Wow, learning a lot from this thread topic. Searching "crash boat" opened up a whole new world.
Nice background article about the Model 293 that went to USSR.
http://cnrs-scrn.org/northern_mariner/vol18/tnm_18_3-4_173-184.pdf
But then found some really good stuff: http://uscrashboats.org/cpage.php?pt=10
Scroll down about halfway on the left side to "Manuals and Publications" and then select 63' Operator's Manual. I downloaded the 135 page PDF and started reading. I don't know if I could get one running, but at least I'd know where everything is located. :) It's for the Model 416, but from what I can gather all they did on the Model 293 was to block off the back hatchway and cover the whole thing with a flush deck which allowed for the enhanced armament. I don't believe they changed any of the front half of the boat or the internal bulkhead arrangement. The seams on the engine deck cover appear to be the same as shown on the other models. Anyway, hope this helps with your plans.
Jack