The Upholstery Forum

So quick question for those with experience in recovering pontoon boat seats. My question is how did the factory attach the cushion circled in blue. These are all plastic bases. The trim piece (cushion) was screwed into the base from the padded side of the cushion as in under the foam and vynil that was attached via Staples to the back of the wood and curved plastic. There in my mind is no way that they could have attached the piece with the foam and covering on and no way for them to have secured it and then secured the foam and vynil. Is it magic?

I've only done traditional boat seats, but . . . .

If there are no visible fasteners from the back, then try looking into the space between the top cushion and the trim for signs of a metal 'strap' which will have screws in it. (Red lines)
Boat cushions are usually held in with 'Z' brackets and/or 'hold-down' straps. Often the hardware/fastener is hidden between cushions/trim.

If that does not pan out, and if the back is upholstered (probably) there may also be fasteners from the back that were installed as an intermediate step before the fabric was secured at the bottom of the back. . . . but maybe you looked there first

Agree with @TedP
that it could certainly have been attached from the back before securing the vinyl. Also seen them use those little plastic door panel trim clips or velcro

Its pretty common for pontoon boats to have screws driven straight through the vinyl at an angle hidden between where the two parts meet. Crazy in my opinion but its common. Spread the two parts apart and see if you find any holes in the vinyl. If you do thats where the screws are hiding.

Thanks for all the input. It still remains a mystery. I'm thinking Jon's suggestion might be Whats going on however I haven't been able to find any access slits. They will be re engineered so to speak when they go back on.

Triton boat seats also put a screw right through the material. This hurts to do on a brand new upholstery job

I just did curved boat cushion like the ones you are showing. Had to take it apart to see how it was constructed. The cushion was a long curved piece, shaped like a big candy cane. The entire length of the cushion was sectioned off as it turned the curved and there were tabs/straps sewn into the seams (not seen from face of the cushion) and those tabs were pulled thru between the sections and stapled to a back piece which was made out of a 1/2" styrene board. Staples did not go through to the other side, so they were not seen from the back. stapling and assembly was done section by section around the curve. Looks like that is what you might have there? Just guessing.

Interesting how many different ways thisncan be done. The only way my cushions could have been mounted from factory was the slit in the vinyl and screw from the front. I never did find the slits though. I changed them over to a tnut and secured them with nuts and washers from the back.

Glad to hear you got it sorted!