Yeah that Haigh guy sounded like a used car salesman trying to pull the wool over on Emmy. 'had to add another 250 strands from what I read. 160ksi is nothing to sneeze at, certainly 180 would have been pretty special. Pretty hard stuff in the day, especially for the use. They must have got it right to stand the test of time, not only for strength but must have kept the loading very low to avoid fatigue all these years. Of course, today 160ksi or even 180 is fairly medium strength stuff and can be obtained with a medium carbon steel with something like .40 carbon.
On the boilers, I saw a "Dirty Jobs" episode where they were cleaning a ship boiler for it's annual crack inspection required by the Coast Guard.
