Mine started as a carpet project, I had a soft spot in front of the ski pylon that was going to be addressed as well. I removed the interior and old carpet and noticed the soft spot was much larger then initially thought. After investigating I found it was all rotten. With some urging from a neighbor, I took on the project.
Its not a complicated project, just labor intensive. I bought a black and decker belt sander on amazon, it proved to be the most valuable asset, followed by a 4' and 6' harbor freight level, harbor freight angle grinder, tyvek suits and respirator. Circular saw and recip saw, dremel with cut off wheel.
First part of my project was to remove interior pieces and carpet. I used a battery powered circular saw to cut out the floor. Most of the glass was about 1/4" thick so I set the blade near that level. I left about a 2-4" lip all around the floor as a reference to the height. Once the floor is out you will notice there is much less wood then you think, and it's mostly glass over foam, depending on the route you take on your rebuild, I'd recommend taking pictures and measurements of the supporting areas of wood left over prior to removing. As well as keeping the floor pieces for reference throughout the project. Also note the height of the motor and tranny mounts on the cradle. The motor location is the most important part of the project, floor doesn't matter so much. Remove all the old foam and discard (multiple bags and trash can fulls of wet foam). I did this all outside and it help cutdown on the mess in the garage. Do some research if need be, but the motor, transmission prop shaft should be removed, throttle cable and shifter cable can be flexed out of the way or removed. Steering cable is probably best removed rather then flexed, and I removed my rudder for clearance in the garage.
I took my boat off the trailer for the project, mainly for fitting in my little garage. If you leave it on the trailer, apparently the hull needs extra support, I noticed it seems flimsy when the floor is cut out, I imagine it will sag in the middle with out supporting it.
Now for the really messy part. Stringer removal, the goal here is to save the bottom edge of the old wood to copy for your new stringers. I had 1 out of the 4 that was able to be copied due to the rot. I tried to make a template for the inside and outside of my stringers, ended up way off and had to address it later. To achieve the task of saving the old ones, use an angle grinder with cut off wheel to cut the fillet at the base of the stringer, put the wheel in at a more horizontal angle and you can feel when it's through the glass and into the wood/rot. Once it's cut all around, pry out the stronger and go copy it on your new wood.
The mains are standard 2x 8or10 (can't remember) if you go with the smaller board you can epoxy the gas tanks support spacer on to the rest of the stringer, or use the larger board and have more waste. The secondaries are 1x 6? Stacked together around the exhaust. I mis-measured and didn't realize until completion, had a 1/4 gap about a foot long on either side of the motor box, addressed that later with aluminum angle to hide it. When shaping the stringers keep in mind, if you do a wood floor, and want it the same height as original, subtract that thickness off your new boards.
After cuttings and shaping your new boards coat them with epoxy resin, here is where opinions differ, some say use the penetrating epoxy, according to the west brand epoxy resin, it does the trick alone, I followed that route with the recommended number of coats on their website.
Next we bed in the now coated new boards, I used west microfibers to thicken up the epoxy (called peanut butter due to consistency). Make sure you keep adding it until it's PB consistency or it will ooze out and make a mess. Use the same mix to fillet the corners.
As as far as locating the stringer, a groove was left by the old ones, I also used scrap wood as spacers and clamped it in between the new board and old stringer ( I placed one new stringer at a time, that way I could reference the old ones). Remember that as you add layers of glass the thickness will change making the distances a little different.
So my heights were way off due to the poor shape of the originals, the belt sander made "quick" work of it, and the levels bought at harbor freight for cheap made for a great straight edge, not worrying about it being level so much as flat I brought the stringers gown to where the floor would sit flat. Then reference the motor cradle measurements and make sure it's at the correct height as well.
On to the glassing. I used all epoxy resin (fiberglasssite.com had a good price) and 1700 cloth. I layed it on the fillets at 2" then 4", 8" then an all over the top layer. The 1700 cloth has multiple layers of woven cloth in it. Been very solid thus far. I didn't mention it earlier but the old bilge coating needs to be ground out with a flap disks to the clean glass underneath for a good bond (still have dust in my garage from this.)
i didnt do foam in mine so my next step was the floor. After getting my primaries and secondaries glasses in at the proper height, I took the lip of the old floor out. I was easy for me by prying it out from the underside with a thin crow bar. Idk if the glass had weakened over time or from the rot but it came out easily. I also added 5-6 perpendicular ribs outside of the secondary stringers to support the floor. (Took no pics). NOTE: after dealing with the rot and wet foam, I decided to add some drain openings. The goal was not to trap water under the floor. The idea came from the rear drain spot on the primaries. Added it to the secondaries and all the ribs. I think allowing it to drain will allow it to dry. END NOTE. cut the floor out of ply wood. Marine grade 3/4" is recommended. I used 3/4" exterior plywood (bcx has waterproof glue) coated with the epoxy resin. I glued (peanut butter) and screwed it down (stainless screws also coated in epoxy resin) to the stingers. Fill any gaps with the peanut butter Glass the joints in growing layers again up the outside edge and down over the mains.
On mine i did not build the hump under the bow, I kept the floor flat and left an opening for the vent tubes,cables and wiring as far over as possible. The floor in front of the pylon was left removable (think the rear floor) for more easily servicing parts or running wires. Angle aluminum supports the sides. A battery box was built and glasses in under the floor. Holds 2 batteries with a bit of storage space or third battery spot. Running 2 vent tubes rather then 3, stretched them all the way back to the motor (some guys fit pvc in there, flex tube was easier and cheaper). I built a box that's removeable above the floor to protect the goods.
After that hat it's a matter of finishing it, glue and carpet, I did seadek, coating the bilge and re installing parts.
In the pics you'll see mine had a few other changes done while it was under the knife, otherwise it ended up working out well. This has been long so I'm not gonna proof read it. Feel free to ask any questions.