Was Iowa's proposed sabot eleven or twelve inches?

Was the Iowa class supposed to receive an eleven-inch sabot round for its sixteen-inch guns?

The live recollection favors a twelve-inch sabot proposal, with the figure left explicitly unverified.

A viewer recalls an eleven-inch saboted projectile for the Iowa class's sixteen-inch guns. The live recollection favors a twelve-inch sabot, with an explicit caution that the figure has not been checked during the discussion. Either figure concerns sub-caliber ammunition as a route to extending battleship-gun range without changing the main weapon.