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16) Fort Tilden's Harbor Entrance Control Post
(Advance HECP #2)

Updated: January 24, 2001

The New York Harbor Entrance Control Post (HECP) was located at Fort Wadsworth in Staten Island, NY. The Advance HECP #1 was located at Fort Hancock, Sandy Hook, NJ, while the Advance HECP #2 was located at Fort Tilden in Rockaway, NY. These HECP facilities served to control and coordinate the joint task of harbor defense among the US Army and the US Navy. Each was staffed by officers from both services. The HECP at Fort Tilden handled the East side of the Ambrose Channel of the New York Harbor.

A casemate in Fort Tilden served as the Advance #2 Harbor Entrance Control Post (HECP) for the New York harbor during World War II. It went into operation on August 6, 1943, although construction was not completed until December 13, 1943.

Installation of the 50 foot observation tower, located behind the HECP casemate, was started on March 13, 1943, and completed in September 1943. This tower had an electrically heated, wooden topside structure, approximately 16 feet square, with a 2 and 1/2 foot wide catwalk that extended around the structure. The tower was constructed by the Ordnance Department for use at the Sandy Hook Proving Ground. When the Proving Ground was discontinued in 1919, the tower was transferred to the Coast Artillery and pedestals and fire control optical instruments were installed by the U.S.E.D. in 1926.

The function of the HECP was: "to collect and disseminate information of activities in the defensive sea area, to control unescorted commercial shipping in the defensive coastal area, and to take prompt and decisive action to operate the elements of the harbor defense, in order to deny enemy action within the defensive coastal area".

The HECP was also tasked with maintaining a navigable entrance to the New York harbor by preventing enemy ships from laying mines or scuttling themselves to block the harbor entrance.

The Advance HECP #2 at Fort Tilden was used to identify ships approaching the Ambrose Channel from the waters off Long Island, and to keep fishing vessels and pleasure craft out of the restricted areas off the shores of Fort Tilden. The Advance HECP #1 at Fort Hancock performed similar duties on the West side of the Ambrose Channel. This structure was built into the remains of Battery McCook (8, 12" Mortars, 1898-1923).

When an unidentified vessel entered the defensive area, the HECP would direct a blind challenge, if an immediate response to the proper code was not received the HECP would organize a powerful offensive attack. If the harbor surveillance radar indicated that a surface ship was approaching, the area was illuminated with spotlights, and a warning shot was fired from the coastal gun batteries. If the intruder failed to stop, the batteries would open fire upon the ship. If the intruder did stop, a patrol vessel would be dispatched to investigate.

If the unidentified vessel was detected by the undersea magnetic detection equipment and no surface ship was detected by radar, a submarine was presumed to be in the harbor. Any friendly vessels approaching the harbor were advised to stay clear of the harbor, the harbor patrol was notified and the submarine net gates were closed.

All communications were conducted by landline telephones, backed up by two-way radio equipment. Light and flag signals could also be used for communications. A staff of four officers and 20 enlisted men were authorized for the HECP at Fort Tilden.

Fort Tilden's HECP was located in a casemate equipped with a ventilation system designed to protect the occupants from poison gas attacks. Plumbing, electrical, communications, and dehumidification systems were installed to serve the staff and equipment. The casemate contained two large rooms designated Room A and Room B, an enlisted men's latrine, an officers latrine, a radio room, and a central corridor. The casemate had it's own boiler room, coal bin, cable hut, and is accessed through an air lock. The floors were covered with linoleum tiles and the ceiling was covered with 2" acoustical material.
Fluxmeter and recorder installed in HECP casemate.
Fluxmeter and recorder installed in HECP casemate
(US Navy photo)

Three fluxmeters and recorders installed in observation tower.
Three fluxmeters and recorders installed in observation tower.
(US Navy photo)

Details of fluxmeter and recorder installed in observation tower.
Details of fluxmeter and recorder installed in observation tower.
(US Navy photo)

Fort Wadsworth HECP.
HECP Signal Tower, Fort Wadsworth, NY, 1942.
(Bernard Norris photo)

Fort Wadsworth HECP.
Signal light at HECP Signal Tower, Fort Wadsworth, NY, 1942.
(Bernard Norris photo)

Fort Wadsworth HECP.
Courtyard within Fort Tompkins as viewed from HECP, Fort Wadsworth, NY, 1942.
(Bernard Norris photo)

Fort Wadsworth HECP.
USS Aquatania entering NY Harbor, viewed from HECP, Fort Wadsworth, NY, 1942.
(Bernard Norris photo)

HECP Equipment
QCP HERALD Hydrophone equipment.
(US Navy photo)

HECP Equipment
QBC-1 HERALD Hydrophone equipment. This unit was mounted on the harbor floor and acted as a directional hydrophone.
(US Navy photo)

HECP Equipment
This RBF-1 was a rack of VHF radio receivers that was used to listen to signals from up to 10 sonobuoys.
(US Navy photo)
HECP Equipment
Type JM sonobuoys were floating hydrophones and radio transmitters that sent audio signals back to the HECP for analysis by Navy Soundmen. These were anchored into position and required periodic battery replacement.
(US Navy photo)


This is a portion of a history of the New York Harbor HECP (circa 1945). The complete report is available at Fort Tilden.
Advance HECP went into operation on 6 August 1943 at Fort Tilden, Rockaway Point, Long Island, New York, an Army fort constructed at the time of World War I and greatly expanded during this war. Preliminary surveys for the installation of this HECP unit considered a structure on the top of the Half Moon Hotel, Coney Island, or the Army Radar Tower, Fort Tilden, which had an elevation of 173 feet. Both these sites, however were rejected in favor of its final location, as more central for joint Army-Navy action.

a. Mission
The principle tactical mission of Advance HECP #2 was to establish the identity and to determine the character of the ships passing along the Long Island shore before approaching Ambrose or Rockaway Channels. Its main secondary mission was to prevent fishing vessels and pleasure craft from entering the restricted area before the Fort Tilden gun emplacements.

b. Operations:
1. Ship plot was maintained in the contiguous waters.
2. Unit 3-C (Navy operated loop station) was operating in conjunction with this HECP, unlike Naval Unit 3-A at Sandy Hook. (For further information see Section on MAGNETIC INDICATOR LOOPS.)
3. A radar sweep was theoretically possible by means of an auxiliary SN radar unit, but actually this unit was unsatisfactory in operations, as it rarely could reach out to the extent of the loops, (as explained in the section on RADAR).

c. Operations Office Space:
Joint Army-Navy Operations Room, occupied 6 August 1943 and wholly completed 15 December 1943, 400 square feet of floor space, 4,000 cubic feet of space, located in bomb proof center built by Army for HECP and Command Post, heated by forced warm air heat; Tower and Generator shack (Army owned and erected for HECP and Command Post.) Tower located back of bomb proof, 50 feet in height, electric units heated topside structure, 256 square feet of floor space, 2400 cubic feet, 2 catwalk on outside, 4 sides 43 feet high, 60 feet above. Used head in bomb Proof shelter.

d. Personnel:
Total complement authorized was four officers and 20 enlisted men. Enlisted men were housed in a double deck Army barracks and messed with various Army batteries until August 1944, at which time they were transferred to the Fort Tilden Coast Guard Station mess to give them the benefit of the best possible mess. Officers were housed in Army Bachelor Officers' Quarters and messed with Fort Tilden Army Officers mess. Recreational facilities of the Army at Fort Tilden were made available to all Naval Personnel on duty there. The station beach, which included three clubhouses, one for officers, one for a searchlight moved down from Fort Tilden, to serve as a Navy Signal and Mine Watching Station, it the ship traffic required an extension of the existing signal system, but this contingency did not come to pass, and the tower was never regularly operated. The authorized enlisted complement was as follows: 1 CBMA, 6 SoMH2c,, 4 SoMH3c, and 1 SC-Striker-S2c; total 13.

d. Naval Unit 3-C, Fort Tilden, Rockaway Point, New York:
This Unit was set up under orders of 11 December 1941, providing for magnetic loop installations for New York Harbor. This station was located at Atlantic Beach Coast Guard Station on Far Rockaway Inlet, Atlantic Beach, Long Island. At this time the station was known as Naval Unit -#2. Two magnetic loops were laid, known as Loops 3 and 4. The shore equipment consisted of three fluxmeters, two in use and one spare, and telephone communication to HECP at Fort Wadsworth. A fluxmeter and visual watch was maintained by one chief and eight seamen starting 14 March 1942.

All crossings on loops were reported by telephone to HECP and the visual watch attempted to identify the ships making the signatures, Because of technical difficulties experienced, due to nearby railroad (discussed below,) it was decided to move the station from Atlantic Beach to Fort Tilden. Concomitantly it was decided to improve the procedure of reporting the movement of vessels in New York Harbor by the establishment of two advance HECPS. Shortly after 17 September 1943, Naval Unit #2 became Naval Unit 3-B and was set up as an organization separate from the Advance HECP #2, but working closely with it. In place of the two unsatisfactory loops (Numbers 3 and 4) originally laid from Atlantic Beach, three loops were laid with Fort Tilden as the shore terminus. When completes the loop system had as its approximated eastern edge, a line from the HECP Tower to the Ambrose Lightship. The tail cables were brought into a bombproof shelter where four fluxmeters were located. Subsequently it was decided to relay three new loops in place of the original two. The new loops gave excellent results. Loop 4 was able to operate at the highest sensibility most of the time and loops 5 and 6 gave fine results, but being closer to shore experienced greater disturbances than loop.

4. The limitation of these loops were only those of the system and the equipment used. A more sensitive loop could have been used. Clear signatures were obtained on all but the smallest trawlers used in fishing and 38-foot, private cabin cruisers. Multiple turn loop systems with discriminators could probably pick up these craft. The water conditions on the eastern side of the harbor are very favorable to the use of loop equipment. The loops laid across the Western Approaches to the New York Harbor (Shore Terminus; Spermacetti) gave satisfactory performance. On 12 April 1945 Loop 3 was put out of operation when the outer leg of the loop was cut by a ship dragging anchor. This was never repaired, and shortly after cessation of hostilities in the European theater, on 28 May 1945, all loops were secured. In the final analysis it is the opinion of the last Officer in Charge at Fort Tilden that magnetic indicator loops were the most successful of all detection devices used in New York Harbor as their findings were scientifically exact, and independent of human analysis.

e. Difficulties Experienced in Loop Operation in New York Harbor:
(1) When the loops were first laid from Atlantic Beach and Spermacetti Cove, none of the men were familiar with the equipment with which they were working. In addition, visibility was such that it was often almost impossible to identify vessels at any great distance during the day and totally impossible at night.

(2) The original loops (out of Atlantic Beach) were far too long and were not laid tightly enough. The cable could swing with the sea action, causing wide swings of the recorder pens.

(3) It was also found that the Long Island Railroad, which ran an electric line that paralleled a mile of the tail cables, caused even more perturbations. The smallest ship that could be picked up by the installation was a harbor tanker. Even these signatures were very difficult to distinguish from the disturbances recorded. They could only be identified by the shape of the signature as the magnitude was not greater than that of the perturbations. The watch standers became skilled at distinguishing signatures but at no time could confidence be placed in the results obtained by the Atlantic Beach Station.

(4) The greatest and most crushing difficulty was the destruction of loops by merchantmen dragging anchor in restricted cable areas. (These ships were anchoring in restricted cable areas up to the last week of HECP's operation, despite all warnings and protests.

(5) Much intelligence gleaned from loop signatures was obscured, reduced in value, or rendered useless, multiple loop crossings. These uncontrolled crossings continued up to the time the loops were secured. In order for loop signatures to of maximum intelligence value, it is necessary for traffic to be so regulated that not more than one ship at a time crosses a loop.

(6) From time to time there have been unverified loop signatures, which after deliberation and experience, were believed to have originated spuriously due to shifting of the earth's magnetic field.

f. Experimental Loop for Distinguishing Inbound from Outbound Traffic:
ComTHREE letter dated 15 December 1943, subject Underwater Magnetic Indicator Loops, Determining Direction of Crossing, make reference to permission granted by Vice Chief of Naval Operations to "install a trial loop (unequal area) in outer New York Harbor," and further stated that VCNO had "requested the Commandant, Navy Yard, New York to make this installation inside of Loops #2 and #3." It went on to say this trial loop was laid at a designated spot and terminated at Naval Unit 3-A Spermacetti Cove, New Jersey. (See Appendix FF.)

(1) ComTHREE letter dated 4 February 1944 addressed to BuShips, tells of the success of the trial loop: "Definite indication of direction was obtained with this trial loop as evidenced by enclosure (1), a photostatic copy of a sample signature on fluxmeter tape, giving authentic evidence of desired results, which shows typical signature of an inbound and an outbound vessel." (See Appendix GG.) The trial loop was laid with the distance between the center leg and outer legs. Therefore, an outbound vessel makes a signature wherein the time required to cross between the inner and center legs is approximately twice that required for crossing the center to outer legs. An inbound vessel gives a reverse type signature.

(2) "On 3 January 1944, ships anchoring in a northeasterly storm, dragged anchor and cut all three legs of this loop. As other ships also damaged tactical loops #2 and #3, priority was given to the repair of those loops prior to repair of the test loop." (Trial loop was never made workable again.) Loops #2 and #3 were repaired 28 February 1944.

(3) Although the exact dates on the Unit 3-C log is not now available, it was learned through telephone conversation with an officer in the Radio Material Office that loop 2 had all three legs out by a ship dragging anchor in the fall of 1943 at about the same time loops 3 and 4 were being picked up at Atlantic Beach.

(4) Technical consideration made it advisable to create two loops in place of the one damaged loop 2, this being done by running out another tail cable.

(5) As a result, the loops monitored at Spermacetti were redesignated as follows: loop 1 remained same; loop 2 make into two loops became 2A and 2B, When the loops at Atlantic Beach were picked up, and three new ones subsequently laid, these were designated 4, 5, and 6. In line with this changes loops 2A and 2B were redesignated 2 and 3 respectively.


New York Harbor hydrophones were Army installed and Army operated. (For approximate positions see Appendix B.) Located on the ocean bottom, the acted like large telephone earphones and were wired into a "squawk box" located in the mine case mates at Fort Wadsworth, Fort Hancock, and Fort Tilden. Hydrophone signatures were essentially as difficult to analyze as sono-bouy findings, due to the heavy traffic of New York harbor in constant movement. A destroyer might be calibrating off Cholera Banks and drop a practice exercise "ash can." Any hydrophone was sensitive enough to record it, way back in the Narrows. But although the hydrophone signature made it known that an underwater explosion had occurred, a basic operational inadequacy lay in the fact that there was no way of knowing from which direction or at what distance that explosion occurred. In the course of the war, the positions of the hydrophones were moved many times. In actual operations they proved of doubtful value.

Furthermore, no real attempt was known to have been made by the Army to tie them in with HECP activity.


The nets and booms of New York Harbor were laid by the U.S. Navy Net Depot, Bayonne, N.J., and came under the command of Commander Ambrose Section although the two net vessels came under the tactical command of HECP Fort Wadsworth. These vessels consisted of the YNG-3, whose chief function lay in assisting when the net gates were closed and opened, and the YNG-39, the "flag" ship, whose signal bridge was manned 24 hours a day, always by one man but in heavy traffic by two men. (For relative position see Appendix B. For detailed construction see Appendix EEE.) Neither of these vessels had any propulsion but were moved by tugs. Each had a power generator for electricity and steam. The YNG-3 was put into position on 27 November 1941; then at a later date the YNG-39 was added, taking the old position of the YNG-3 on the west side of the Channel.

a. Functions of Net Vessels:

(1) The first function of these ships was to control the net gates, of which there were two. In the early stages of the war the main gate was usually closed from about 0000 to 0300, but later when convoys were routed to depart late at night it became the practice to leave the gate open at all times, except in emergency on order of the HECP. The auxiliary gate when installed was open only when large convoys were in movement, and was operated by a third YNG put into position in the spring of 1944.

(2) The second function of these vessels was to assist in the identification of harbor traffic. Each ship, whether inbound or outbound, was challenged before she reached the gate. Flags were used by day, blinkers by night. Movements were regularly checked with both the Ambrose Guard Vessel and HECP, Fort Wadsworth.

(3) A third and highly strategic function was to provide a watch by means of underwater sound gear. The YNG-39 was equipped with both listening and ASDIC devices. During poor visibility she maintained a constant search to the seaward.

(4) A fourth and purely courtesy function of the net vessels was to assist the Degaussing Section at Swinburne Island by directing vessels to the proper area for degaussing. (See Section on SHIP INFORMATION PROCEDURE.)

b. Communications:
The YNG-39 possessed one Magneto type telephone circuit, Navy laid, to Hoffman Island, which provided direct communication with HECP, Fort Wadsworth and with Swinburne Island. She had no radar and only a small radio transmitter and receiving set, suitable for conversation with the HECP Roving Patrol YP's and with HECP Fort Wadsworth. The YNG-3 had neither a telephone or a radio and relied purely on visual signaling with the YNG-39 for her communications.

c. Armament:
The YNG-39 was armed with one 50-caliber machine gun, two 30-caliber machine guns and one 1-pounder or "heave to" gun. The YNG-3 was unarmed except for Thompson machine guns. To maintain the ship in a state of readiness the YNG-39 in the early stages of the war called "general quarters" once a day.

d. Personnel:
Personnel consisted of two officers and eighteen to twenty-two enlisted men. All enlisted men were assigned from the Naval Frontier Base, Tompkinsville, Staten Island. The watch bill was so arranged that each man had six days aboard the net vessels and two days ashore. Nobody took regular watches except the signalmen on the bridge who stood four hours on and twelve off. When the net vessels were first put into operation all personnel was white; in February 1943 the first Negro personnel were put aboard, and finally all enlisted personnel were Negro. Sometime after VE Day (exact date unknown) the Coast Guard too over the operations of the vessels at which time all Naval personnel were removed.

e. Harbor Transportation:
Transportation to and from the shore was provided by a YP from the Naval Frontier Base, which was also responsible for bringing out the food and other ship's supplies.

f. Disestablishment:
The YNG-3 was left temporarily at the Narrows while the YNG-39 was given a complete overhaul, and her winches removed. From 28 July 1945 the YNG-39 then resumed her former position in the Narrows as a traffic control vessel.
(End of report)

Other HECP Locations

Many HECPs were established at critical harbors on the Atlantic and Pacific coasts of the United States and it's territories:

District # ---- Station ----- Location ----------- Latitude - Longitude
1 -- Portland, ME -- Fort Williams -- (N43-37-15, W70-13-00)
1 -- Portsmouth, NH -- Ex-Coast Guard Station (Fort Stark, Battery Kirk) -- (N43-02-30, W 70-42-00)
1 -- Boston, MA -- Fort Dawes -- (N42-21-30, W57-30)
1 -- Newport, RI -- Beavertail -- (N41-27-00, W71-24-00)
3 -- Fishers Island -- Fort HG Wright -- (N41-15-22.8, W72-01-23.9)
3 -- Staten Island, NY -- Fort Wadsworth -- (N40-36-15, W74-03-22)
4 -- Delaware -- Cape Henlopen (Fort Miles) -- (N38-47-39, W75-05-32)
5 -- Norfolk, VA -- Just outside Fort Story -- (N36-55-48, W76-00-42)
6 -- Charleston, SC -- Fort Moultrie -- (N32-45-33, W79-51-31)
7 -- Key West, FL -- To be established
8 -- Santa Rosa Island, FL -- (Fort Pickens, Battery Worth) -- (N30-19-30, W87-17- 30)
8 -- Galveston, TX -- Fort Point (Fort San Jacinto) -- (N29-20-00, W94-44-37)
10 -- San Juan, PR -- (Fort Brooke, El Morro) -- (N18-28, W66-07)
10 -- Vieques Sound (Roosevelt Roads), PR -- Punta Algodones
11 -- San Diego, CA -- (N32-40-19, W117-14-24)
11 -- San Pedro, CA -- Fort MacArthur (Battery Leary and Merriam) (N33-42-42, W118-17- 32)
12 -- San Francisco, CA -- Fort Winfield Scott (Dynamite Battery) -- (N37-48-08.3, W122-28- 32.7)
13 -- Columbia River -- Fort Stevens (Battery Mishler) -- (To be established)
13 -- Puget Sound Area, WA -- Fort Worden -- (N48-08-30, W122-46-00)
14 -- Pearl Harbor, HI -- NavyYard Pearl Harbor -- (N21-21-11.9, W157-57-26.2)
15 -- Cristobal, Panama Canal Zone (Atlantic Side) -- Fort Sherman -- (N9-22-00, W79-57-00)
15 -- Balboa, Panama Canal Zone (Pacific Side) -- Fort Amador -- (N8-55-00, W7931-00)
16 -- Manila Bay, Corregidor -- Fort Mills -- (N14-22-59, E120-34-23)

Note 1: Lat-Long coordinates are provided for plotting purposes, to locate sites with GPS navigation units, and to utilize the Microsoft Terraserver Satellite photograph database.

Note 2: Comments in italics added by author to reflect actual locations.

If you have any information on the history or current condition of any of these former HECP facilities, please contact us. Any photographs of the exterior, interior, or equipment would be of great interest to us.
Fort Burnside HECP
Photo: HECP - Fort Burnside, RI (From: Varoujan Karentz )

Sources and further reading:

United States Army in World War II, The Western Hemisphere, Guarding the United States and it's Outposts, Office of the Chief of Military History, Department of the Army.

Special History Study, Fort Moultrie HECP-HDCP, Edwin C. Bearss, National Park Service, May 1974.

The Fort Wadsworth HECP, US Navy, 1945(?)

Naval Harbor Defense, U.S. Navy, OPNAV 30-3A
Photo: Page from Naval Harbor Defense, U.S. Navy, OPNAV 30-3A

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