Badly Welded Man
The answer was given in the second post
The answer was given repeatedly throughout the thread.
I think you misunderstand what Keith wrote. My reading of it is that at or around 30 feet, the size of vessel he dealt with, it was accurate enough. Why should it not be accurate at smaller distances?
Microprocessors are on of the most accurate thing machined or manufactured at 0.0001” over 1”
Ships are built within tolerance of ⅛” over 300 yards.
What’s more accurate?