Naval History and Heritage Command

The Eldorado reports:

Prior to the Iwo Jima Operation Combat Information Center had been afforded numerous training exercises which started immediately after the commissioning of the ship on the East Coast and continued until its arrival at Pearl Harbor three months later. Nearly all of these exercises, however, were performed within the CIC itself and only on a few occasions was it possible to conduct exercises with the Combat Information Centers of other ships or actually control aircraft.

After arrival at Pearl Harbor in late November 1944 there were training periods off Oahu during which this CIC had extensive practice in working with the other ships of the disposition and in controlling aircraft. This training proved most beneficial in that it not only trained the personnel of the CIC, but also made clear for the first time what would be expected from CIC. Through the close cooperation of the Force Fighter Director and CIC officers the function of CIC was determined and the organization and physical equipment were changed to best produce the results required.

The following is a summary of several of the changes made in CIC prior to this operation which subsequently proved most beneficial:

(1) Upon arrival at Pearl Harbor the Officer personnel of CIC consisted of nine Fighter Directors Officers trained at NRTS [Navy Radar Training School], St. Simons Island, Georgia. Due to the need of Fighter Director Officers elsewhere and the fact this vessel did not have any Officers specially trained in Radar Navigation aboard, two of the Fighter Director Officers of the Eldorado were transferred to other Fighter Director ships and two

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Officers trained at the Radar School at Hollywood, Florida, were transferred to this ship. The special training these Officers had received in Radar Navigation considerably improved the value and amount of surface information produced by CIC. Upon approaching Saipan the weather was so bad that Navigation by Radar was used exclusively and found most satisfactory. The SP [Air and surface search] radar is a great asset to navigation due to its long range on land and surface targets.

Briefing sessions of the off duty section of CIC were held during morning General Quarters and on some afternoons each day while enroute to the objective. These sessions insured that both officers and men knew the details of the operation plan and were familiar with other pertinent publications. They also provided a forum for solution of problems of a general nature which came up during watches. The CIC personnel consists of nine officers and forty men. The battle bill was rearranged so that there were two complete and separate teams, the port and starboard General Quarters sections consisting of four officers and twenty men each, the ninth officer acting as Visual Fighter Director Officer. In each of these sections the senior officer was responsible for and in charge of his General Quarters section and acted as Evaluator. In addition in each General Quarters section there was intercept officer, a Surface Navigation Officer, and a Radar Control Officer. The condition watches were arranged on a four section basis. It was possible to switch form a condition to a General Quarters watch or back without causing officers or men to stand more than their share of the watch. This type organization proved highly satisfactory for extended cruising and long periods of time at the objective.

Through the cooperation of the Force Fighter Director nine interior illuminated Lucite status boards were obtained from the Navy Yard at Pearl Harbor. These boards utilize all bulkhead space available in CIC for displaying information and have more than any other one factor reduced the “wait” in passing information from CIC. The Lucite is not engraved in the usual manner and it was found best to place the desired forms on the back of the Lucite with China-marking pencils, thus enabling change of the forms as conditions required. During this operation these boards were used in the following manner:

1. One large board as the Air Status Board;

2. One medium size board as an alphabetical display of the call names of all ships in the vicinity which might be of interest;

3. One small board to the right of the main display board for weather and Radar Picket stations;

4. One medium size board to the left of the main display board for Raids and Radar Control information;

5. One large board for surface recording, zigzag plan, and base course;

6. Two large boards near the DRT [Dead reckoning tracer] for plotting expected friendly contacts, general surface information, and submarine contacts (charts are placed on the back of the board and are seen through the Lucite);

7. One radio circuit board near the radio monitors with all frequencies and the radio positions in CIC displayed thereon

8. One board on the ship's bridge for the JS talker there to display information received from CIC. This board was equipped with weak red lights in order that it might be used at night without harming the night vision of the bridge personnel or being visible outside the ship. In addition to the Lucite boards CIC personnel constructed a large Plexiglass chart board which was mounted near the DRT and used for surface navigation.

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Chronological Summary

During the Iwo Jima Operation CIC on the Eldorado was operated on a watch-and-watch basis commencing at 0400 on D Day. However, a relatively small percentage of the time spent at the objective was taken up with the tracking of “bogies” and “friendlies” on actual intercept flights. The average day-to-day routine in CIC may be broken down as follows, with little real variance being noted:

1. Tracking of the Anti-Submarine Patrols over the various legs of their assigned sectors to assist CASCU [Commander aircraft support control unit] in the task of keeping track of these flights, and as part of the general CIC policy to keep track of all friendly aircraft in the area. On more than one occasion lost ASP [Anti-submarine patrol] planes were “homed” by CASCU on information available from CIC. Likewise planes off-sector were guided back on in similar fashion. The tracking of the night ASP flights was notably successful, with the possible exception of the sector to the northwest which was partially blocked by Iwo Jima itself. Tracking of the more complex day sectors was somewhat less successful, but satisfactory.

2. Tracking of “strikes” northbound to Tokyo, Chichi and Iwo Jima. B-29 and B-24 flights to the Empire and to the Bonins were consistently picked up at well over 100 miles to the south and tracked northward to an equal distance. On their return particular attention was paid to possible indications of emergency IFF [Indication friend or foe (radar)] as the B-29 flights came by at scattered intervals. The B-24 strikes on Chichi became a routine evening occurrence from 2000 (K) on. Accurate tracks, with courses, speeds and “angels” were kept on the Vertical Plot with all other flights.

3. A constant watch and visual record was maintained on all airborne Combat Air Patrols working in the area, those actually assigned to the objective, and those guarding the carrier groups at a greater distance.

4. All special flights-weather — press and photographic — were tracked into the objective, and away from the area to assist CASCU and any other interested agencies in giving directions to the pilots.

5. Combat Air Patrols of FM-2’s and F6F’s (later P51’s and P61’s) from the carrier groups reported initially to “Delegate Base” (Eldorado) and were assigned to various Fighter Director destroyers or to the Auburn for control. The patrols varied in numbers from three divisions to six. Eldorado control, due to the heavy volume of traffic passing through CIC, was limited almost entirely to the VF (N)’s.

6. Weather permitting, VF (N)’s reported each night from the carriers and were stationed in the area immediately north of Iwo Jima. For the most part, control was exercised by the Eldorado because of the SP radar. Successful navigational fixes were obtained at regular intervals from the SG [Surface search radar] radars. The various retirement groups were tracked away from the area at night and back in again in the early morning by the SP [Summary plotter (radar)] and SG’s [Surface search radar]. Good results were also obtained in the tracking of low-flying aircraft on both of the surface search sets.

7. All appropriate radio channels were continuously monitored—i.e., Inter-Fighter Director Primary and Secondary. Fighter Director Primary and Secondary, TBS [Talk Between Ships], and such other auxiliary circuits as from time to time became essential. Information was disseminated and received in considerable volume over the IFD [Inter-fighter director] nets without noticeable jamming of the frequencies. Contact reports received over these nets were recorded on the Vertical Plot in CIC.

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DAY FIGHTER DIRECTION

Due to the fact that the Force Fighter Director was located in the USS Eldorado CIC, Fighter Direction on this ship was primarily concerned with identification of all aircraft in the vicinity of Iwo Jima. The primary responsibility of the Intercept Officer during daylight hours was to keep track of all combat air patrol aircraft. This was accomplished by his maintaining close supervision of the air status board and keeping the position of the planes tracked on a remote PPI [Plan position indicator (radar scope). The average number of planes in the day-light CAP [Combat air patrol] ranged from sixteen to twenty-four on station for an interval of approximately one and one-half hours. These planes were launched by nearby CVE’s and reported to the Eldorado for assignment. The Intercept Officer assigned the divisions of the CAP to the Fighter Director Ships in the screen and to outlying Radar Pickets at stations and at altitudes desired by the Force Fighter Director. Pursuant to the policy of the Force Fighter Director no daylight interceptions were planned to be controlled from this ship, but the Intercept Officer was prepared to take over this function in the event that it could not be performed by the Fighter Director ships because of failure of communications or any other reason. Planes of the CAP which became lost in bad weather were “homed” by the fighter direction team of this ship.

Upon completion of duty on combat air patrol the retiring CAP was made available to CASCU for short missions before returning to their base. As CASCU is located adjacent to CIC on the Eldorado and other AGC’s it was possible to determine before the CAP was relieved whether planes were desired for missions or not.

Identification of all aircraft in this area was facilitated materially by close cooperation with CASCU. All planes on the anti-submarine patrol were controlled by an officer of CASCU who made frequent checks on their location on the Main Display board of CIC; and when any of these planes failed to show proper identification signals he issued instructions to the plane in question. By displaying in CIC expected friendly air contacts, including special flights, and by coordinating the radar reports of all Fighter Director Ships of the task force, CIC was able to identify successfully all friendly aircraft in the vicinity of Iwo Jima. Consequently there were only two false alerts, and these were caused by ships other than fighter director ships reporting a skunk or bogey over TBS [Radio transceiver (VHF). Likewise on the occasion of real raids, CIC was able to evaluate them as such and the task force was alerted in sufficient time to take proper defensive measures.

NIGHT FIGHER DIRECTION

For the first time in any amphibious operation an AGC was equipped for night fighter direction for the assault on Iwo Jima. In solving problems of operations and equipment, much was learned for future operations.

From the night of D-Day until the ship departed from the objective, a night combat air patrol of two night fighters was maintained for the protection of the force and the objective. On the last night, during which a raid occurred, shore based Army P-61 night fighters were used. An additional dusk CAP patrolled each night from 1730 until 1900. This CAP varied in number from eight to twelve. On two occasions weather forced the pancaking of the night CAP planes for several hours.

The night fighter planes were used to investigate various surface contacts, were placed in position to investigate planes which were not identifying themselves or were showing questionable identification, and to combat each raid upon the objective area.

In opposing enemy raids, there were no “kills” although numerous contacts were made on enemy planes which evaded the fighters by violent course and altitude changes. On one occasion the night fighter was about to open fire on a “Helen” after a visual identification at a range of 1000 feet when the “Helen” eluded the pilot by a violent maneuver. Several times night fighters were broken off contacts when they approached the effective range of our anti-aircraft fire.

It is considered very probable that the enemy planes were aware of the night fighters and were consequently hurried in the attacks and unwilling to make steady bombing runs. It is believed that the night fighters harassed the enemy to the extent that he was unable to spend any time outside of AA range in picking targets and planning attacks on them.

The night fighter pilots from the Saratoga and Enterprise were most cooperative and performed most capably. Not a single night fighter plane or pilot from these carriers was lost at the objective due to enemy action, our anti-aircraft fire, or navigational errors, even though control of these planes was constantly shifted from their own base to other ships at the objective.

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AUBURN USED TWO WATCH BILLS

The Auburn employed two watch bills, one for cruising and one for the objective. They seem to be somewhat different from the set-up used by the Eldorado apparently had only 20 enlisted men on watch at General Quarters, while the Auburn had 29. This may be due to the fact that the radiomen used on nets guarded by CIC were considered a part of CIC complement on the Auburn while on other ships they may be borrowed from Air Support teams or from the ship’s communications complement.

THE AUBURN'S UNDERWAY WATCH BILL

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