THE LYNCH PLOT
THE FIRST BEARINGS-ONLY SOLUTION
A few years ago when Frank Lynch entered my office, he was surprised to see a reproduction of the deck and frame plans of the R-1 (SS No. 78), which I had hanging in a prominent position in my office. He walked to the picture, pointed to the crew’s mess table, and with considerable enthusiasm exclaimed, “‘That is the table where I drew the first diagrams that led to the development of the Lynch Plot”. He then told me the following story, which marks the beginning of the development of modem passive sonar bearings-only target motion analysis techniques; a function that is vital to modem submarine warfare.
The R-1 was built in World War I and then decommissioned after the war ended. In 1940 the submarine was tested briefly at New London, found not to leak too badly, recommissioned, and deployed to Panama with Frank as third officer.
Soon after arriving in Panama, the R-1 was fitted with her first sonar system, which arrived in a crate from the United States, and was installed by the ship’s company with little or no assistance. Those who are involved with today’s AN/BQQ and AN/BSY systems find that a remarkable contrast to current installation procedures.
The R-1 was to conduct several fully submerged torpedo attacks to complete the checkout of her new sonar system. A day or so before getting underway, Frank was tasked to develop a procedure for conducting a “sound onlyn attack. A quick inquiry on the other submarines in the area revealed that no one knew how to carry out an attack without using numerous periscope observations.
Starting with a blank piece of paper, and a remarkable insight to kinematics, Frank spent long hours plotting various submarine and target encounter geometries. He searched for relationships among a series of sonar bearings, own ship course and speed, and target course and speed that could be used to determine the required torpedo gyro angle. The pivotal relationship he found was between bearing, bearing rate, and the target’s line of relative motion. He told me that the night before the R-1 sailed he discovered that using observed bearing rate as a measure of target motion caused seemingly distinct encounter geometries to reduce to similar triangular diagrams! The R-l’s exercise torpedo attacks were conducted using a maneuvering board upon which a series of bearings -observed with a faxed time interval between them — was plotted.
During the following weeks Frank said little and spent his evenings plotting submarine attack geometries. As a result of those evenings he perfected the Lynch Plot, the first bearingsonly TMA technique. Lynch plots were used throughout World War II on the SS HARDER and then on the SS HADDO. After the war, the Lynch Plot was among the warproven fire control techniques that were documented and introduced to the Submarine School curriculum. The Lynch Plot remained part of the curriculum into the 1960’s. Lynch Plot devices are still in the submarine force’s inventory of tactical aids, although their use has been supplanted by modem onboard computers.
After the war, Frank was assigned to Washington, D.C. where he worked in submarine fire control development. While there he succeeded in having an indicated bearing-rate display added to position keepers. He was proud to have made that contribution to submarine combat systems. What has remained unsaid was that Frank Lynch was the grandfather of modem submarine bearings-only attack techniques.
David C. Ghen
CONVOY MO-TA-30
Thanks for giving me the opportunity to review — before publication — the MO-T A30 convoy story.
In 1946 Karl Hensel informed me that JANAC had found the BARB had sunk ANYO, SHINYO, HIKOSHIMA, and SANYO Marus in the day-night battle on 8 January 1945 in Formosa Straits, at the times and places stated by BARB in her patrol report.
All of the U.S. wolfpack agree that there were only eight large ships and nine escorts, five of which were PCs or subchasers. Tokyo Archives listed 9 ships plus frigates 26, 36 (flag), 39, 67 with unknown number of PCs. This April, my Tokyo friends notified me that the ninth ship (Daiyu Maru) did not join the convoy.
All Japanese ships invariably use Tokyo time (ITEM), so to make sense shift our wolfpack times from HOW to ITEM.
It was a three echelon convoy: Starboard echelon, three ships, all engines aft, lead ship brand new modified standard cargo. This jibes with Shinyo Maru – 6892T. on maiden voyage loaded with ammunition picked up at Dairen – followed by Sanyo M. -2854T. diesel fuel. Center echelon, transport Anyo M. – 925Tf. surrounded by four PCs followed by two MFM stragglers which by deduction can only be the Rashin Maru and the Manju M. the port echelon was led by the passenger freighter Hisakawa M – 6886T. (troops, vehicles, horses) with the Meihu Maru- 285Tf. astern.
BARB fired at Sanyo with Hisakawa overlapping ahead at 1824 (1). Two fish hit the Anyo and one ftsh hit Hisakawa. At 1825 (I) BARB fired three fish at the Shinyo (Passengers, ammunition) which exploded at the first hit, driving BARB sideways and down to 80 feet, tearing off deck gratings aft. Returned quickly to periscope depth. There was only smoke where the Shinyo had been, only the stern of the Anyo was sticking up at a 30 degree angle with two escorts alongside taking off survivors, and Hisakawa was aflame above the waterline. The rest of the convoy changed course from 143 to 030. The explosion and fire were witnessed by packmates at great distance who also noted that two ships disappeared.
Back Channel intercept reported Anyo sank first and Shinyo Maru, a modified freighter, sank at 1830 (1). The Second Repatriation Agency reported that on 8 January the Tatsuyo (Shinyo) was sunk at this spot by AIR and the Hisakawa received heavy damage by AIR. (There were, however, no air attacks in the straits until late morning on the ninth.)
At 1900 the convoy reformed in two columns and headed south, probably in this order. Starboard column, Rashin Maru, Manju M., Sanyo M., Hikoshima M. Port column (500 yards from Sanyo ), Hisakawa M., Meiho M. Night very dark. At 2010, attacking from starboard bow, QUEENFISH fired 6 fiSh at Rashin and Manju, then 4 fiSh at Hisakawa. All missed.
At 2054, attacking from starboard bow, PICUDA picked out two large AKs, passenger freighters with composite superstructures, and fired three fiSh at Rashin (certain) for one hit and three at Manju (most probable, for at 1500 yards broad on her bow she looks like a passenger-freighter) for one hit. She then set up for a stem shot at the next tanker in the starboard column, the Sanyo, which turned away. Convoy did not slow, but Rashin and Hisakawa both headed for the coast, probably ready to beach if necessary to avoid sinking.
BARB had been held down by escorts after her submerged attack, reloaded and surfaced at 1956. BARB then attacked from astern working up the escort line acting like an escort.
At 2115, attacking from starboard escort line, BARB fired 3 fiSh at Hikoshima-Meiho overlap for two hits in the first and one in Meiho. One ship sank and the other, damaged, headed toward the beach. Moving ahead of the next escort, but staying in line, BARB attacked again up the line.
At 2133 she fired 3 fish at the Sanyo M. which, full of avgas, erupted. The escorts went full speed for the minefield slot near Formosa. Again BARB moved up, but there was only one ship left. As we closed in to fire, QUEENFISH (Loughlin) sent a message, “Hey, save one for me!” I gave him a green light, and the course and speed of convoy. BARB passed this last ship at less than 2,000 yards. Only escorts were ahead. Elliott hit her with two torpedoes. Stopped, she opened fire, as did escorts and shore batteries, thinking they were being bombed. Believing QUEENFISH had been forced down, and the ship was not sinking fast enough, I backed in for the coupe de grace at 1500 yards, covered by the smoke from her guns and opened the outer doors. Just then she started to settle rapidly. Her guns ceased fire as her decks were awash. PICUDA had gone on way ahead and found the sole surviving ship Rashin, fired 4 fish and missed. Nothing else was afloat.
Tokyo Archives assured me that all eight ships in this convoy were sunk, damaged or beached, even the Rashin Maru. Yet the air arms, in their raids in the following day and bombing of long stranded ships later, laid claim to half of them without giving any credit to the subs who put them in that position. Somehow the Hisikawa Maru was abandoned by escorts somewhere in the Formosa Straits after grounding once because she was heavily damaged. She was alone when she took a bomb hit on 9 January and sank later. Exactly where, is a mystery. There are several versions of the demise of the Hisakawa. She was definitely alone at the end and no survivors are known. After being hit by BARB, receiving heavy damage and set afire, she may have rejoined the convoy for a short time, then beached herself after PICUDA attack on Rashin and Manju. Rashin left the convoy at that time and Hisakawa was no longer present. At 0850 Jan 9th the Rashin and two frigates encountered her (no position mentioned). She may have received additional damage during the 0915-1000 air raid, because Rashin and escorts left her alone. During the noon air raid, on the ninth, though there was no report of her being hit, she sent her final message at 1320 reporting she was sinking. The escort war diary states she sank at 1255 at 230-4N, 120-35E which is 32 miles inland.
Rear Admiral Gene Fluckey, USN(Ret.)
SUBMARINE JACKET PATCHES
I am doing some research on the origin and early history of submarine jacket patches, of which I have a large collection.
I would like to hear from anyone having knowledge of submarine jacket patches in use earlier than 1963, their origin, boats that had them, where they were obtained, etc. Please contact John D. Alden, CDR,USN(Ret.), 98 Sunnyside Avenue, Pleasantville, NY 10570.
John Alden
USNA SERVICE SELECTION NIGHT
Dear Admiral Long,
Service selection night for the Class of 1989 was held on Tuesday, 7 February 1989. I am happy to report that of the 977 men in the class, 181 chose submarines as their career path. As each of the submarine candidates completed his choice of Nuclear Power School dates, he was welcomed into the Submarine Force by our USNA submariners to the accompaniment of a claxon. Each was then presented a check representing a bonus for selecting nuclear power training. In addition, they were each presented, courtesy of the Naval Submarine League, a Dolphin lapel pin, a complimentary membership card and membership certificate, and your letter of welcome.
Each of these prospective submariners most certainly felt warmly welcomed into our community. Thank you for supporting our efforts to recruit the highest quality midshipmen for the submarine force and in providing a warm welcome to them.
V.L. Hill, Jr.
Rear Admiral, U.S. Navy
Superintendent, USNA
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CHAPTER NEWS
PACIFIC SOUTHWEST CHAPTER
The Pacific Southwest Chapter membership consists of 543 in California, 9 in Arizona, 6 in New Mexico, 1 in Nevada, 1 in Utah, and 7 in Colorado for a total of 567. There are approximately 200 members in the San Diego area.
PACIFIC NORTHWEST CHAPTER
At the April 22 meeting, the chapter elected Capt Guy A Grafius, USN(Ret.}: President, Paul A Robinson: Secretary and Capt Richard E. Tennent, USNR: Treasurer.
Because of the geographic dispersion of the membership, the Pacific Northwest chapter elected two vice presidents, one for Puget Sound West side (Willis A Lent, JR.) and one for Puget Sound EaSt Side (Capt Donald M. Ulmer, USN(Ret.). the intent is for each side to hold quarterly or semi-annual meetings separately and then to have one combined annual meeting.
