Сlarification: the PCW abbreviation means, that this ship is a part of Pacific Confederacy World - AU, where the Peru-Bolivian Confederacy won the war with Chile in 1836-1839 and became a major (relatively, of course) South American power.
The USS "Neptune" was initially a "Kalamazoo"-class large ocean-going monitor, USS "Quinsigamond". Laid down in 1864, she was suspended in 1865, and renamed "Neptune" in 1869 (Adolph E. Borie really dislike tongue-twisting names).
In 1874, after the "Virginius" incident, the Secretary of the Navy J.M. Robson persuaded Congress to allocate funds for the "repair and refit" of old ships. In addition, he was able to solicit funds for the completion of two monitors - "Shackamaxon" (renamed USS "Hyperion") and "Quinsigamond" (renamed USS "Neptune"). In fact, the "completion" were no more real than "refit": old ships were secretly disassembled for scrap, and under the same names the new were laid.
After the Robson's machinations were revealed, Congress still decided to finish two new ships: "Neptune" and "Hyperion". The first were comissioned in 1881.
Description:
The USS "Neptune" was the large, 6050-ton monitor, protected with 356-mm compound armor belt. Two "Compound" steam machines propelled her on about 11,8 knots. Initially, the ship was supposed to have a smooth deck, but during construction it was equipped with a superstructure to improve habitability.
She was armed with the most powerfull guns avaliable: 330-mm rifled muzzle-loaders, converted from the Dahlgren 380-mm smoothbores. Three guns were placed in three centerline barbettes on the "disappearing" mounts. The additional armament consisted of four Gatling guns and bow torpedo tube.
Service:
After completion, the USS "Neptune" became the most powerful ship of the North Atlantic Squadron. She was assigned to the defense of the East Coast, and usually based on Norfolk. In 1884-1885 she made a great voyage in South America, showing the reviving power of the United States Navy to the Brazilian Empire, the United Republic of Paraguay and Uruguay, and the Argentine Union.
Despite the fact that the "Neptune" was the newest and most powerfull ironclad warship in the US navy, she has never been considered particularly successful. Her guns were nearly obsolete, their "disappearing" mounts was unreliable and prone to the mechanical fritz. In 1888, she was partially rearmed: her central 330-mm rifle were replaced by the 380-mm pneumatic "Dynamite" gun, and her auxillary armament were replaced by the 1-pdr Driggs-Schroeder guns. But she was still obsolete, and were placed to reserve in 1895.
In 1898, after the (unsuccessful) spanish attempt to ambush the US ships at Key-West, the old USS "Neptune" was recomissioned and placed on the coast defense duty in the New Orlean. She was completely obsolete by this time, and her crew grimly noted, that "
her dynamite gun was, probably, the only weapon that could do any harm to enemy." The ship never had the chance to fire her guns in anger, and was put out of comission in 1899. The sale of this ship to Mexico was discussed in 1900, but in the end, USS "Neptune" were decomissioned in 1902, and sunk as target in 1908.