Old ships - educate me please
One for the Navy types. I read about HMS XYZ being "old and knackered", and that means they have to be laid up and ultimately scrapped.
What is it that fails so spectacularly as to cause the vessel to be retired?
Take Invincible, for instance. Been laid up for 5 years or so, and headed for the scrapper shortly. Engines no good? Aren't they Olympus? Is it that big of a deal to replace them? While not trivial, similar engines on aircraft are changed on a daily basis around the world.
Shafts? Bearings? These are basic mechanical devices.
Maybe things like seals and pipes. Corrosion? Why not make them out of corrosion resistant alloys to begin with? Change the seals?
Electronic systems? Again, piece by piece not that difficult to repair/replace. The whole system might be a big deal, but could it be done for MUCH less than the cost of a new ship?
Things like Airconditioning, fresh water plants, motors, cranes, etc are again basic (ish) mechanical devices.
Crew accommodation, galleys, messes, these are again not big ticket items.
I find it hard to believe that a ship with a sound hull is beyond redemption. Looking at museum ships (HMAS Vampire, HMS Plymouth, USS Intrepid, Iowa battleships, USS Texas, HMS Belfast), they're not in bad mechanical condition. Maybe obsolete, and I'm sure the engines and such are rusted up through disuse, but the fabric of the ships aren't in danger of falling apart.
Is it just straight bean-counting, or is there something I am missing?