Thanks Shrew, I have a rough idea where the stringers run. It's more their thickness and their widths apart that I was hoping to find specific details for. I have found a thread on here where someone has removed the deck, but it's an older model with an outboard (nice for insights though). There were some large box sections under the cabin seat area I wasn't expecting to see.
With regards to the bulkheads, I can see the ones containing the inboard petrol tank, and within the locker, but wasn't sure if these run full width of the boat, or just the central bilge area and locker sections?
I'm looking to fit some hatches in the rear engine bay area, in this location (see attached image). This position should be between a set of stringers if my calculations are correct.
However, I am now wondering if the 6" version may be to large and cause structural issues? Wondering if a 4" version maybe a better choice in this area and put the 6" ones under the cabin seats?