Thursday, March 21, 2013

Whither the aircraft carrier?

Wired had a piece here.  It make some good points.  The United States (richest nation on earth) can only afford 10 or 11  full sized carriers.  Should enemy subs or missiles or mines or land based aircraft get lucky, then the US is out of seapower for all the years it takes to build new carriers.  There is much to be said for cheaper vessels, of which we can afford lots of. 
   The Wired writer doesn't understand a number of things.  Steam catapults need a steam power plant to furnish the necessary steam.  It takes a lot of steam to hurl a 20 ton loaded aircraft fast enough to make it fly.  Smaller lower cost ships tend to have gas turbines or even diesels rather than expensive steam plants.  A low cost carrier cannot have a steam catapult and remain low cost. 
   In addition to the catapult, aircraft carriers must steam at full speed into the wind when launching aircraft to generate enough wind over the deck to get heavily loaded aircraft into the air.  The big carriers can all do better than 30 knots which takes a huge engine plant.  Again, a low cost carrier (they called them escort carriers in WWII) cannot have that kind of engines and remain low cost. 
  So, the low cost carrier cannot support the high performance jet fighters needed to keep enemy aircraft away.  They will be limited to helicopters, jump jets, and some yet-to-be built propeller aircraft.  They will depend upon land based air or full sized carriers, or missiles for protection against enemy air attack.  Still, such a ship can be very useful.  In fact the Navy has built a number of them, they are called helicopter carriers. 
  One other thing the Wired writer doesn't understand.  Subs, especially nuclear subs, are terribly expensive.  A sub costs five to ten times what a surface vessel costs.  Building subs just to carry Tomahawk cruise missiles is expensive.  The US Navy only has such subs because it found itself with a bunch of big ballistic missile subs left over from the Cold War.  They weren't needed anymore to deter the Soviets, they were too new and too expensive to just scrap, so they loaded them up with Tomahawks.   They did this because they had the subs, all built and paid for, not because it was economical.  In fact, Tomahawk missiles cost $1 million apiece, there are few targets out there worth $1 million. 

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