Need help putting swivel seats in jon boat

[mugsync]

I need to attach plywood to the aluminum bench seats in my 14ft jon boat so I can mount swivel seats. What is the best way to secure this since I am not able to get under the alumimum beach to use a standard nut/bolt?

 

[tashasdaddy]

Re: Need help putting swivel seats in jon boat

toggles, http://www.iboats.com/Garelick_Stai...928731187--**********.255571232--view_id.2616

 

[mugsync]

Re: Need help putting swivel seats in jon boat

I saw the pic of the Garelick Stainless Steel Toggle Bolt Anchors but would it not have the metal sticking out of the top?
Isn't there a lag bolt or some type of screw that would work that I could pick up from Lowes?