Chapter VII. Miscellaneous

From: Commander Amphibious Forces, United States Pacific Fleet (Commander Joint Expeditionary Force)

LSV AND LSD's

In addition to the heavy ships, one LSV and three LSD's, all of which were in the forward area, were assigned to the operation. The LSV was assigned to the Third Marine Division and loaded a medical company and 50 amphibious trailers loaded with rations, ammunition and water for emergency use ashore. It was intended that the LSV be employed primarily as a medical evacuation ship. The LSD's were originally intended to transport LCT's and LCM(3)'s loaded with medium tanks from Saipan to the objective. One lot of 18 tanks was to have been distributed among 3 LCT's and the other two lots of 18 tanks in LCM(3)'s. When it was found by tests conducted that the current model medium tank to be used in the operation exceeded the safe loading limit of the LCM(3) it was decided to use 6 LSM's to transport the 36 medium tanks which were to have been loaded in two of the LSD's. The two LSD's were required at the objective to provide small craft docking and repair facilities and accordingly were employed to transport the 36 LCM(3)'s each of which received a substitute load of naval resupply ammunition, 1 lot being loaded at Guam from shore stocks and the other at Saipan from 8 of the LST's carrying preload No. 3 comprising naval resupply ammunition.

LST's and LSM's

Sixty LST's and twenty-five LSM's were originally available for the operation. Subsequent to issuance of loading orders results of tests confirmed that the medium tanks being used were of greater weight than those previously used and too heavy to be transported in LCM(3)'s loaded in LSD's as intended. Accordingly, six additional LSM's were requested making the final allocation of LST's and LSM's as follows:

4thMarDiv: LST's LSM's
     LVT's 14 ---
     Halftracks and vehicles --- 3
     Medium tanks --- 10
     Shore party --- 3
     Artillery   5 ---
      19 16
     

5thMarDiv:    
     LVT's 14 ---
     Vehicles and shore party --- 6
     Medium tanks --- 6
     Artillery   5 ---
      19 12
     

5thPhibCorps:    
     Artillery 6 ---
     Shore party 3 3
     AAAW Bn 3 ---
     Vehicle loaded supplies 2 ---
     Construction Bn(naval) 2 ---
     Engineer Bn 2 ---
     3rdMarDiv tanks 2 ---
     AAA Bn   2 ---
      22 3
     

      60 31

LANDING CRAFT

LCM(3) AND LCV(P)

Landing boats were particularly ineffective during this operation due to the nature of the beaches. The slope at the water's edge was very steep, the black volcanic sand was soft, loose, and more nearly resembled a very light, fine cinder which would not pack, than a sand beach.

When boats were driven up hard onto the beach in an effort to provide a dry ramp and set the boat firmly on the sand, the stern was nearly submerged and in many cases boats were swamped by the surf which broke directly on the beach and into the boat. If the boat was not well beached, waves surging up the steep slope tended to flood the boat through the open ramp. Boats would not hold their positions in the soft sand and there were

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many broached boats. LCM's were less affected by the beach and surf conditions but both LCM(3) and LCV(P) were continuously in danger of swamping and broaching as long as they remained beached. Once broached, boats were speedily engulfed in the soft sand which made the salvage problem difficult.

As the operation progressed surf conditions became steadily worse; it soon became evident that LCV(P)'s could not negotiate the beaches and they were withdrawn from beach operation. LCM's were used in decreasing numbers until Love-plus-Five when their use was discontinued on eastern beaches. Although the slope of the western beaches as less abrupt than on the eastern beaches, the surf conditions good after unloading in this area began, there was still continuous danger of broaching and it was necessary to run engines in an effort to hold the boats on and give some measure of control.

Stern anchors were not used during the operation, and although they might have prevented broaching in some cases, their use is not recommended under similar circumstances as one of the major difficulties encountered in handling LST's and landing craft on these beaches came from fouled screws. Fouled screws frequently resulted in broaching unless a salvage vessel or boat was immediately available to handle the situation.

LVT's

LVT(A)'s led the assault and supported the landing by fire on the objective beaches. LVT's landed the assault troops as scheduled in the Landing Attack Order and were thereafter used in landing cargo. LVT(A)'s continued to support the assault by covering the flanks of the beaches, by close-in fire from the water against caves and other prepared positions close to the shore and by furnishing support to troop units holding lines extending to the water. No attempt was made to take them far inland or to use them as tanks due to their vulnerability when not waterborne.

LVT's were particularly useful in this operation due to the difficulties encountered in operating wheeled vehicles in the soft sand of the beaches. They were used in unloading from LST's during the early stages of the assault and moved their loads to inland dumps or to provide direct troop support.

Conditions were not favorable for LVT operation as there was at all times sufficient swell to make handling in and out of LST's a difficult matter. Sea and surf conditions were such that any overloading of LVT's was liable to result in swamping. They are not good heavy weather craft; when loaded, freeboard may be reduced to a point where more water is shipped than hand pumps can handle. In case of engine failure LVT's must be taken on board LST's or towed to the beach promptly otherwise, there is positive danger of sinking. Although the inadequacy of emergency hand operated pumps has been stated in every report of operations, no action to overcome this defect has yet been taken.

The operation of LVT's is primarily the responsibility of the LVT battalion officers. To better enable these officers to supervise LVT operation, provision has been made for their assignment ot control vessels stationed off the various beaches in order that they may exercise more direct control. When swells are heavy or the sea becomes rough, it may be impossible to reembark LVT's in LST's either for security, loading, or servicing. When LVT operations continue day and night it is necessary that LVT's know locations of the LST's which they are unloading. LVT's have limited visibility and indifferent sea keeping qualities. Although primary responsibility for LVT operation may rest with the battalion officers, commanding officers of LST's working with or servicing LVT's, control officers and beachmasters likewise have very definite responsibilities for the continued and effective operation of LVT's as follows:

LST COMMANDING OFFICERS

Advise the control officer, and through him the beachmaster of the beach off which he is operating, whenever he is required to leave his assigned station or is unable to maintain it.

Advise officers directing LVT operations if, for any reason, he is unable to take LVT's on board either for salvage, servicing, or unloading.

An LST commanding officer shall assist any LVT which is in trouble to the best of his ability. If he is unable to take the LVT on board for repairs and service, he shall immediately advise the control officer of the nearest beach or himself take steps for its salvage.

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DUKW'S

Difficulty was likewise experienced in handling DUKW's on the soft sand beaches. DUKW tires, even when deflated, had a tendency to dig into the sand causing the DUKW to belly. It was usually necessary to tow them clear of the beach, using tractors, until beach matting had been laid or ramps built to the water's edge. On occasion, experienced drivers were unable to negotiate the beaches by putting the vehicle in low gear, deflating tires, and making a slow approach. Many DUKW's were broached; however, a large percentage of them were later salvaged.

As sea and surf conditions became worse, the operation of DUKW's became increasingly difficult. As in the case of LVT's, it is not possible to embark DUKW's in a rough sea with a heavy swell. If the DUKW is loaded, the difficulties of embarkation are increased. In many instances DUKW's were loaded and sent to the beach when surf conditions were such that DUKW's could not land without serious danger of swamping and broaching. Their recovery by the parent LST was also impracticable. The result was that a number of loaded DUKW's which could neither land nor be reembarked were held off the beaches. As in the case of the LVT, hand pumps were inadequate. The result was that DUKW's which had engine failures or which ran out of gas and were not promptly refueled, sank off the beaches. There was a general tendency to overload these vehicles based on theoretical capacities. A safe load for a DUKW under average operating conditions is about 5,000 pounds, the normal load of an LCVP. Operating conditions off Iwo Jima were not good; however, many DUKW's were loaded with cargo in excess of 7,000 pounds in spite of DUKW company officers' recommendations to the contrary. These craft usually were the first to swamp, thus losing both vehicle and load.

Many of the remarks which have been made in connection with the operation of LVT's are equally applicable to the operation of DUKW's. The officers of the DUKW companies should exercise close control over their vehicles. LST's assigned to servicing DUKW's and which are being unloaded by DUKW's must keep the officers of the DUKW companies informed as to their movements and their ability to recover vehicles. The launching of DUKW's should be controlled by an officer who knows their capabilities; they should not be launched if they cannot land. LST commanding officers, control officers, and beachmasters have responsibilities for DUKW operation similar to those with which they are charged for LVT operation.

In future operations DUKW company officers should ride the control vessels stationed off the beaches to which DUKW's are unloading. It is necessary that all available information be passed to those officers, both afloat and ashore, who are responsible for the successful employment of these vehicles in unloading.

WEASELS

The Weasel is only semiamphibious; its low freeboard and resulting light load capacity would prevent it from being used as a ship-to-shore cargo carrier under any but ideal conditions. However, it is able to negotiate almost any kind of terrain and can carry loads up to about 500 pounds. It is believed that there are distinct possibilities for the employment of this vehicle over flat coral reefs in shallow water where swamping is unlikely and its speed, maneuverability, and ability to surmount abrupt slopes may make it invaluable, although its primary function may not be that of hauling cargo. Conditions may be readily visualized under which it will be the only satisfactory vehicle available for unloading.

From: Commanding General Expeditionary Troops (CTF-56)

The value of this vehicle (Weasel) cannot be overemphasized. During the early phases of the assault, they were used extensively and proved invaluable in supplying front line troops with medical supplies and ammunition.

From: Commander Amphibious Forces, United States Pacific Fleet (Commander Joint Expeditionary Force)

BARGES AND CAUSEWAYS

The steep beaches and heavy surf made it impossible to use the barges for unloading purposes. The only barges which were satisfactorily employed as intended were those used in connection

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with the casualty evacuation LST's. These barges, four in number, were moored alongside the LST's, and since they rose and fell with the sea together with the small craft carrying casualties from the beach, enabled quick unloading of the small craft and rapid transfer of casualties to the LST's. It is estimated that many lives were saved due to the rapid transfer of casualties effected by the use of barges.

The nature of the beach and surf made construction of piers and causeways impracticable. Attempts to construct piers only resulted in the pontoon sections broaching on the beach, damaging other craft and obstructing the beach. The only useful accomplishment of the causeways was the construction of a 4 by 30 fuel barge from causeways carried on LST 761. This was anchored off YELLOW 1 and in use throughout the assault.

LST(M)

The Iwo Jima operation marked the first appearance of a new type of logistic vessel, the LST Landing Craft Tender, familiarly known as the "mother ship." Of the four LST's converted to LST(M)'s as a result of experience gained in the Marianas campaign, two took part in the Iwo Jima operation. They were constructed with 20 "reefer" boxes in the tank deck for carrying 160,000 rations of fresh and frozen provisions, stowage space for 160,000 rations of dry provisions, bunks for 350 additional enlisted men in the tank deck, bunks for 40 officers in a quonset hut on the main deck, and extra galley also housed in a main deck quonset hut, additional washroom facilities, and large evaporators. These ships were designed to act both as a "home" for transients and boat crews left behind at the objective upon nightly retirement of transports, and as supply ships for small craft ranging from PCEs through LCTs.

In this function they were eminently successful, berthing a total of over 2,500 officers and men, subsisting 4,900 officers and men, refueling and watering 54 vessels and reprovisioning 76 vessels, all between D-day and D-plus-15. Their value should be even greater during a longer operation, where the prospect of a hot meal, a shower and a good night's sleep for "stray" boat crews, and fresh provisions for the small craft, will doubtless serve as an excellent morale builder.

From: Commander Task Group 53.4 (Commander LSM Flotilla 5)

Damage from loading alongside transports constituted an estimated 93 percent of all damage sustained. As a whole it may be classed as serious, and for the most part unavoidable, since not only bad or poor weather contributed to the damage, but also the inherent design features of all LSM's lead to the inevitable damaging of every pot side of every vessel including title A, B, and C equipment there installed. Again it is pointed out that this is a general report; consequently, the following information is in no way specific but presented only as an over-all picture of damage incurred while alongside transports loading.

In future operations APA's and AKA's must provide suitable fenders to prevent damage to themselves and LSM's while alongside. Fenders should be at least 15 feet in length, made of telephone poles lashed three together to distribute the pressure over a large area.

LIFE SAVING DEVICES

From: Commander Task Group 58.2 (Commander Carrier Division 2)

An excellent measure adopted by Franklin was that of securing metal Jacob's ladders at various points around the elevated parts of the ship including the island structure. The top of these ladders were shackled into welded eyes. Manila life lines are not satisfactory because they burn away and are too difficult to ascend and descend.

The kapok life jacket proved superior to the pneumatic lifebelt in two important respects. First it provides splinter protection to the man who wears it, and, second, it give better support in the water. Topside personnel should be required to wear life jackets at all times when air attack is probable. Many personnel who were not wearing life jackets were blown over the side from Franklin. Additional spare life jackets should be stowed in quantity on the forecastle and stern, the two most probable gathering places for personnel prior to abandoning ship.

Life jackets fitted with slabs of Doron, a fibrous spun glass material 1/8-inch thick, are being issued to the amphibious forces. This body armor, weighing 8 pounds, will stop a .45-caliber bullet and a high percentage of fragments. It covers a

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man's trunk and abdomen and thus protects those parts where most of the fatal wounds occur. To date 300,000 life jackets so fitted have been sent to the operating areas.

SMOKE

From: Commander Amphibious Group Two (CTF 53 and CTG 51.21)

Smoke again proved to be invaluable as protective cover for ships in the transport area against detection by enemy planes during night air raids. Enemy planes flew over the smoke hidden ships apparently unable to take any effective action. Smoke was used 16 times for a total of 9 hours and 47 minutes. During these raids no ships in the smoke screen were hit by bombs. The U.S.S. Auburn (AGC 10), completely covered with smoke, was straddled by five bombs with the closest one landing approximately 300 yards away. Smoke was not used in the daytime to cover transports.

Very little difficulty was encountered with the operation of the portable oil fog generators. Their performance throughout the operation was most satisfying. These generators are capable of emitting large volumes of nontoxic smoke that persists for long distances downwind. No trouble was encountered by Floating Smoke Pots M4A2 and Mk3 pots igniting spontaneously. The floating smoke pots are invaluable for establishing a quick screen and maintaining it at the source.

From: Commander Amphibious Forces, United States Pacific Fleet (Commander Joint Expeditionary Force)

The plan for covering the transport area with smoke during air attacks consisted basically of stationing LCI type vessels and other small craft equipped with Besler (or Todd) fog generators in a line across the windward side of the transport area. In addition, each transport in the area stationed two LCVP's, equipped with light weight fog generator (or smoke pots) and smoke floats to windward of the parent vessel. The transports also made smoke, utilizing fog generators installed on board.

Ships and boats were ordered to commence smoking when "bogeys" were observed on the radar screen in such a position and on such a course that an air attack seemed likely. The use of smoke more or less paralleled "Flash Red."

While at Saipan en route to Iwo Jima the Transport Area Smoke Plan was executed during the afternoon to test its effectiveness during daylight. The conclusion was that the advantages obtained form smoke during daylight air attacks are outweighted by the disadvantage of reducing effectiveness of gunfire.

From: Commanding Officer U.S.S. "Salt Lake City" (CA)

FS[*] smoke is decidedly irritating to the respiratory system, and should not be used in any position where the wind blows it over the gun stations. It completely ruins the efficiency of the gun crews. One gun crew thus exposed during an enemy air raid was sent to the sickbay for examination and four had enough respiratory disturbance to require absolute rest for 24 hours. All of this group were required to bathe immediately using considerable soap and water to relive the burning sensation experienced in the exposed skin. It is believed a sulfurous acid is formed on contact with moist surfaces. Evidences of its activity on bits and shields about the stern were also noted.

GROUND WEAPONS

From: Commanding General, Headquarters Fourth Marine Division, Fleet Marine Force

Comment.--Experience gained in the Iwo Jima operation emphasized the need for a heavier and more powerful direct fire weapon than the Bazooka for use of assault teams against concrete emplacements and caves, employing a shell with concrete-piercing capabilities against the former and a fragmentation shell for attack of the latter.

Recommendation.--that a short range rocket of 4.5" caliber, capable of being crew served by two men of the assault team and firing concrete-piercing and fragmentation ammunition, be adopted.

Comment.--The need for additional mortars in the division, particularly a heavier type mortar than the 81-mm., was apparent in the operation. Heavier mortars should be employed to supplement


[* "FS" = Sulphur Trioxide in Chlorosulforic Acid.]

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the organic 81-mm. mortar platoons and provide the infantry commander with vitally needed additional fire support to bridge the gap between the 81 mm. and artillery.

Recommendation.--That the 4".2 mortar be adopted by the Marine Corps and a mortar battalion of two 4".2 companies and one 155-mm. mortar company be assigned to each division.

 

Captured 155-mm. Mortar With Bipod Attached.
Captured 155-mm. Mortar With Bipod Attached.


Rugged Terrain in the Northern Part of the Island Made Progress Difficult and Casualties High.

Entrance to Japanese 81-mm. Mortar Ammunition Dump.
Entrance to Japanese 81-mm. Mortar Ammunition Dump.

Rugged Terrain in the Northern Part of the Island Made Progress Difficult and Casualties High.
Rugged Terrain in the Northern Part of the Island Made Progress Difficult and Casualties High.

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