Reconnaissance of the Gilbert Islands
U.S.S NAUTILUS (SS 168) War Patrol #6
USS Nautilus full spead ahead.
Reconnaissance at Tarawa
9 October 1043
Early morning light conditions were unusual. The land could be seen at 20,000 yards. The sea was flat calm with the surface like a blue mirror. Dived south of northeast end of BUTARITARI Island and maintained a position to work the south beach running with the current. At 0709 M sighted a single float seaplane over tree line (Contact #9). By 0800 M the light was good. The sea was still absolutely flat. At 1016 M sighted a single float seaplane over tree line (Contact #10), distance 3000 yards. He turned toward us. Thought he saw us. Went to 90 feet for 20 minutes. Completed pictures of this beach at 1150 M. At 1154 M sighted a single float seaplane (Contact #11) over the lagoon. Retired westward.
10 October 1943
0045 M Sent dispatch 090900 indicating completion of mission. Patrolled area west of lagoon entrance to get a look inside and to intercept anything moving in or out. The islands here are reasonably well charted and may be navigated using the same north point used between UKIANGONG and FLINK Points, (7d counterclockwise from chart north).
1402 M Sighted ship. She was a small inter islet tanker, type not shown in ONI 208J. Attacked. (Attack #1). Missed ahead. A small escort with fast light screws came in from the southwest at high speed. He had sound gear and passed close aboard down the starboard side. Depth charge attack commenced at 1419 M. A total of eight depth charges and three aerial bombs were dropped in a period of an hour and twenty-five minutes. The aircraft bomb explosions were heard at 1510, 1535, and 1543 M. While these were heavy bombs they were not close. Evaded at deep submergence and retired eastward. Surfaced and changed course south at 1930 M. Noted for the first time we had a temperature gradient of about 4d between surface and 300 feet. Was surprised to see temperature return to zero gradient, same depth, after run of three hours. At 2325 M received orders to terminate patrol. Changed course to 070d T at full speed to get clear of the area.
11 October 1943
dived at dawn as we were lonely 25 miles from MAKIN, and remained submerged all day. 1830 M surfaced and set rhumb line course to Pearl at full speed.
12 October 1943
Made dawn dive, surfaced at sunrise. Changed zone description to +12 at midnight.
12 October to 17 October 1943
Enroute via rhumb line to Pearl.
0830 Y 13 October 1943 sent required dispatch requesting rendezvous. Made dawn dives. Had used cloud cover and many rain squalls until 14 October. Strong northeast trades commenced at Latitude 13d N. At 0032 Z 17 October sighted a submarine in Latitude 19d 47' N, Longitude 181d 24'W. Made report. Saw only the conning tower which looked like a new type U.S. submarine. 0235 Z 17 October received Comsubpac dispatch 170155 indicating submarine was enemy. At 0300 Z sent dispatch evaluating contact. At 0622 VW made rendezvous with escort and headed for Pearl.
The weather in the area was good to excellent conforming to that stated in Sailing directions. Clouds and rains interfered at MAKIN with picture taking. The sea was moderate for the most part. For two days at MAKIN it was perfectly flat and glassy. The weather during the trip to the area was good. Normal trades were blowing. The counter equatorial current was noticed between 10d N and 6d N. Much rain was encountered on the return trip from the area to 13d North latitude. Northeast trades were blowing from Latitude 10d North to Pearl.
3. TIDAL INFORMATION
The following facts will be of interest to any vessel subsequently working in the GILBERT Islands.
There is a very strong current in the region setting to the westward at 1.5 to 1.8 knots. As the whole Kingsmill Archipelago is a submerged mountain range of unknown shape, the general westerly set of the current is deflected in certain places.
At the MAKIN atoll the general set is along 315d T drift 1.8 knots. This current subsides at the eastern end of BUTARITARI Island. The set south of BUTARIOTARI Island is 2 knots which follows the contour of the reef. When this current again joins the general set it produces tide rips south of UKIANGONG Point. The set south of the eastern large island follows the reef and sets 070d T. east of MAKIN the set is northerly as the LITTLE MAKIN GROUP is arranged in that direction. The drift in this region is 2.0 knots. North of LITTLE MAKIN are more tide rips. In the region to the westward of MAKIN the currents are unpredictable. Tide rips are quite pronounced. The five feet rise and fall of tide which alternately fills and empties the lagoon mostly through the passes along the west reef introduced the factor which makes the currents unpredictable. Twenty miles west of MAKIN the current is back to a normal set of 316d T, drift 1.8 knots.
At the TARAWA Atoll the general set is 270d T, drift 1.6 knots. Along the east beach the current follows the reef line but is only about .3 knots 1800 yards off the reef. North of TARAWA the current sets 290d T at 2.4 knots caused by the combined deflection of TARAWA and APIANG. The current along the south coast 1800 yards off the reef is .5 knots and sets westerly parallel to the reef. 3 miles off the reef the drift is 1.8 knots; set 270d T. On the west side of TARAWA near BITITU the eddy effect is present plus the tidal current caused by the filling and emptying of the lagoon. A drift of .5 knots setting 000d T was encountered 3 miles northwest of BITITU. This western region is considered unpredictable.
At APAMAMA Atoll the general set is 260d T drift 16. Knots. The current divides at the southeast part of the island and follows the reef northward and southward. The current 1800 yards off the reef is .3 knots setting parallel to the reef on the east beach. Along the north beach the drift reached 2.0 knots. Eddy current exists on the Northwest beach. The set noted was south at 1.5 knots. Here again because of the tidal effect of the lagoon the currents have rips and are not predictable.
4. NAVIGATIONAL AIDS
The charts of TARAWA and APAMAMA were very accurate as to shape. The only error was in the north point. H.O. Charts also have this error. No statement can be make as their geographical location. They were located without difficulty. Rotate the north point 11d clockwise on TARAWA or rotate the island counter clockwise. Rotate APAMAMA 10d the other way, i.e., the north point counter clockwise or the island clockwise.
The charts of MAKIN available were the H.O. Chart NO. 119 and a blueprint chart used in the MAKIN raid in August 1942, with the following label: Makin, Sortie Army-s, July 23, 1943, prepared by P.R.I.S.I.C. Based on British Chart of MAKIN and U.S. Marine Corps notes.
The H.O. Chart was impossible. The blueprint was somewhat better, but defied close navigation. The western portion of the atoll may be navigated by rotating the north point 7d counter clockwise. The chart may be then used for other than close inshore work.
5. SHIP CONTACTS
6. TABULATION OF AIRCRAFT SIGHTED
7. FIRE CONTROL AND TORPEDO DATA
The misses were caused by incorrect speed estimate. The target was zigzagging and may possibly have slowed for some reason as she was nearing the lagoon entrance.
The target appeared to be a small tanker of about 1500 tons. Three torpedoes were fired using a divergent spread, at a range of 2000 yards. Using a target speed of 8 knots, the torpedoes missed ahead. Actually the target speed was about 5 knots. Target saw the torpedo wakes and turned toward NAUTILUS and at same time increased speed. Fired fourth torpedo down throat and missed. Maneuvered to evade depth charge attack.
8. ENEMY ANTISUBMARINE MEASURES
Depth charges were believed launched from throwers as the explosions were close together. Aircraft depth bombs were also believed used. These seemed to detonated shortly after the impact with the water and much rain was heard after the explosions. The noise sequence leads to the opinion that they were dropped by aircraft.
9. ENEMY MINING ACTIVITIES
No mines or mining activities were noted.
10. MAJOR DEFECTS
a. Machinery 1. 3 main engine cylinder liners cracked. This is a will known and chronic design defect. 2. The free wheeling ahead clutch of No. 1 main engine carried away. Decommissioned engine for 10 hours. Faulty design. Has occurred before.
b. Hull 1. No. 2 periscope turns hard in its bearings. It has numerous spots in the field. 2. No. 1 periscope has two spots in the field; one has the appearance of a ship; the other an airplane. 3. The secondary drain line developed a hole in that section which runs through the port forward stateroom. It was inaccessible for repair. 4. The ship will require reballasting; if her mission requires carrying a full load of torpedoes, t is mandatory that it be done at once. If not it may be postponed.
Radio reception was good except for occasional interference. The radio equipment performed in a satisfactory manner except as follows:
The underwater loop antenna worked for the first test dive in Pearl Harbor area but on second day of patrol it was found to be grounded. Resistance to ground read only 80,000 ohms. At end of patrol resistance was 9,000 ohms. We had no underwater reception.
The P.P.I. unit was installed temporarily for this mission. Its greatest range was 12,000 yards. The radar's operated satisfactorily whenever required, and except for the short range the P.P.I. installation was most satisfactory.
13. SOUND CONDITIONS AND DENSITY LAYERS
The sound gear functioned satisfactorily.
Sound conditions here stated apply to the area from the equator to 4d north latitude between 172d and 174d east longitude.
The temperature gradients were isothermal to 31o feet. On one occasion in Latitude 3d 34'N, Longitude 172d 40' E the temperature was 4d cooler at 300 feet but changed back to the ambient temperature as the ship drew farther from land.
Sound conditions in this area appear to be excellent for echo ranging or listening. Surf could be heard to 8000 yards. Listening conditions were better in the morning than in the afternoon. Subterranean pounding noises similar to those in the Aleutian area were heard which might be fish, or volcanic. The usual groans, creaks, and squeals of fish were unusually plentiful. These waters are apparently full of fish.
No density layers were noted in the area bounded by the equator and 4d North and 174d to 172d East Longitude, from September 23rd to October 12, 1943.
14. HEALTH AND HABITABILITY
The health of the crew was excellent.
The food was excellent and well prepared.
Living conditions were good. The air-conditioning is adequate for normal complement except in the conning tower.
There were only two minor accidental injuries.
The state of training was good. Every opportunity was taken to hod schools for additional training. Their performance of duty under combat conditions was excellent.
16. MILES STEAMED
Pearl to area 2100
In area 2250
Area to Pearl 2000
17. FUEL Expended
Pearl to area 36,225 gallons
In area 22,740 gallons
Area to Pearl 37,325 gallons
Days enroute to area 9
Days in area 18
Days enroute to Pearl 8
Days submerged 18
19. FACTORS OF ENDURANCE
FUEL 50,000 gal.; PROVISIONS 55 days; TORPEDOES 24; PERSONNEL 35 days
20. FACTORS WHICH ENDED PATROL
Limiting factor this patrol: terminated by order of Task Force Commander
The method used in photographing the beaches was to take a group of pictures at one time. One officer turned the periscope between each exposure. Another took the pictures. The average time to take a roll of twelve pictures was a little under two minutes. The time required could be shortened some by special equipment. The greatest cause of delay was spray on the lens, vibration, or rolling of the ship. Unfortunately No. 2 periscope, which was used because of its larger field, turned with great difficulty and was occasionally responsible for some delay between exposures.
The camera used was a single lens reflex type using size 120 super XX film divided into 12 exposures of 2 1/4" x 2 1/4" negative size. This camera had a 10 cm. F 4.8 Mayer trioplan lens. Shutter speeds of from 1/25th to 1/50th second were used depending upon the light.
The experimental pictures were taken using a speed graphic camera with a 4" x 5" cut film negative super XXX. This camera would be useless for this work as it would reveal vibration etc., as does a single lens reflex, but showed definitely that a larger negative size is superior to a small one including the increased grain of super XXX film over super XX.
If any further periscope reconnaissance missions are to be made it is suggested that much thought be given to the camera which must be fast of rewind, and must permit a view of the object to be photographed to prevent making an exposure while the periscope is fogged, vibrating, underwater, or not pointed properly due to rolling of the ship.
Enlarging was not satisfactory because of vibration.
Taking pictures of the P.P.I. screen was simplicity itself. The exposure is as long as the time for one revolution of the antenna. The persistent feature of the P.P.I. tube is not made use of as the film is really the persistent part. It is possible that a non-persistent chemical coating would give better results if a green electron beam produced more illumination. The normal scope detected palm trees to 17,000 yards the P.P.I. to only 12,000 yards.
This patrol report was transcribed from National Archives microfiche by Rod Rupert
Additional reports available at Rod's website:
copyright 1999 - 2001 Wheaton, Illinois
Created 22 August 1999 - Updated 14 January 2001