I think my dad was around 5'10" or something like that.

For training, what he said is that they all had three(?) areas/responsibilities that they were trained in so that if someone got sick or died someone was available to take their place.

One of his jobs was actually to maintain one of the first computers installed on a submarine. He told an admiral that it was a big piece of shit because he spent half of his time replacing burned out vacuum tubes. The computer analyzed ship sounds (screw, engine) and could tell them the ship that was passing overhead.