Question: USS Anacapa was what type of heavily-armed merchant ship?

Context paragraphs:
USS Altair (AK-257): The second USS "Altair" (AK-257) was a United States Navy "Greenville Victory"-class cargo ship in commission from 1952 to 1953.  She was converted into a "Antares"-class general stores issue ship (AKS-32) in 1953 and was in commission as such from 1953 to 1969, seeing extensive service during the Cold War.  Prior to her U.S. Navy career, she had operated as the merchant ship SS "Aberdeen Victory" during the latter stages of World War II.

USNS Observation Island (T-AGM-23): USNS "Observation Island" (T-AGM-23) was built as the Mariner-class merchant ship "Empire State Mariner" for the United States Maritime Commission, launched 15 August 1953, and operated by United States Lines upon delivery on 24 February 1954, making voyages for the Military Sea Transportation Service (MSTS) until going into reserve at Mobile, Alabama on 9 November 1954.  Title was transferred to the United States Navy on 10 September 1956 and, after conversion, the ship was renamed "Observation Island".  On commissioning the ship was classified as the "experimental miscellaneous auxiliary" (EAG), USS "Observation Island" (EAG-154) supporting fleet ballistic missile development.  On 1 April 1968 "Observation Island" was redesignated as a miscellaneous auxiliary USS "Observation Island" (AG-154).  "Observation Island" was decommissioned and placed in reserve from 1972 until 1977 in the Suisun Bay Reserve Fleet until withdrawn and then returned in 1978.  The ship was permanently withdrawn April 1979 and placed in service with MSTS successor, the Military Sealift Command.

SS Michael E: SS "Michael E" was a  GRT cargo ship that was built in 1941.  She was the first British Catapult Aircraft Merchant ship: a merchant ship fitted with a rocket catapult to launch a single Hawker Hurricane fighter to defend a convoy against long-range German bombers.  She was sunk on her maiden voyage by a German submarine.

USS Antares (AK-258): The second USS "Antares" (AK-258) was a United States Navy "Greenville Victory"-class cargo ship in commission from 1952 to 1959.  She was converted into a general stores issue ship (AKS-33) in 1959-1960 and remained in commission as such until 1964.  She saw extensive service during the Cold War.  Prior to her U.S. Navy career, she had operated as the merchant ship SS "Nampa Victory" during the latter stages of World War II and in the years immediately after the war.

Q-ship: Q-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks.  This gave Q-ships the chance to open fire and sink them.

USS Delta (AR-9): USS "Delta" (AK-29/AR-9) was the lead ship of her class of repair ships in the United States Navy during World War II.  She was originally built as the merchant ship SS "Hawaiian Packer" before her requisition by the U.S. Navy in 1941.  Before conversion to a repair ships, "Delta" briefly served as a U.S. Navy cargo ship.

Auguste (ship): Auguste was a full rigged sailing ship which sank at Aspy Bay, Cape Breton, Nova Scotia in 1761 while carrying exiles from the fall of New France.  "Auguste" was a former French privateer ship which had been captured by the British and converted to a merchant ship.  In September 1761, she was hired by the British government to transport French exiles and prisoners of war from Montreal to France.  For the voyage, she was under the command of Joseph Knowles, an English sea captain.  The ship was unarmed and carried 121 passengers and crew.  Almost immediately upon clearing the mouth of the St. Lawrence on October 28, she encountered a week of contrary winds followed by a nor'west gale and heavy seas which badly damaged the ship.  Leaking heavily with an exhausted crew and damaged rigging, the captain sought a sheltered harbour in Cape Breton, Nova Scotia.  However Knowles was unable to find a safe refuge as "Auguste" carried only charts of the French coast.  The ship struck land on the northeastern side of Cape Breton Island near an inlet known as Aspy Bay.  Only seven of the 121 made it to shore alive.  These included the captain, the merchant Luc de la Corne, two soldiers, two servants, and one discharged soldier.

Callao affair: The Callao affair occurred in November 1820, during the Peruvian War of Independence.  It began when a Spanish fort opened fire on the United States warship USS "Macedonian".  Though the ship was damaged, the Americans did not violate their neutrality by counterattacking.  On the following day, a boat filled with United States Navy sailors was attacked, resulting in the deaths of two seamen and the wounding of eight others.  Two days after that, an American merchant ship was attacked and her crew had to abandon ship.  Ultimately, there was no significant response by the United States to the attacks on their shipping and their citizens, though the Spanish government vowed to punish the perpetrators.

USS Anacapa (AG-49): USS "Anacapa" (AG-49) was a Q-ship in the United States Navy.  She was named for Anacapa, an island near the coast of California.

SS John W. Brown: SS "John W. Brown" is a Liberty ship, one of two still operational and one of three preserved as museum ships.  As a Liberty ship, she operated as a merchant ship of the United States Merchant Marine during World War II and later was a vocational high school training ship in New York City for many years.  Now preserved, she is a museum ship and cruise ship berthed at Clinton Street Pier 1 in Baltimore Harbor in Maryland.

Supporting paragraphs: USS Anacapa (AG-49) Q-ship
Answer: Q-ship