Ski nautique to xti interior conversion

This is going to be a two parter, this post is part one and will focus on the layout and upholstery and part two will cover the semi-auto/hidden ballast for direct drives.

The ultimate goal for this project was to take the old competition skier to something a bit more modern as far as storage and useability goes, more like a modern wake boat. The wake produced by the SN2001 line speaks for itself.

The original post made in the in progress project section can be located here 

Step one on my project came during the tear down for my stringer/floor job a couple springs ago. After thinking on ways (and doing a sub-par conversion) to accomplish the goal I had the interior apart, at that time I took tons of measurements and even outlined it all out on the floor so I could lay my eyes on it in that boat. Then transferred all that to graph paper, and saved it until I got started.

The next step was to get started on the seat bases and the frame for the motor box. I used wood coated in epoxy resin, and eventually covered in carpet for this. Most everything ended up being scrap I had from the dolly I used for the stringer and left over resin. Seat bases are 2x6 motor box is 2x4. 

I started with the motor box and built the four main supporting posts up to the same height. So the sun pad would sit flat. The gunwales on my ride gradually slant toward the transom so I had to build from the floor up to get a level surface. Once built, and test fitted, I moved to the seat bases. I decided to go with corners over curves like the Malibu's for the ease of building. 

Once the frames we're built, I had to take some material off the flame arrestor. It wasn't much, roughly an inch or so, you can order them, but I figured I'd try and mod the existing one. After the 34 years of use a slight pry on the top surface cover revealed what was left of some sort of adhesive, I decided to cut the excess material out and epoxy it all back together. It's working great. 

While mocking up the seat bases, I also cut my cushion backing boards. I used outdoor playwood, 3/4" was used for everything that will carry body weight and 1/2" for all the seat backs and misc trim. Again it was coated on all sides with the epoxy resin.   I waited to coat though until I thought I was sure my pieces would fit correctly. My first mock up, had to be re worked because I did not account for the padding to be added to either the seat backs or cushions. 

Next step was upholstery, I ordered a total of 13 yards for this project, 12 of the main color and one of the accent. This boat is small so I'd imagine most folks would need a good bit more vinyl then me. V-92 polyester three and a #18 needle was used in my very old singer 15-91 sewing machine that I had to rewire prior to use. I picked foam on eBay, used 3" for the seat bottoms and 2" for the backs and sun pad. This had a 55lbs force rating, I would not recommend going any lighter on foam this thin that will carry body weight. 1/2" foam 45lbs was used for the other panels and around the speakers. I also used silk plastic as a moisture barrier between the vinyl and foam and the basting tape (double sided tape for upholster) both from sailrite. 

Sailrite has a great diy upholstery video selection on YouTube, that really got me going in the right direction. They include part numbers and info on everything the use in the videos which makes finding supplies simple. 

When it came time to see, I wanted to do what I thought was the most simple pieces first. A solid colored seat cushion for instance. I started by taking the wood base. Flip it face down and trace out on the bottom of the vinyl. Add 1/2" all the way around. Then I cut the side pieces. I need 1/2" plus 3" for foam plus 3/4 for the base plus about 2 for Staples. Maybe 6 to 6-1/2" wide material the length plus some extra of the perimeter of the piece. I just rough measured everything. 

The foam was cut with an electric turkey knife at roughly the size of the base plus half an inch all the way around. I did not want to see the edge of the bases through the vinyl so the excess foam helped in addition to routing the edges top and bottom.

Adding the accent color was a bit more difficult, especially since it was from scratch, all my accent colors were straight lines so I imagine that was better then doing curves on my first upholstery attempt. The key was picturing the finished product, adding that half inch for my seams and not rushing. I drew the pattern on the surface of the base, then a was able to trace it and stop at the seams for each individual piece of material. On the seats I had patterns for, I used the old vinyl as a template. 

Of course there is a learning curve and it shed up on my top stitching, also in the pic below you can see wrinkles in the cushions. Once I added foam and vinyl, the gap between the cushions I initially left was too small. I picked the Staples out re cut, re epoxied trimmed the foam, trimmed and re stitched the vinyl and stapled again to get it tight. I can't remember exactly, but it needed closer to 1/2" between the bases to ft snug. 

Below are the finished pics. 

I didn't mention it before but the bottom side and insides of the cushions and compartment pieces are covered with carpet and I ordered the cushion stops from nautiqueparts to keep the loose seat cushions in place. Stainless cup holders can be had for cheap on Amazon, I added 7 in the new parts of the project. I got the piano hinges on eBay. Stainless and/or aluminum for cheap. The pad above the speakers on the transom attach with Beau clips (I think) from sailrite. They press in and pull out by hand. Great for panels with little to no access for carriage bolts. 

Side note: the vinyl I also scored on eBay for pretty cheap, quality may end up showing that, I didn't want to buy high end stuff and ruin it trying to sew. I can't speak for other brands, but this Bron gets really hot in the sun. 

Overall we are really happy with the useability of the boat now. Feels a lot roomier and has tons (compared to before) of storage.