Seems kinda comprised. What would be real nice is to Have a Nice base plate for the underside that the machine bolts could screw into ya know Threaded sections. This way it would be supported from the top and the Bottom. I bought a NEW Springfield Marine Seat Base and Pedestal its the 2-7/8th Variety. The Stock Pedestal height was 9inch tall So that's What I ordered. $140 from Amazon. Might try Send cut Send for a custom Underside Plate, And I had my brother 3D print a New plastic insert for the Pedestal after, The new insert and the freshly cut Pedestal Didn't seem to make Much Diff I think lots of the wobble is between the Old Base on the floor & Pedestal its just "Tore up from the floor Up" Looking forward to spring when This project most likely will be complete

 

[FIRE UP]

Well,
Not seeing this situation up close and personal, I can agree with you on a "base plate" below the deck as a strengthener for the underside flooring. If it were me, and we were in that situation, I would do the same but, I'd make that underside base plate considerably larger in diameter and, I'd also make it out of probably 3/8" aluminum (preferably 6061 T-6 because that's considerably stronger and stiffer than your basic bubble gum aluminum 5052 or even 3003. No need for stainless steel in this situation, too heavy, harder to work with and waaaaaay more expensive when some 3/8" aluminum work for this project flawlessly. Heck, I might even almost match that new underside base plate with a larger one UNDER the pedestal but on top of the flooring. You'll get SERIOUSLY stiffer support by doing something like this and it will "sandwich" the flooring/decking and spread the lateral load out in all directions. If you think you might not like the looks of a large additional base plate under the pedestal but on top of the flooring, then just cover it with the same flooring. Good luck on your project and thanks for getting back here with your findings and potential plan(s).
Scott