Mike
You are a man after my own heart.
I have worked on a similiar vessel, not a Navy lander, but a large offshore supply vessel that had similiar "doors" on the front. The hinges had worn,(actually rusted) out so bad that the doors would no longer meet and seal.
You would have loved this job I was on. In order to get all of those holes round and true, we ended up boring about 500 pounds of steel out. We kept track by putting those "figure six" shavings in five gallon buckets, We ended up with eleven full buckets, which weighed about 60 pounds each.
With the set up you see there, I could pull between 1/8 and 3/16 to the side on each cut on a 32 inch diameter. I made a compound reduction for the main gear drive to give me 32-1 reduction. That air motor you see with the two 3/4 ID air lines going is an old Ingersol Rand corner drill that I adapted a 5 hp reversable air motor to. At 110 psi, the motor runs at 220 RPM wide open. I had to re-vane the motor about 2/3 the way through. I make my own vanes out of Micarta. The bar turned between six and seven RPM. That seems slow, untill you look in there and see those chips flying off the cut. The feed was set at .016 per revolution. It took about an hour and a half to cut a five inch length.
If you look close, you will see those white circles on the face of each abutment. Those surround the "witness marks", (actually tiny center-punch marks), that I layed off of the music wire. These same marks are used to align the boring bar with a set of clipers that have a point on one leg.
Once, during the job, a couple of Engineers came up to see what we were doing. One commented that the bar turned rather slow. I told him it did seem slow, but it was relentless.........jackie