Question: Jacques Vallée describes allegations of the Montauk Project as an outgrowth of stories about a U.S. Navy destroyer escort was claimed to have been rendered what?

Context paragraphs:
Captain-class frigate: The Captain class was the designation given to 78 frigates of the Royal Navy, constructed in the United States of America, launched in 1942–1943 and delivered to the United Kingdom under the provisions of the Lend-Lease agreement (under which the United States of America supplied the United Kingdom and other Allied nations with materiel between 1941 and 1945).  They were drawn from two sub-classes of the American destroyer escort (originally British destroyer escort) classification: 32 from the "Evarts" subclass and 46 from the "Buckley" subclass.  Upon reaching the UK the ships were substantially modified by the Royal Navy, making them distinct from the US Navy destroyer escort ships.

USS Ramsden (DE-382): USS "Ramsden" (DE-382) was an Edsall-class destroyer escort built for the U.S. Navy during World War II.  She served in the Atlantic Ocean and the Pacific Ocean and provided destroyer escort protection against submarine and air attack for Navy vessels and convoys.  Post-war, she performed other tasks with the U.S. Coast Guard and with the U.S. Navy as a radar picket ship.

USS Strickland (DE-333): USS "Strickland" (DE-333) was an "Edsall"-class destroyer escort built for the U.S. Navy during World War II.  She served in the Atlantic Ocean and the Pacific Ocean and provided destroyer escort protection against submarine and air attack for Navy vessels and convoys. Post-war, she served the U.S. Navy in other tasks, including that of a radar picket ship.

Edsall-class destroyer escort: The "Edsall"-class destroyer escorts were destroyer escorts built primarily for ocean anti-submarine escort service during World War II.  The lead ship, USS "Edsall" , was commissioned on 10 April 1943 at Orange, Texas.  The class was also known as the FMR type from their Fairbanks-Morse reduction-geared diesel drive, with a type of engine used in the submarines of the time.  The FMR's substitution for a diesel-electric power plant was the essential difference from the predecessor "Cannon" ("DET") class.  This was the only World War II destroyer escort class in which all the ships originally ordered were completed as United States Navy destroyer escorts.  Destroyer escorts were regular companions escorting the vulnerable cargo ships.  Late in the war, plans were made to replace the 3 in guns with 5 in guns but only "Camp" was refitted (after a collision).  In total, all 85 were completed by three shipbuilding companies: Beth Staten Island (47), Consolidated Orange (18), and Houston (20).  Most were en route to the Pacific Theater when Japan surrendered.  One of the ships participated in Operation Dragoon and two were attacked by German guided missiles.

Philadelphia Experiment: The Philadelphia Experiment is an alleged military experiment supposed to have been carried out by the U.S. Navy at the Philadelphia Naval Shipyard in Philadelphia, Pennsylvania, sometime around October 28, 1943.  The U.S. Navy destroyer escort  was claimed to have been rendered invisible (or "cloaked") to enemy devices.

RPS Rajah Soliman (D-66): RPS "Rajah Soliman" (D-66) was a destroyer escort/frigate that served with the Philippine Navy between 1960 and 1964.  A "Buckley"-class destroyer escort , it was originally named  during its previous service with the United States Navy.  It was the first destroyer escort to be operated by the Philippine Navy, and is the only member of its class ever operated by the service.  "Rajah Soliman" was also the flagship of the Philippine Navy during its time in commission, which ended with the sinking of the vessel in 1964.

USS Tabberer: USS "Tabberer" (DE-418) was a "John C. Butler"-class destroyer escort acquired by the U.S. Navy during World War II.  The primary purpose of the destroyer escort was to escort and protect ships in convoy, in addition to other tasks as assigned, such as patrol or radar picket.  Post-war, after active participation in the Pacific War, her crew returned home with four battle stars and a Navy Unit Commendation to their credit.

BRP Rajah Humabon (PS-11): The BRP "Rajah Humabon" (PS-11) is a former destroyer escort of the United States Navy and is now a frigate of the Philippine Navy.  It is the last World War II-era destroyer escort/frigate active in its fleet and is one of the oldest active warships in the world.  She is one of three ex-USN "Cannon"-class destroyer escort s that served the Philippine Navy.  The others being BRP "Datu Sikatuna" (PF-5/PS-77) and BRP "Datu Kalantiaw" (PS-76).

Montauk Project: The Montauk Project is an alleged series of secret United States government projects conducted at Camp Hero or Montauk Air Force Station on Montauk, Long Island, for the purpose of developing psychological warfare techniques and exotic research including time travel.  Jacques Vallée describes allegations of the Montauk Project as an outgrowth of stories about the Philadelphia Experiment.  The history of the Montauk Project story is closely associated with — and often believed to originate in — by Preston Nichols.

USS Raymond (DE-341): USS "Raymond" (DE-341) was a "John C. Butler"-class destroyer escort acquired by the U.S. Navy during World War II.  The purpose of the destroyer escort was primarily to escort and protect ships in convoy, in addition to other tasks as assigned, such as patrol or radar picket.  Post-war, she returned home proudly with five battle stars to her credit, including credit for her striking a Japanese cruiser with her 5 in guns during the Battle off Samar.  The destroyer escort was named for Reginald Marbury Raymond, who was killed by enemy gunfire on 30 April 1943 aboard USS "Scorpion" .

Supporting paragraphs: Montauk Project Philadelphia Experiment
Answer: invisible