Screw seat pedestal to plywood deck?

[jeffconnell12]

Hi guys,

I have an oldie starcraft holiday 18 (aluminum - no fiberglass) that i am removing the sleeper seats on and installing 2 folding seats with 13" pedestals.

Here is my situation.. the boat is not perfect.. the carpet is wrecked and i do not have access to the underside of the plywood deck.

I can cut out a hand sized hole and access under the plywood to set some T nuts.. or i can use some lag/oversized screws and mount the seat pedestal over the carpet and onto the deck.

Is it a horrible idea to screw the seat to the deck? I would love to avoid cutting out the hole and attempting to reseal it with something that doesn't get in the way of the pedestal base.

I do not have a proper space to work on the boat (but do have the tools and ability).. so would love a simpler solution to mounting these seats.

Let me hear your thoughts!

 

[ahicks]

Unless the ply is in pretty good shape (?) there's a good chance those t-nuts will pull right through the ply. Without knowing exactly where the structure is located below the ply, you could run into trouble cutting an access hole too.

What I've seen done, for an install that might be a bit stronger, is installing a 24" square (minimum) reinforcement on top of the original deck, with a row of screws around the outside of that, in addition to the lag bolts or whatever you want to use for the bases.

 

[jeffconnell12]

Okay - I am thinking i will install the pedestal to a base piece of wood using bolts and t nuts then screw the base piece onto the deck (with maybe 3 rows of 4 screws).

 

[Lowlysubaruguy]

I should take a picture of this but I have done this for handicapped hand rails and boat seats for many years. I bore a hole thats as large as possible but still be covered by what ever piece I’m installing. I make a piece of 3/16” to 1/4” aluminum inn a crescent shape that’s I curl into that hole I start with a mod up out of cardboard so i can figure out how large a piece I can work into that hole. I’m usually able to make that cover 75% of the area so its almost a full curl I pre drill it and either tap it for machine screws or make sure the holes will fit the larges SS wood scree to fit the main piece. I route a piece of mechanics wire through one of the middle holes of the plate and then pull that up through the corresponding hole in the floor and work piece its not super easy but Ive had very good luck on rotting floors here and the handrails are sold as all get out in just Sheetrock. Another option is to work that piece in place and glue it in with silicone then carefully drill one hole through it after its cured get that one pulled up tight then drill the rest this way will not require aligning all of the holes . But you do have to wait for it to cure.

 

[TyeeMan]

My current Lund Tyee (and an older one I rebuilt) has an 1/8"thick by I think 12" or 16" square piece of aluminum under the floor boards where the pedestals mount. Use stainless sheet metal screws to screw through floor board and aluminum plate. If you add a base piece of wood I would use marine grade plywood and glue and screw it to the existing floor.