I was brand new on a 637 class and we were about to get underway. A veteran 2nd class asked me to go with him to finish the PM's. We got to the SINS cabinet and he started to open it. I questioned him since there was a warning label on the door. He said no problem, he had done this all the time (in port). As soon as he opened the door, we heard a %$#)*()*{. Censored for family audience.
We had SINS on my first boat. One time, I was helping replace that Selectric (no proportional fonts) that prints out the SINS info. The Nav ET didn't get the D-cable JUST RIGHT and tumbled all four gyros.
Since you know where the SINS binnacle was, that was where they put the IMU mount for the ESGN. The IMU was field replaceable - just lower the bad one and hoist up the replacement. The ET's where putting up the new one when it...uh...slipped. It bounced twice on the ladder, off the bulkhead at the bottom, into the Wierdroom passage and into the NAV's stateroom.