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Ship Ahoy!


The WW2 Signal Corps Grand Fleet In The Pacific Theater

Continued from the September 2012 Home Page. To go to an archived version of that page, click here: September 2012 Home Page Archive. To return to this month's actual Home Page, click on the Signal Corps orange Home Page menu item in the upper left corner of this page.


Thus MacArthur and his staff arrived in Australia in early 1942, with no army and the task of preparing to attack Japan and obtain unconditional surrender. At the time Japan was threatening Australia. She had established an air strip on the island of Guadalcanal in order to block American equipment and troops coming to Australia. Her navy was threatening Australia from the Coral Sea near Australia. Landings had already been made on the Australian continent by the Japanese.

The strategy was to be one of island hopping. The Navy under Admiral Nimitz would move across the central Pacific. General MacArthur would island hop from Australia to the Philippines to Japan. Thus there would be a pincers movement.

General Akin studied the communications that would be necessary. The communications ships would have to serve the function of a forward command post. Also communications would be required from the command ships to the units on shore; broadcasting would be necessary for the civilian population and guerillas so they would know what was going on and help where possible. Communications between ships would be required. The press would have to be accommodated so the American people could be informed using the long distant transmitters. Above all secure communications would be necessary between the commanders and the Pentagon. The latter requirement meant that the only secure telephone system, SIGSALY, would have to be used. Obviously the only way to achieve these requirements was by creating a mobile seaborne fleet.   

General Akin had some early experiences using naval ships for communications. The value and usefulness of seaborne communications had been shown but there were problems of coordination with the navy and the applications being used by the ships. They often were only used as relay ships for ground communications systems. The mission of the Seaborne Communications Branch would have to be to provide command communications during an assault phase, to continue providing them while ground facilitates were setup, and to stand by for emergency communications. Early ships that served that purpose were the Harold and the Argosy. Later a more suitable ship, the FP-47, was acquired in Australia.

 Signal Corps WWII Fleet FP-47

From the expertise gained from his earlier experiences, General Akin had requested from the Navy three ships outfitted specifically for use as Army communications ships, He specified that the ships have sufficient armament to protect them against enemy attacks by sea or air. They would be armed with 40 and 20 millimeter antiaircraft guns, machine guns, depth charges and a three inch gun. This task force arrived off Red Beach, Leyte Gulf on October 21, 1944. The news of the invasion was broadcast to the world from the Apache and the FP-47. General MacArthur’s famous “I have returned” speech was broadcast to the Philippine people from the Nashville and to the people of the United States from the Apache. Japanese bombers searched out American communications installations and both the PCE-848 and PCE-850 were bombed and suffered casualties; one Signal Corps man was killed and two were wounded. The PCE-849 narrowly escaped while Signal Corps men manned 50 caliber machine guns.  

These ships equipped with high powered Australian transmitters and receivers that could reach the Pacific network as well as numerous other transmitters and receivers for tactical use were used for the Leyte invasion. The Apache was a vessel that had been scrapped and turned over to the Army for use as a news correspondents radio ship to send news via teletype and voice to the United States via a ten kilowatt transmitter on board. Five ship of the flotilla served the communications and intelligence functions required for the Leyte campaign. General MacArthur was on the USS Nashville; General Aikin was on the PCE-848. Aikin’s Navy included these five ships. AN/TRC-1 VHF radio sets provided communications between ships and to units on shore.

Also planned for the Grand Fleet was a mobile seaborne flotilla that would include a SIGSALY system. It took a minimum of 30 days to install high power radio systems and SIGSALY equipment on land. How fast the progress of island hopping would be was unknown therefore exact planning could not be made in advance. As it turned out because the U. S. gained supremacy on the sea; progress was much faster than thought. From Australia the U. S. moved to New Guinea Leyte, Luzon, and Japan and bypassed the other islands. Because of the earlier successes of the Army and the Navy Akin decided to move the SIGSALY flotilla to Luzon for the Philippine campaign. 

The requirements for a seaborne version of SIGSALY system were unique. The availability of this type of transportation was also limited. The U. S. ship building industry was busy building the Liberty ships, aircraft carriers, battleships, and other naval vessels that would be required for the war effort therefore building special ships for the Seaborne Communications Branch was not an option. General Akin decided on a type of ship known as an Ocean Lighter. This was a ship that was used around ports. It had a shallow draft and with the engine removed from the hold, it would provide a large space for equipment. A shallow draft was necessary because the ship would have to be stabilized to provide stability when operating the cryptographic equipment. The SIGSALY ship would be the OL-31. 

OL-31 U.S. Army Signal Corps seaborne communication branch 

General Akin requisitioned seven of these ships and they were found on Lake Michigan and brought down the Mississippi river to New Orleans. They were rushed from there to Brisbane in the summer of 1944 where they were converted for their communications function. 

Earlier, it had been planned to operate Terminal 9 of the SIGSALY network at a fixed location from Hollandia. On October 19, 1944, Lt. Colonel E. Nichols, acting Chief, Communications Engineering Branch of the Army Communications Service in Washington had requested the Signal Security Branch to set up a cryptographic system for SIGSALY connections between Terminal 5 at Hawaii and Terminal 9 at Hollandia. He anticipated that service would be needed in November of 1944. MacArthur’s plans changed and the service was not required from Hollandia.   

The first destination of the OL-31 was Hollandia, Dutch New Guinea. The vessel left Brisbane, Australia, on February 17, 1945 under tow of the U. S. Army tug St-17 and arrived at Townsville, Australia, on February 23rd. Repairs of the water pumps, deck engine clutch, and several leaks had to made at Townsville. Bad weather delayed the vessel until March 4th. It arrived at Thursday Island on March 13. After being held in port by storms, the vessel departed for Port Moresby, New Guinea. The storms continued and both the tug and the OL-31 went aground on a reef at Arden Island on March 21. After clearing the reef the tug and the OL-31 proceeded to Port Moresby, arriving there on March 23rd. Local divers inspected both ships. The OL-31 was found to have bent plates on the starboard side aft. Supplies and fuel were obtained and the vessels departed on March 28 headed for Milne Bay. A local pilot was aboard and the ships were routed inside of the New Guinea reef because of bad weather. The ships stopped at Milne Bay and Ora Bay. Rough seas were encountered before arriving in Hollandia on April 13, 1945. 

Signal Corps WWII Fleet Enroute To Hollandia 

The rest of Detachment 9 personnel and the remaining equipment for Terminal 9 traveled to Hollandia aboard the steamer U. S. A. T. Demund Chambers, leaving Brisbane on February 27 and arriving in Hollandia on March 13. All of the equipment was unloaded at Hollandia and trucked through rain and red mud to the signal depot for storage. Most of this equipment had to be stored outside and protected with tarpaulins.  

After the invasions of New Guinea and Leyte, the Fleet was used on even a larger scale in the next invasion, the island of Luzon where Manila is located. During the Luzon Campaign, General Akin’s flotilla increased to such proportions that it became known as the Signal Corp’s Grand Fleet. Its floating accommodations had more than doubled in number and capacity. Before the invasion of Luzon, additional vessels were planned which could carry larger installations. The spaciousness of the ocean lighters enabled the Signal Corps to carry the equivalent of an Army Communications System land installation with separate transmitter and receiver ships, message center accommodations, large antenna arrays, a barracks ship, and of course, a SIGSALY telephone system for top-secret conferences. Seven ocean lighters comprised this fleet and were acquired during April and May 1944. AN/TRC-1 VHF radios were used to interconnect the barges and land.

Manila Bay U.S. Army Signal Corps Seaborne Communication LinkThe seven ships or barges as they were called because they had no engines included the SIGSALY equipment ship. It was designated the OL-31. The SIGSALY equipment consisted of about twenty tall racks of equipment, two large 50 kilowatt generators, and a large air conditioning unit because all of this equipment had to be maintained at a constant temperature. The equipment had been designed for land installation with appropriate environment; however, the ship installation was a hostile environment. It was just the opposite of what the equipment was made for and it required much modification and innovation. The other ships of the flotilla were for receivers and the multichannel high powered transmitter for transmissions to the United States of the encrypted voice channel and multi-channel telegraph and teletype. Also there was a ship for barracks, since there was no room for sleeping quarters on the equipment ships. The remaining ships consisted of a message center and miscellaneous equipment.

AN/TRC-1 VHF radios were installed for communications between ships and shore. Because the equipment was leading technology and beyond the state of the art for the time and built to electrical and mechanical standards for American central office telephone systems, it was a real challenge to build the seaborne version of SIGSALY and required all the engineering expertise and innovative talent that could be obtained. It was this type of American ingenuity and “can do” spirit that brought the United States from the low point of unpreparedness at the start of World War 2 to the most powerful nation on earth at the end of the conflict.   

The saga of the OL-31 and this communications flotilla can best be told by two of the men who were there in their own words. They are members of the 805 Signal Service Company Sergeants Bud Brown and Curtis Martin. Overseas experience was a memorable time in any serviceman’s life. Several members of the 805th Signal Service Company have documented their experience aboard the OL-31 ship and provided an insight into what service aboard this floating terminal of SIGSALY was like. 

Following is a report that Sergeant Bud Brown wrote about his experiences on OL-31.

"I traveled on Ocean Lighter 31 with several of the Detachment 9 personnel from Manila to Tokyo during August and September 1945. Because the OL’s were not self-propelled, they were towed by three ocean-going tugs, each with a string of two or three OLs. The flotilla was escorted by two destroyer escorts. When we got to the open sea there were always three or four dolphins leading us at the bow of the ship and since the deck was only three or four feet from the water, flying fish easily landed on the deck. Our first stop was at Okinawa where we were moved into Katina Cove to ride out a typhoon that was in the area. On leaving Katina Cove, the Manila rope that connected us to the tug snagged on the bottom and had to be cut off and replaced by a smaller steel cable. From there the ride was rough because steel cable does not give like Manila rope and we felt every wave that hit the tug. As we proceeded, one of the OL’s in another string broke loose. A destroyer escort had to go back and retrieve it and was gone a couple of days before it appeared again towing the OL. Doing a tugs job seemed beneath the dignity of a destroyer. We arrived in Tokyo Bay opposite Yokohama on September 10, 1945, and were overwhelmed by the number and sizes of the U. S. Navy ships in the bay. We didn’t stay long, for a picketboat with a Japanese pilot was added to guide us through the minefields to Tokyo harbor where our trip ended alongside the dock. The Japanese indicated that the OL’s were the first U. S. ships in Tokyo Harbor."

Sergeant Curtis Martin describes his experiences onboard OL-31.                

"Although referred to as a barge, OL 31 had the configuration similar to an oil tanker with superstructure aft. We were towed by a large tug with approximately a mile-long cable. There were three tugs in all with two tugs pulling two OL’s and the other pulling one. Travel was very peaceful with dolphins, flying fish, barracuda, etc. during the day and the phosphorescence moon and stars at night. It was hard to believe that a war was going on. If my memory is correct, there were four other ships in the Seaborne Communications Fleet. These included the transmitter and receiver ships. We had very little contact with the others on these ships. They were very curious about the “Green Hornet” as our signal sounded to them.                

"Installation of our equipment on OL 31 was a challenge. Sergeants Durkin, Fruman, and myself, none with any experience in air-conditioning, built all of the ductwork and made the installation. We did have precise installation instructions from the York Corporation and it did work! We probably had one of the very few air-conditioned workplaces and sometimes living quarters in the South Pacific! Our power was furnished by three 50 kW diesel generators. We all had to learn to phase in the engine when switching from one to another. Our destination on leaving Okinawa was Tokyo. Fortunately we arrived after the surrender. The gathering of warships in Tokyo Bay was quite a sight.

"On July 7, 1944, the equipment and operating personnel arrived at Brisbane, Australia. The installation, which was in a vessel designated the OL-31, started on November 1, 1944, and was completed on February 1st. It left Brisbane on February 17 under orders to be towed to Manila. Somewhere off the northeast coast of Australia in the great Barrier area, the OL-31 was towed across a submerged corral reef causing some damage to the hull and shaking up the equipment considerably, necessitating readjustment and repairs. The vessel was delayed at Port Moresby and Ora Bay, New Guinea, for examination of the damage to the hull. It did not prove to be serious enough to warrant repairs, therefore, it continued north. The OL-31 arrived at Hollandia on April 12, 1944 and left on April 17, continuing to Manila. On May 10, the terminal arrived at Manila. Difficulties were experienced with the harbor authorities and it required 11 days to obtain a suitable site for docking the OL-31 vessel so that it could be placed into service. The site was assigned along the sea wall on the south side of the Pasig River just west of the Jones Bridge. On the night of May 21, the power and air-conditioning system went out of service due to the receding tide that permitted the OL-31 to settle on the bottom of the river. This permitted the circulating system’s intake to take in mud and sludge from the riverbed and clogged up the entire circulating system. This necessitated moving the vessel to deeper water and rehabilitating the circulating system.

"On May 23, 1945, Terminal 9 on OL-31 was turned up for service for the first time 10 months after its arrival in the theater. It was removed from service at Manila on June 23rd.

"Terminal 9 is the unit that was sent to the SWPA (Southwest Pacific Area) in May 1944, originally intended for installation at Hollandia, New Guinea. However, it was included in the sea-borne communications plan for SWPA and installed on a small barge referred to as an ocean lighter, which is a small barge type of vessel not capable of self-propulsion. The terminal installation was confined to the hold of the vessel occupying the forward two-thirds with the balance of the space aft devoted to power and air-conditioning equipment. Because of the limited space and particularly head-room, it was necessary to construct a false deck in order to provide sufficient clearance for the equipment bays and this only was possible by stripping the equipment of most of its cabinets and revising such other items so as to reduce the overall dimensions. Considerable modification was necessary in the air-conditioning system, outstanding of which was the Freon condensing and cooling unit which was a constant source of trouble since the installation was completed. It was learned from the Maritime people at Brisbane that the regular condensing and economizer unit normally used with the York air-conditioning system could not be used because of limited space. It would have been necessary to make this installation on deck which would have made the vessel top-heavy and rendered it unseaworthy.  

"As a substitute for the cooling and economizer unit, a special heat exchanger was built in Sidney, Australia for this installation that was capable of circulating salt water for condensation purposes. This was the basis of the air-conditioning system’s trouble because the Freon circulating coils were not designed for exposure to salt water. This resulted in electrolytic action to the coils and resulted in decomposition of the lines and leaks. The air-conditioning system capacity was 190 pounds. In four months over 1100 pounds of Freon were required to keep the system in operation despite the fact that the modified system only required 60 percent of the Freon as other terminal systems and the space to be air-conditioned was only 50 percent of that of other systems. The conference room for this terminal was only approximately 5ft. by 8 ft. with a 6 ft. ceiling. It was located on the main deck, was not air-conditioned, and was very poorly ventilated."

About August 10, 1945 Detachment 9 was alerted for duty with the advance echelon of GHQ Signal operations and on August 16 it left Manila for an indeterminate destination. The trip was made in convoy consisting of three U. S. Army large tugs towing seven Ocean Lighter ships escorted by two Navy Destroyer Escorts. The course was north along the west coast of Luzon and then northeast across the Pacific to Okinawa, arriving there on August 23rd. Due to a typhoon warning the OL-31 was moved into Katina Cove anchorage at the north end of the island and remained there until the storm had passed. On August 31, the convoy moved out to sea and the destination was now determined to be Tokyo, Japan. The occupation of Japan was underway and airborne occupation troops passed overhead while seaborne forces passed by the slow moving tugs. One of the Ocean Lighters broke loose from its tow. The Navy destroyer escort towed the OL for two days until the sea calmed enough to get it back into tow. The Seaborne Communications Fleet proceeded to Tokyo Bay and arrived on September 10, 1945, and went past the greatest array of warships ever gathered. The fleet proceeded up the bay, past Yokohama, and into Tokyo Harbor. The OL-31 went aground just off the breakwater that delayed it until dark and some trouble was encountered getting into port. A Japanese pilot came aboard and the OL at last reached the dock. It was the first Army ship to dock in Tokyo harbor. 

Since the small ocean lighter did not have quarters for the entire detachment some of them traveled in separate ships and rejoined the detachment later. The personnel who did not travel on the OL-31 from Manila to Tokyo boarded the U. S. S. Gasconade, a Navy transport in Manila Harbor on August 24, 1945. This ship joined a Task force and sailed the following morning in convoy with 34 other transports and eight escorts bound for Tokyo. The ship arrived in Tokyo Bay on September 1, 1945, and was part of the task force present in the bay when the surrender terms ending World War II were signed on the U. S. S. Missouri. The men disembarked at Yokohama, Japan, on September 2 and were among the first troops to enter Tokyo officially on September 7. They were attached to the 4025th Signal Service Group operating under the AFPAC Mobile Communications Unit. 

Terminal 9 on the OL-31 was made ready for operation and routine operations in Japan were started on September 21, 1945. 

With all of the technical and mechanical problems in installing and placing into operation the SIGSALY terminal aboard an ocean going barge, some readers may question whether it really was operational. I, the author, personally talked to the men aboard the OL-31 and set up conferences when it was in Manila Bay and I was in the Pentagon. Later I did the same when the OL-31 was in Tokyo Bay and I was in Manila. It operated perfectly. Support to make this installation successful was given by the Office of the Chief Signal Officer, the Western Electric Company and the 805th Signal Service Company who brought in equipment and supplies from other terminals when needed, and others.

The war ended on August 15, 1945 when the Emperor of Japan announced to the Japanese people that the fighting was over. SIGSALY and Detachment 9 of the 805th Signal Service Company arrived in Okinawa on August 23rd and left for Japan on August 31st where they established communications with the Pentagon and other terminals.

However, the outcome would have been very different if the bombs had been unsuccessful and the surrender had not occurred. Detailed plans had been made for the invasion and capture of Japan. This would have been the most colossal invasion in history. It would have been more than twice the size of the D-Day invasion of Europe. As many as one million casualties were expected. Two invasions would be required to obtain control of the country. First it would have been necessary to invade the island of Kyushu, the southernmost island, and finally the main island of Honshu. 

The invasion of Kyushu, known as operation Olympic, was scheduled for November 1, 1945. It was planned to use 800,000 troops. Against them would be 900,000 Japanese troops. The defenses would be terrific. In addition to the Japanese troops, the civilian population would join in the fighting. The Japanese were trained to use suicide tactics that would make the defense even more powerful. All of the power available to the Allies would be required. 

The logistics of the invasion would be extremely challenging. Okinawa was the closest location available to the Allies. It is approximately 500 miles from Kyushu. Guam and the Philippines are each 1,500 miles from Kyushu. Obviously, Okinawa would be the main launching point. Reinforcements and supplies would come from the other locations. Two thousand ships would be employed. Against this vulnerable invasion fleet for the 500 miles between Okinawa and Kyushu would be an estimated 5,000 Kamikaze suicide planes plus submarines. Twenty-five hundred carrier aircraft would be used in defense. In Europe, the distance traveled by the invasion fleet was less than 100 miles and the allies controlled the air. 

It would be very important to maintain secure communications to the Pentagon, Hawaii and other locations regularly in order to solve the unexpected problems that were sure to develop. A major communication facility would be required at Okinawa to reach Hawaii and Washington D. C. Terminal 9 on the ocean lighter and the other OL's would provide secure conferencing facilities. The Signal Corps Grand Fleet would provide other communications. It had been shown in the Philippines that this plan would work. 

When Kyushu was secured it would become the staging area and launching point for the invasion of the main island of Honshu. This would be called operation Coronet. It was scheduled for March of 1946. The fighting on Honshu would be even fiercer than on Kyushu. The battle of Okinawa had demonstrated the fight-to-the-death philosophy of the Japanese people. The preparations would have to be thorough and huge. The communications center for signal operations would now be shifted to Kyushu and the mobility of the Signal Corps Grand Fleet would prove its value. 

The invasion of Honshu would require sailing approximately 500 miles from Kyushu. There were 5,500 Kamikaze airplanes on Honshu ready to defend the main island. Even more troops than on Kyushu would be involved plus millions of civilians. What weapons would be employed is unknown. It is known that the use of midget submarines used in suicide attacks on allied ships was planned. Japan had used biological and chemical weapons in China. The casualties on both sides would be enormous. Fortunately, these operations were not necessary. 

The Signal Corps Grand Fleet and the 805th Signal Service Company were ready and capable of doing their part in the last great battle of World War II.   

Surrender In Tokyo Bay 

U.S. Army Signal corps Grand Fleet at anchor - 1945


Editor's Note: If you liked this article, read more by Candidate Don Mehl. Don wrote an article about the Japanese surrender and how it took place over the Signal Corps' SIGSALY Top Secret Communication system long before MacArthur got to Tokyo. You can read it in our archived collection of Home Pages. Click here to jump to the July 2012 archived Home Page and read Don's article Click to go to July 2012 archived Home Page. Don also wrote and published a full length book on the SIGSALY and SIGTOT crypto systems referred to in the article above. You can read about Don's book and even buy a copy of it on our PX page. Click here Click to go to July 2012 archived Home Page to learn more about and read a review of Don's book Top Secret Communications Of World War II.

Our special thanks to Don for taking the time to pen the wonderful story above; we offer him our most honored Signal Corps Salute.

This page originally posted 1 September 2012 

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