The USS Kentucky (BB-66) would have been the last of six Iowa class battleships. She was incomplete at the end of the Second World War, and although work continued on her intermittently until the mid-1950s with some proposals to complete her as a missile battleship she was eventually sold for scrap in 1958.
In the summer of 1940 the Navy Board agreed to build two extra Iowa class ships (Missouri and Wisconsin) under the FY41 budget. Work then began on the design of a slower battleship, the future Montana class, with hull BB-65 allocated to the new class. World events changed this plan - as the Missouri and Wisconsin were being ordered, the Germans were advancing rapidly through France. The fall of France helped convince Congress to fund an emergency naval building programme, which was authorised on 19 July 1940. The secretary of the navy decided to speed things up by repeating existing designs, and so on 9 September 1940 two extra Iowa class ships were ordered - USS Illinois (BB-65) and USS Kentucky (BB-66).
The Kentucky and the Illinois would have had improved anti-torpedo protection based on work done for the Midway class aircraft carriers during 1943.
In December 1945 the Secretary of the Navy announced that work would be suspended and that she would then be completed as an antiaircraft battleship. Work continued until August 1946, and the idea was then shelved. When work resumed in August 1948 the aim was to make the hull watertight so she could be floated out of the dock. She was moved out of the building dock on 20 January 1950. Over the next few years a number of plans were put forward to complete her as a missile battleship, but these were never accepted. The earliest dates to June 1946, and a conversion into an antiaircraft ship was given the designation SCB 19, but didn't make much progress. In 1955 the missile battleship idea re-emerged, this time combining missiles with nuclear shells. This proposal reached quite an advanced stage before it became clear that new missile cruisers were just as effective and rather cheaper, and the idea was dropped late in 1956.
In 1956 her bow was used to repair the Wisconsin after she was damaged in a collision with a destroyer. The Kentucky was now structurally complete to the third deck, but there was no real need for her. Her engines were removed and used in two fast underway replenishment ships (although this is sometimes said of her sister Illinois instead), and in 1958 she was officially sold for scrap.