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Mindoro

Relief map of Mindoro

Mindoro is located south of Luzon in the Philippine Islands. It is the seventh largest island in the archipelago, 110 miles (177km) long and 58 miles (93 km) across with an area of 3794 square miles (9826 km2). It is dominated by a forested mountain range reaching to 8481' (2585 m) at Mount Halcon in the north, with scrub-covered coastal plains to the east and southwest.

The chief city and port is San Jose, where Ilin Island shelters a small anchorage. However, the island was poorly developed in 1941, with only a rudimentary road network. The only improved road ran along the east coast while there was a short railroad running northwest from San Jose. The total population was about 117,000 persons.

The Mindoro Campaign. On 13 October 1944, MacArthur issued orders for the invasion of Mindoro on 5 December 1944. This operation would provide the Allies with airfields from which to cover landings at Lingayen Gulf on Luzon two weeks later. However, delays in constructing airfields on Leyte meant that the Allies were unable to wrest complete control of the air over the Philippines from the Japanese, and this together with significant shipping losses from kamikaze attacks forced MacArthur to postpone the Mindoro invasion to 15 December and the Luzon invasion to 9 January 1945. Six escort carriers were also assigned to the Mindoro invasion force to provide additional air cover. Even so, the operation was risky and daring, representing a leap of 260 miles (420 km) into restricted waters surrounded by enemy airfields. 

The invasion was carried out by Visayan Attack Force (Struble), which was divided into a Mindoro Attack Group of transports, landing ships and landing craft escorted by light cruiser Nashville and twelve destroyers; a Close Covering Group (Berkey) of two light cruisers, one heavy cruiser, and seven destroyers; and a Motor Torpedo Boat Group of 23 PT boats. Distant cover was provided by Ruddock's Heavy Cover and Carrier Group with six escort carriers, three battleships, and a strong screen operating in the Sibuyan Sea to the south. 5 Air Force provided what cover it could from its inadequate forward airfields, but was further hindered by poor weather over Leyte.

The Japanese defenses were very weak, consisting of perhaps 500 troops on Mindoro, of whom only 200 were concentrated around San Jose.

The first elements of the invasion force sortied on 12 December. The Mindoro Attack Force was protected by 12 fighters from the escort carriers and 35 Corsairs of MAG-12. The convoy was detected by Japanese reconnaissance aircraft at 0900 and came under attack starting at 1500, when a Val carrying two bombs crashed into Nashville and badly damaged her, with casualties of 133 dead and 190 wounded. Those killed included both Struble's and Dunckel's chiefs of staff, and Dunckel himself was wounded. Nashville retired to Leyte Gulf accompanied by a destroyer. A second wave of attackers, consisting of seven kamikazes escorted by three fighters, attacked the Heavy Cover and Carrier Group at 1705. Three broke through the combat air patrol and one of these hit Haraden, killing 14, wounding 24 and forcing her to return to Leyte Gulf. A third attack on Slow Tow Convoy scored no hits.

14 December was marked by an all-out effort by Japanese aircraft to destroy the invasion force. At least 186 aircraft were mustered for the attack, but most of these failed to locate the Americans and suffered heavy casualties, with at least 46 aircraft shot down. Most of the Japanese airfields were swept by fighters from Task Force 38 operating east of Luzon and were unable to put aircraft in the air. That night the convoys were protected by "Black Cats" scouting ahead of the invasion force. The minecraft swept the area around San Jose before dawn but found no mines.

Elements of 6 Army began landing on 15 December 1944, quickly overcame the weak Japanese resistance, and controlled San Jose and its airfield by noon. Engineers began construction of airbases, which were to be ready within two weeks. 

Though opposition on the ground was feeble, the Japanese responded strongly in the air. At 0812 on 15 December 1944 a group of 15 to 18 kamikazes with roughly an equal number of fighter escorts attacked the invasion force. Half headed for the escort carriers; all were shot down or missed their targets, with Marcus Island suffering one sailor killed from a glancing hit that did superficial damage. The other half attacked the amphibious force, setting LST-472 and LST-738 ablaze. Both were scuttled that evening. Japanese aircraft continued to attack almost every day between 16 and 24 December, with particularly heavy attacks on 20 and 21 December. The 20 December raid was a conventional attack by 29 aircraft against newly-operational Hill Field. Eleven Japanese planes were shot down at the cost of 3 P-47s.  The 21 December raid struck a resupply convoy approaching Mindoro and sank LST-460 and LST-749 and damaged Juan de Fuca.

The Japanese responded by sea. On 24 December 1944 a cruiser-destroyer force under Kimura Masatome (Penetration Force) sortied from Camranh Bay. This force was probably meant to be joined by fleet carrier Unryu, but she was sunk by Redfish on 19 December off Formosa. The operation went forward anyway, and foul weather prevented the Americans from sighting Penetration Force until 1600 December, when it had closed to within 200 miles of San Jose. 5 Air Force sortied every available aircraft against the Japanese, and a powerful cruiser-destroyer group sortied from Leyte Gulf under Ted Chandler in a desperate bid to intercept. Despite harassment by the Allied aircraft and PT boats, Kimura penetrated the American defenses, bombarded the beachhead for over twenty minutes, and got away with the loss of a single destroyer. However, the air attacks were sufficiently distracting to prevent the Japanese from bombarding accurately enough to do any serious damage, and almost all the Japanese ships suffered some damage.

On 28-31 December 1945 the Japanese heavily attacked a large reinforcement convoy ("Uncle Plus Fifteen") of 22 LSTs, 23 LCIs, 30 PTs, three Liberty Ships, a gasoline tanker, PT tender Orestes, two aircraft tenders, five Army cargo ships, and three smaller boats carrying 21 Regimental Combat Team and screened by nine destroyers. The convoy was attacked almost continually throughout its passage from Leyte. On 2012 28 December a group of six kamikazes hit William Sharon and John Burke. Burke was carrying munitions and disappeared in a thunderous explosion, while Sharon was crippled and had to be towed back to Leyte. At 1830, a group of 20 to 30 kamikazes crippled LST-750, which was scuttled. The next day a heavy combat air patrol prevented any attackers from breaking through, but late on 30 December, as the ships were unloading at San Jose, a group of Vals hit destroyers Gansevoort and Pringle, tender Orestes, and tanker Porcupine. Two hours later another group of aircraft sank Hobart Baker with a conventional bombing attack. Porcupine began to burn heavily at the stern, and in desperation the Americans attempted to torpedo her stern to put out the flames before they reached her cargo, but the attempt failed and Porcupine burned to the water line. 

On 31 December the Japanese heavily damaged Simeon G. Reed and Juan de Fuca. On the night of 1 January 1945 John Clayton was crippled, and on 4 January Lewis L. Dyche was hit while carrying a load of munitions and exploded with the loss of all hands. Thereafter Japanese attention shifted to the invasion convoy headed to Lingayen Gulf. Woodruff, who relieved the wounded Dunckel on 1 January 1945, did not attempt to secure the whole of Mindoro, but simply set up a perimeter against Japanese infantry raids, duplicating the tactics used at Bougainville.

The Mindoro campaign was costly, with 334 air raid alerts in the first 30 days. Postwar calculations from Japanese sources indicate that about 200 kamikazes were expended during the campaign. However, the airfields at San Jose provided badly needed air cover for the Lingayen Gulf landings, and San Jose became an important staging base for operations in the southern Philippines.

Allied order of battle, 11 December 1944

7 Fleet (Kinkaid)

  
Visayan Attack Force (Struble)


  
Mindoro Attack Force (Struble)        Carrying 1 regimental combat team of 24 Division and 503 Parachute Regiment (totaling 11,878 combat troops) and 9578 Air Force and 5901 service troops under William C. Dunckel.


 
CL Nashville Moderately damaged



DD Dashiell




11 other DD
1 damaged



8 APD




30 LST
2 sunk



12 LSM




31 LCI




17 minesweepers




14 other small craft



Close Covering Group (Berkey)     




1 CA




2 CL




7 DD



Motor Torpedo Boat Group




23 PT


Slow Tow Convoy



3 DD



2 DE



6 AT



1 AOG



2 LCT


Heavy Covering and Carrier Group (Ruddock)     



BB West Virgina



BB Colorado



BB New Mexico



CL Denver



CL Montpelier


CL Columbia


CVE Natoma Bay
24 fighters, 9 torpedo bombers


Taffy 2 (Stump)




CVE Manila Bay 24 fighters, 9 torpedo bombers



CVE Marcus Island 24 fighters, 9 torpedo bombers. Slightly damaged.



CVE Kadashan Bay 24 fighters, 9 torpedo bombers



CVE Savo Island 24 fighters, 9 torpedo bombers



CVE Ommaney Bay 24 fighters, 9 torpedo bombers


DD Haraden Moderately damaged


17 other DD of DesRon 22 and DesRon 54


5 Air Force (Kenney)
Effectiveness reduced by weather and poor airfields

MAG-12
Effectiveness reduced by weather and poor airfields

Japanese order of battle, 11 December 1944

14 Area Army (Yamashita)     

  
Mindoro Garrison
Approximately 500 troops, of which 200 were in the San Jose area

4 Air Army (Tominaga) About 100 aircraft
Southwest Area Fleet (Okawachi)      

2 Air Fleet (Fukudome) About 170 aircraft

Penetration Force (Kimura; at Camranh Bay)     



DD Kasumi



CA Ashigara



CL Oyodo



DD Kiyoshimo
Sunk


DD Asashimo


DD Kaya



DD Sugi


DD Kashi

References

Hastings (2007)

Morison (1959)

Rottman (2002)



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