I can readily say from experience with boilers on the performance side that they dont come "down" until either "A" the blowout impeeds the performance and its pissing away more water then she taking in through make up. "B" they no longer need to rely upon it at that paticular time and can take it down. Or "C" plant outage when all repairs are made. Until then patch it up and light it off and run it until it can no longer or it jeopardizes the operation of the other equipment in its train or presents a safety risk.
The high pressure ones found aboard USN DD's i'm not so sure of but I do have experience with the 600# Babcock Wilcox series and their equipment.
I would imagine they were very simuliar to the ones your father worked upon onboard a USN cruiser. It should have been in the 600# series although probably different tube style and fuel.
And your tubes are only going to last their life with good sootblowers, blowing down tubes on a regular basis and regular maintenance. On ours the screenwall tubes were normally the first to go.