Does anybody know when the K-37's were fitted with steel pilot beams? I'm guessing from various photo's the mid to late 50's. I had originally thought that only the 492, 493, 497,498, and 499 aquired them but after some digging I discovered that all but the 491 got one. I can't account for the 490 or 496 since they have been scrapped. Where were they fabricated and where were they put on? Thanks for any help.
William