Acoodring to wikipedia:

The W19 nuclear system was adapted into a nuclear artillery shell for the US Navy 16 inches (410 mm) battleship guns, the W23. Production of the W23 began in 1956 and they were in service until 1962, with a total of 50 units being produced.

The W23 was 16 inches (410 mm) diameter and 64 inches (160 cm) long, with a weight given variously as 1,500 or 1,900 pounds (680 or 860 kg) in reference sources. As with the W19, yield was 15-20 kilotons.

Do any existing sources detail if the nuclear-ship launched shells were intended as shore bombardment rounds, for use against other ships (or fleets) or for other purposes? Under whose command would these weapons have been used in the short timespan they where in service?

  • Ryan Szismanski, curator of the Battleship New Jersey which carried the W23, did a video on Project Katie and he does not have much information. youtu.be/Pq3WYY9Aiys Each ship had 10 live shells, only 50 were made.
    – Schwern
    Commented Feb 13, 2021 at 21:37

1 Answer 1


The main reason for them was simply giving the US Navy Surface Warfare community nuclear capability. Inter- and intra-service rivalry has been a very significant influence on the weapons and programs of the US armed services ever since the United States became economically powerful in the late nineteenth century.

So there probably never was a detailed plan for how to use them. Such plans aren't very useful for tactical-range naval weapons anyway, since unexpected situation show up a lot. They would have been effective for shore bombardment, which was the most likely use of big guns at the time.

The retirement date of the shells shows that they had no place in the SIOP nuclear war plan. They were retired in 1963, and the first SIOP was completed in late 1960 and implemented on July 1 1961. SIOP was updated annually thereafter, but none of the Iowa-class battleships were in commission at the time. SIOP was intended to be implemented rapidly and would not have allowed for the reactivation time for large ships, which is at least weeks.

Since the shells are too early to have been fitted with Permissive Action Links, any that were on board a battleship could have been used at the discretion of the ship's commander.

  • 1
    My hunch is that this is spot on, but do we know enough about early SIOP versions to know?
    – mart
    Commented May 2, 2018 at 14:04
  • 1
    It's deducible from logistical considerations, and I've updated my answer with more details. Commented May 2, 2018 at 15:04

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