HMNZS Tui (1970)

Serving with the USN from 1963 to 1970, these ships were designed to perform acoustic experiments on sound transmission underwater, and for gravity, magnetism and deep-ocean floor studies.

The fourth ship to be so named by the Navy, Charles H. Davis (T-AGOR-5) was laid down by Christy Corporation in Sturgeon Bay, Wisconsin, 30 June 1962; launched 30 June 1962; sponsored by Mrs. Roy Alexander Gano, wife of Admiral Roy Alexander Gano, Commander MSTS; delivered to the Navy 25 January 1963 and turned over to the Military Sea Transportation Service (MSTS) 25 January 1963.

For years Tui went unobtrusively about the kind of work she was designed for, primarily underwater acoustics.

Tui worked in Australian, Indian Ocean and South Pacific waters.

In February 1999, Tui was scuttled 2 kilometres (1.2 mi) from Tutukaka Heads to serve as a tourist attraction and wreck for divers, following a period of work on her which removed any objects in danger of breaking free and welding shut any areas that may have posed a hazard for wreck divers.