Unclassified (IX), Special Types
1917-1919
On Hand 1920-1922
1922-1945: Large Special IX
1922-1945: Small Special IX
Other IX (Special) Hull Numbers, 1920-1945
Notes: IX 165, 166, 170-172, 183, and 195 were ex converted minesweepers (AM). IX 175-177, 180, 181, 194, and 203 were ex converted coastal minesweepers (AMc). IX 202 and 230-232 were ex Navy-built coastal minesweepers (AMc-36 class).
IX was not a formal ship type symbol until 8 January 1941. Previously it was only a symbol in the Navy Filing Manual for storing correspondence relating to ships listed on the Navy List as "Unclassified." File numbers IX 1-32 appear to have been assigned by the time the July 1922 Ships Data Book was drafted as they match the order of the "Unclassified" list in that volume. The last Navy Filing Manual to appear before January 1941 was the 1939 edition, in which the highest IX symbol was IX-40.
The file symbol IX-16 may have been used for Tallahassee (ex BM-9) before it was used for Kearsarge. Tallahassee was transferred to the "Unclassified" list on 1 July 1921 but was gone by the time the July 1922 Ships Data Book was published, having been sold. The IX-16 symbol is known to have been used for Kearsarge in 1926. A new file symbol, AB-1, was probably created for her in the 1931 edition of the Navy's Filing Manual, and it first appears as a formal ship type symbol in the unpublished 1942 Ships Data Book.