Replacing the floor in a CVX-20 Jet
I bought my CVX-20 Jet in 1999....Immediately took it up to Trinity lake where my family camped every year fro two weeks when I was young....The next year I took my Father out for his 72nd birthday and tried to get him up on his old ski....Sadly, the beach we used to go to back in the 70s was silted up so he couldn't pull off his Step-start.
When I got home I started cleaning the boat, and as I vacuumed the carpet I stepped back to the rear of the floor and it collapsed! I would find out later that the Engine mount cut-outs had a defect that allowed water from Ski lines and anchor lines in those storage areas along-side the engine compartment to leak under the floor.
I checked and the bow area floor was solid, and also the small amount of floor on either side of the engine compartment. It was only the section from the kick-panel back to the beginning of the engine compartment/bilge. I stripped out the interior, pulling the seats, side panels and carpet. The seats were bolted into T-nuts and three of them started spinning....Just pried the seat up then.
Before cutting out the bad floor, I made supports to go between the trailer and the bottom of the hull on each outer side...I even used some old carpet between the supports and the hull. I then put jack stands under the trailer between the hitch and the wheels to help eliminate any sagging while the floor was out.
Then I used a circular saw set at 1/2" depth and started cutting the floor out, which is 1/2" plywood....I would cut a small section and then flex it up and down until it broke loose from the stringers. Watch out for where the floor blends into the hull at the outer edges- If you are not careful you can cut into the fiberglass of the actual hull structure....
After the floor was out I checked the stringers by tapping on them and even drilling into them- Found one bad spot just in front of the bilge and injected some Wood rot hardener into that section.
I sanded the tops of the stringers to get them relatively flat....Then, reasoning that a 23 year old hull might be a little...decrepit, I decided to reinforce the hull. I used some "Baltec" (Now called Coremat) cloth which has micro balloons so is light but really adds thickness, and then some Knytex, which is three different layers of FG cloth woven together....Doing this part was kind of fun; You wet the surface with the catalyzed resin which then drys STICKY (Like a sticky note) and then you take your cloth and...stick it on. After that, you wet the cloth with resin, then stick the next layer of cloth on; You may need to hit the first layer of cloth twice or so to get a good sticky surface for the next layer. The last layer of resin should have some surfacing agent added...basically a wax that floats to the top and then causes the resin to dry hard-non-sticky (And water impervious)
I used the Baltec/Coremat in the valleys between the three stringers, but the Knytex I wrapped all the way across over all three stringers...Note; I did not wet the Knytex on top of the stringers, waiting to do that when the plywood floor was being installed.
I made doublers out of plywood to join the new floor piece to the old floor front and rear, soaking these pieces with resin and installing T-nuts.
I found that Glastron had used 4x8 plywood sheets for the floor, but since the floor needs to be 51 inches wide, they used two sheets....I would need to do the same since the replaced section would be 7 feet long....So I came up with a better idea....
When I pulled the old floor out I had seen that the outer edges had a support strip- just a strip of wood that really didn't even touch the inside of the outer strake where the floor ended...I had planned on carefully measuring a proper piece- but now I decided to go a step further; I bought a couple of 2 x 3s and cut a notch in each for the outer floor edges, while shaping the opposite corner to fit the inside of that outer strake; it has to have the corner rounded lengthwise, and the front end has to taper both in and up to fit the strake...I also angled the lower-inside edges to make a smooth transition for some FG tape to glue on. These mini-stringers then made up the 3 inches(I.5" per side) I needed for the 51 inch wide floor opening. Doing this allowed me to only use ONE 4 x 8 sheet of marine plywood for my replacement floor.
I cut in Clean-out holes under the rear seat, with plastic deck plates to keep water out but allow Checking for water and removal.
Also, I installed T-nuts for mounting the seats- The driver's seat I mounted on a slider to allow adjustment for driver size (But eliminating swivel) and the passenger seat I mounted on a lazy-susan. Both of these seats mounted on top of pressure-treated wood platforms (Note; I recommend using the stock mount for the passenger seat-The lazy-susan doesn't work that well).....All wood was coated with resin.
Once everything was properly fitted, I bonded the two mini-stringers into the outer strakes with epoxy, then taped the inner edges with FG tape and resin.....I had found that the actual floor was curved, with the center slightly lower than the outer edges (Probably for water drainage) So I had my Father come down and stand on the floor when I installed it. I coated the tops of the stringers with resin, and coated the notches in the mini stringers with resin and then a strip of FG tape that I wetted for the floor to stick to. Placed the floor in and had my Dad stand on it while I installed screws in the doublers front and rear, and then wood screws in those outer mini-stringers (Not TOO long!!!!) and longer screws down into the stringers. After my Father climbed out the floor stayed down in the middle.
I let it dry for two days, then taped the outer edges, and finally coated the whole floor with resin and cloth....
Some would doubt my (Partial) floor replacement, and even some of my non-standard procedures...Well, here it is 2020, and the floor is still rock-solid after 19 years of use- and I have been using the boat every year for 20 + weekend river trips (Each year) plus two weeks up at Trinity lake for Most years (The lake was basically empty from 2013 to 2016 because of extreme drought)
Along with all of this, I also moved the kick-panel forward for more leg room- and made it removable.....And the carpet is now held down with the back seat, kick-panel and side pockets (So it is removable for cleaning) I also installed a Mini-Rail engine mount system which protects the stringers from twisting force from the engine's weight.
After all of this, I found water STILL getting in under the floor! I tracked that down to the engine mount cut-outs....They had boxed in the cut-outs for the thru-bolts, but had left small gaps at the bottom....I have another thread that details my filling these holes in...Critically, I filled those holes in back in 2001-2...And since then have not had any water under the floor- even placed a paper towel in there to see if water would soak it at any point; Absolutely nothing!
Fixing the leaky engine mount holes thread; viewtopic.php?f=22&t=11656
Removable kick-panel thread; viewtopic.php?f=20&t=11679