installing seat base on G3 1548 VBW

[riverbud55]

Looking to Install some seat bases to the rear bench seat of a G3 vbw,,wondering what they have for backing, if any? Trying to figure out what it is so I can have what I need for the best way of attaching the bases,,, going with 3,,,, 1 center, 1 left and right for driving with the tiller,,,,the front was real straight forward, had the backing in place with the pre punched/drilled 2-1/4'' hole in the backing for the seat base also giving its location,, all I had to do was get the hole saw out drill it out from under the deck using the existing hole for locating it and drill some 1/4'' holes for some 1/4'' ss flathead screws......kinda of wonder if it has some formed double plates as the front did or maybe plywood as does the bow deck has for mounting a trolling motor ,,,,,,,,,,know factory puts a center one in the FL models

 

[MrSimon]

Boats like that very rarely have plywood backing under the rear bench. Its likely that there is just foam underneath the aluminum.

Its going to be very difficult, almost impossible, to gain access to the underside of your rear bench, especially considering there is a huge block of foam in there.

Fortunately, that aluminum is probably pretty thick and could support a seat base without additional bracing underneath. Attaching it will be the problem. I've had luck with actually welding a base down, or using large heavy duty pop rivets.

 

[riverbud55]

Thanks for the reply,,,,was kinda thinking the same thing,,,,,,was thinking maybe of getting some 1/4'' rivnuts for the outer 2 ,,,mite drill and countersink some extra hold down ,,, not a lot of stress on the outer 2 as compared with what the center one will have to deal with, plan on putting like maybe 20'' extension seat pole,,,, own a sheetmetal/weld shop so beefing it up wont be a big problem,,,,, at this point thinking of adding a aluminum 3/16'' formed up doubler plate say 20'' wide X the width of the seat and then bend over the ends 2 or 3 inches with holes so they go into the side also,,, think the rivnuts maybe the way to go on that also,,,, not to crazy about welding something up that has foam behind it

 

[MrSimon]

Making a cap of sorts for the bench is a really good idea! That's awesome you have access to fabrication tools.

Will you put anything between the seat and the new cap? If water gets in there, it could cause corrosion over time.

EDIT: Just a thought here. Since you have access to a full fab shop, would you ever consider cutting off the top of the bench, removing all the foam, and fabbing up a reinforced hinged top? You'd end up with a huge storage box with a lid strong enough to easily hold three seat bases. I realize some folks won't remove foam, and some do - you'd have to make your own decision on that one. Just thinking out loud.

 

[juggernot]

If your not planning on using a pedestal on the rear bench I think adhesive and drilling/screwing the bases down would be fine. I've screwed alot of stuff to my G3 after drilling pilot holes and have yet to pull a screw. I have used the smallest SS screws I thought would work so if they pulled out I could go up a size and re-fasten them. A reinforcing plate screwed to the bench to spread the load/ twist of a pedestal and screws through it and the seat base would probably be plenty strong.

 

[riverbud55]

Well ended up bending up a 3/16 aluminum plate and screwed it down,,,,,came out nice and sturdy even with a 15'' pedestal installed on the center base ,,, beefed up the center mounting by with a 1/4'' doubling plate all holes for the bases were drilled and tapped for 5/16'' ss bolts,,,,

1st thing I did was use a 2-1/4'' hole saw to drill out the center hole dead center of the bench seat,,,,,was hoping to find some kind of backing but found nothing,,, so went ahead and bent up the 3/16 plate with pre punched 2-1/4 holes for the bases,,,, screwed the plate down with #12 self drilling ss flat head screws,,,,then took the hole saw and drilled the boats bench seat for the outer 2 bases ,,,, low and be hold if I didn't find 5/8'' treated plywood for backing on the 2 outer holes,,, also pulled up wood shaving when I was drilling for the tapped holes for the center base,,,, so guessing it was built with the idea of having a center base but who frign knows

now time to find some seats I like,,,, borrowed my bow seat out of my big boat for the time being

need to find some paint that matches the g3 paint,,,, been panting every thing that I'm building for the boat with some camo paint from pep boys