What's an "outrigger" for parking aircraft on a carrier? In this picture of the USS Intrepid (CV-11), there appears to be an aircraft parked with the tail hanging off the deck:


(Source)

The caption gives a clue:


  The U.S. Navy aircraft carrier USS Intrepid (CV-11) operating in the Philippine Sea in November 1944. Note the Grumman F6F Hellcat fighter parked on an outrigger forward of her island.


This "outrigger" appears to be some sort of triangular structure to partially support the aircraft's weight:



Further research, however, turns up no more information about this "outrigger." So:


What exactly was this device?
How was it used?
What's its history?
Who manufactured it?
You can see it a bit better in this picture: 



(Source)


  In order to save deck space for operations, the smaller escort
  carriers like HMS Khedive used outriggers. The tail wheel is first
  affixed and locked to the rigger trolley and then the aircraft is
  pushed outwards and the wheels heavily chocked fore and aft of the
  wheels. Here one of Khedive’s Corsairs demonstrates the concept
  perfectly. Note that the Corsair has Type C roundels, indicating it is
  in the European theatre of operations.


They were effectively a simple way to save deck space with out enlarging the deck. There is another decent pic here and some spitfires on outriggers here

Based on the info here they can be found as far back as the late thirties


  It represents an F4B-4 positioned on an experimental outrigger aboard
  the USS Saratoga during the late 1930s. The Saratoga and several other
  aircraft carriers were selected to try out different types of deck
  outriggers for the Navy in the interwar era.