In order to use a scrap piece of 1/4" plywood for the seat, I rabbeted the seat bottom frames and deck beam to utilize an 8' long strip of plywood only 12 1/2" wide. I used a forstner bit to bore some half round drain holes at the junction of the seat bottom and seat back to allow any water that gets on the seat to drain through. I plan on having upholstered seat cushions at some point, but wanted a functional and structural seat in place without the cushions.
After flipping the boat, it was time to figure out what to do next. The carlings had to go in as they provide the structure for between the main deck beam and the transom. After planing some honduras mohogany down to 5/8" thick, it did not want to bend into position so I got out the soaking pipe and rigged it into the stairwell again and soaked the wood for a day. I rigged up some extensions so the carlings could be pulled into the proper curve above the boat, let dry, and then marked and trimmed to fit. It required some creeping up on compound angle cuts until the angles and length were slowly tuned in.
A mid-front deck beam was added per the plans and then I decided to create an auxiliary dash beam to support the deck strongback (longitudinal middle support) and deck battens so the dash could be made removable while designing and fitting in place. The dash is at a 20 degree angle and I'm using Teleflex steering "The Rack" mounted upside down so the cable routes inward and loops under the deck following Squirt builders Bill & Linda Whitney in Glen-L's WebLetter 65.
I did a lot of playing around with mocked up seat boards after getting the steering wheel in place to determine seat fore-aft location. Then after a lot of circular thinking and planning, eventually built the seat bottom and put in a couple of holes for holding drinks or whatever. With the seat bottom in place I can finalize the seat back angle and mid deck beam.
With the motor mounted I figured out where to place the rear most beam while allowing a 6 gallon gas tank to be loaded in between the beam and transom and slid into the corner. It's a bit tricky due to the transom knee, but can be done. I'm planning to build a two door hatch in the deck that opens from the center and hinges to each side. The thought is to allow the center of the boat to open up without the hatch lids being in the way and permit easier access to the outboard since it is a manual start. I also am planning the hatch to allow loading a 6 gallon tank as once all the remote connections to the outboard are mounted, I'm not sure if the back will still be easily accessed. I added the corner radius reinforcements to the opening and added short beam extensions to tie the rear beam and carling to the shear. With these bits in place, the improvement in rigidity of the structure is amazing. I'm working on the corner radius pieces at the dash and then it will be time to tackle the hatches.