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USS Grayling (SS-209)

USS Grayling (SS-209) patch

The USS Grayling (SS-209) was a Gar-class World War II era submarine. The Gar-class boats were duplicates of the Tambor-class design. 1

The namesake of the USS Grayling is any freshwater fish of the genus Thymallus, related to the trouts, but having a longer and higher, brilliantly colored dorsal fin.

The radio call sign for the USS Grayling was NAN-EASY-KING-MIKE.

The Grayling returned to Fremantle from her seventh war patrol on July 6, 1943. Her captain, Lieutenant Commander John Elwood Lee, had been ordered to return to the States for new construction. For her eighth patrol, Rear Admiral Ralph Christie gave command of the Grayling to Lieutenant Commander Robert M. Brinker. 2

Following rest, refit, repairs, and drills, on July 30, 1943, the Grayling, captained by Lieutenant Commander Brinker, departed Fremantle for her eighth and final war patrol. On August 19, 1943, Brinker reported damaging a 6,000-ton freighter near Balikpapan. The next day he reported sinking a small tanker of the Taki Maru type in the Sibutu Passage with the Grayling's deck gun and taking one prisoner. This was the last report received directly from the Grayling3

Filipino guerrilla fighters reported by radio that on August 23, 1943, the Grayling had made a scheduled supply drop at Pandan Bay on Panay Island. 4

Upon completion of the supply drop, Brinker's patrol orders directed the Grayling to patrol the Tablas Strait through September 2, 1943, and then to patrol the approaches to Manila Bay until September 10, 1943, after which the Grayling would proceed to Pearl Harbor for a Navy Yard refit. Japanese records made available after the war confirmed that the Grayling sank the 5,480-ton passenger-cargo ship Meizan Maru off northeastern Mindoro Island, on August 27, 1943. The evidence supporting this sinking was sufficient for JANAC's award of full credit to the Grayling for it. However, she did not receive credit for the other two ships reported sunk by Brinker before the Grayling went missing. 5

Japanese records reviewed after the war also disclosed that on August 27, 1943, a torpedo attack was witnessed by enemy personnel and that on the following day a submarine was observed running on the surface. Both of these events occurred near the Tablas Strait off the southeastern coast of Mindoro Island. Japanese records also disclosed that an American submarine was seen on the surface in the Lingayen Gulf, on September 9, 1943. However, the Grayling had received specific orders to patrol the approaches to Manila Bay through September 10, 1943. The Lingayen Gulf is considerably north of that area; it is unlikely the Grayling would have been there at the time of the reported sighting. 6 Harry Holmes wrote that on September 9, 1943, the Japanese passenger-cargo vessel Hokuan Maru reported sighting a submarine in shallow water west of Luzon Island. The Japanese merchant sailed over the area where the submarine had been sighted and noted an impact with a submerged object. Holmes wrote the submerged object "...was, no doubt, Grayling." In typical Harry Holmes style, there is absolutely no attribution or source for these statements. I checked with my friends over at Tully's Port to see if they could shed any light on the Hokuan Maru's whereabouts during this time period. According to Peter Cundall, she arrived at Manila on September 4, 1943, and departed from there on September 7, 1943, in convoy 866 en route to Takao on Formosa, where she arrived on September 12, 1943, two days after the other convoy vessels got there. The Grayling should have been patrolling the approaches to Manila Bay until September 10, 1943, so it is possible that that their paths crossed. The problem is there is no conclusive evidence to prove there was an encounter between the Hokuan Maru and the Grayling. Thus the circumstances of the Grayling's loss remain a mystery. All that can be said with certitude is that the Grayling disappeared sometime after she sank the Meizan Maru, on August 27, 1943, at the geographic position 13° 35′ N, 121° 22' E. It is her last known position. 7

On September 12, 1943, the Commander Task Force 71 requested a radio transmission from the Grayling. A response was never received. On September 30, 1943, the Grayling was listed as lost in action with all hands. 8

The Grayling's loss was made public on December 24, 1943:

Navy Department Communiqué No. 491, December 24, 1943

1. The U. S. Submarine Grayling is overdue and must be presumed to be lost.

2. The next of kin of personnel in the Grayling have been so informed.

The Grayling received six battle stars for World War II service. The JANAC score for the Grayling is 20,575 tons of Japanese shipping sunk in five vessels, including the 5,480-ton passenger-cargo ship Meizan Maru. The Alden-McDonald score for the Grayling is nine vessels sunk for 22,272 tons and ten vessels damaged for 32,164 tons. The SORG score for the Grayling is 61,400 tons sunk in eleven vessels and five vessels damaged worth 36,600 tons. In the wake of the attack on Pearl Harbor, Admiral Chester Nimitz, the new commander in chief of the Pacific Fleet, made the submarine base at Pearl Harbor his temporary headquarters and declared the submarine USS Grayling his flagship. 9

A list of the personnel lost with the Grayling is maintained at On Eternal Patrol.

It is important to note that the Grayling has become the victim of erroneous reporting in many books and online sources. It is the type of error that grows ever bigger in its telling in new articles and books using the misinformation. It concerns what the Grayling did on her last patrol. A prime example is served up in the Dictionary of American Naval Fighting Ships. The online version of this publication states "Grayling began her eighth and last war patrol in July from Fremantle. She made two visits to the coast of the Philippines delivering supplies and equipment to guerrillas at Pucio Point, Pandan Bay, Panay, 31 July and 23 August 1943." 10 This is incorrect information because we know the Grayling departed Fremantle for her eighth and final war patrol on July 30, 1943; there is no way she could have made a supply drop at Pucio Point on July 31, 1943, nor was it a part of her orders to make more than one supply drop at that location. She would make one supply drop at Pucio Point, on August 23, 1943. Her patrol route and areas of operation had been carefully planned prior to her departure with her new captain, Lieutenant Commander Robert M. Brinker, in command. It was standard operating procedure for Ralph Christie's staff to carefully plan for the safe and coordinated use of all submarines at their disposal, right down to the route to be traveled and possible targets of opportunity in open sea areas. 11 In addition, a Spyron submarine would never be sent to the same location twice in a two-week period. It would be too dangerous for the crew and the guerrilla operatives. Supply drop locations and rendezvous points were changed regularly to keep the Japanese off balance and protect the submarines, their crews, and the shore-based operatives.

The Grayling had returned to Fremantle on July 6, 1943, completing her seventh and last patrol with Lieutenant Commander John Elwood Lee as her captain. Lee was being sent to the States for new construction. In the cover memo to his last patrol report Lee wrote that the Grayling was "...currently being refitted by Pelias in preparation for the Eighth War Patrol and no extension beyond the normal refit period is foreseen." The last such "normal refit period," at the conclusion of her sixth war patrol, lasted for twenty-three days. Twenty-four days elapsed between July 6th and the final departure of the Grayling on July 30, 1943, so Lee was spot on. 12

I believe the original source for the misinformation about the supply drops at Panay came from an addendum to United States Submarine Operations in World War II, by Theodore Roscoe. The addendum states that on July 31, 1943, the USS Grayling, captained by "Lieutenant Commander J. E. Leo" (sic.), "Delivered 2 tons of supplies and equipment at Pucio Pt., Pandan Bay, Panay, P.I." The same addendum states that on August 23, 1943, the USS Grayling, captained by Lieutenant Commander E. Olsen, "Delivered 2 tons of cargo at Pucio Pt., Pandan Bay, Panay, P.I." 13. The first entry was a mistake which was never corrected. I note that the second entry lists the wrong captain. Overall it serves as an example of how careful one has to be when using the data in Roscoe's book. Surprisingly, the error is perpetuated in Clay Blair's Silent Victory: The U. S. Submarine War Against Japan. However, Wilfred Jay Holmes got it right in his book Undersea Victory: The Influence of Submarine Operations on the War in the Pacific.

During my review of the Grayling's patrol reports, I noted the following information in her seventh war patrol report concerning problems with one of the boat's main generators. The issue was discussed in John Lee's covering memo and in section nine of the report, which dealt with major defects experienced during the patrol.

The following text is quoted from section nine.

(a) Main Generators - Megger reading on No. 4 Main Generator at beginning of patrol varied between 175,000 and 50,000 ohms. Reading is now steady at 50,000. This generator is considered unsafe except in an emergency. 14

The following text is quoted from Lee's covering memo.

GRAYLING returned from the patrol in a generally excellent material condition. Cleanliness of machinery and equipment was above even the usual high standard maintained by the submarines of this squadron. The GRAYLING is currently being refitted by Pelias in preparation for the Eighth War Patrol and no extension beyond the normal refit period is foreseen. Following the next patrol GRAYLING will be given a Navy Yard overhaul. All items listed by the Commanding Officer as major defects in paragraph 9 of basic report can be remedied by the tender force with the possible exception of number 4 main generator. The low ground reading described is caused by the accumulation of carbon dust mixed with oil which resists all efforts to remove it short of complete disassembly of the main generators. Complete disassembly is not considered practicable during tender refit periods but such cleaning as is possible without disassembly has to date maintained the grounds within safe limits even though they become lower on each successive patrol. Disassembly and cleaning of main generators should be accomplished during each Navy Yard period and if this is done it is considered that the tender can control the situation between Navy Yard overhauls. It is believed probable that the ground reading on number four generator of GRAYLING can be sufficiently increased during the current refit to enable safe operation of the generator during the next patrol. 15

I am not an engineer or an electrician, so I am not qualified to make a judgment as to what effect the "unsafe" generator might have had on the Grayling during her final patrol. In his memo, John Lee sounded fairly confident that the generator issue would not present a problem. However, it was listed as a "major defect," and I would be irresponsible if I did not disclose it as a possible issue. I am hopeful that someone with more knowledge about the main generators will contact me with their thoughts on this issue. My address is listed in my Contact Me webpage.

On April 14, 2014, I was very pleased to receive the following message from Robert E. Porterfield regarding the Grayling's problem generator. I am grateful to Mr. Porterfield for his input on this matter.


After reading the entry on Grayling, I had to dip my oar into the water regarding the problem generator. My perspective on this issue is based in part on my training and service as an electrician’s mate aboard submarines. Following my naval service, I obtained a degree in electrical engineering and have been practicing engineering since.

Generator No. 4

Regarding Grayling’s main generator problem, I offer the following based on the method of calculating insulation resistance presented in Figure 7-3 of SUBMARINE ELECTRICAL INSTALLATIONS (NavPers 16162). The table provides a method for establishing minimal acceptable levels of insulation resistance based on the rated voltage of the generator (415 Vdc for Tambor and Gar class) and the rated power of the generator in kilowatts (1100 kW for these boats). The table deals with three conditions: 1) Before Cleaning Dirty Machines in Vessel, 2) After Cleaning in Vessel, and 3) After Reconditioning in Shop. The values obtained using the "Before Cleaning" methodology are the minimum levels of insulation resistance at which cleaning, drying, or repair should be initiated. These values for Grayling’s generator would have been:

Complete armature circuit: 0.12315 megohms (123,150 ohms)

Armature alone: 0.18472 megohms (184,720 ohms)

Armature circuit less armature: 0.18472 megohms (184,720 ohms)

Complete shunt field circuit: 0.82097 megohms (820,970 ohms)

Chapter 60, Electric Plant - General, of the BuShips Tech Manual, the "Bible" for operating shipboard systems and equipment, provides a table similar in content to that presented above, but with somewhat increased values for the Armature Alone and Armature Circuit Less Armature (0.20524 megohms in each case).

The excerpt from the patrol report cited on your webpage indicates that megger readings "varied between 175,000 and 50,000 ohms" and near the end of Grayling’s patrol the megger reading was "steady at 50,000" ohms (0.05000 megohms).

I believe it may be taken for granted that E-division personnel spent a great deal of time in trying to clean up the machine. This belief is based on Section 60-139 of the BuShips manual which states, in part: "Values in the ‘Before cleaning’ columns … are the values of insulation resistance at or below which the machines should be removed from service and thoroughly cleaned, dried out, or repaired as necessary. Values less than those given in the ‘Before cleaning’ columns should not be construed as necessarily indicating an unsafe condition or one which would prohibit the use of a machine if necessary. However, when values less than those are obtained for a machine, use of the machine should be avoided if practicable and action should be taken on the first opportunity to find and remedy the cause of the low insulation resistance."

The acceptable insulation resistance after cleaning aboard a vessel, per Figure 7-3, cited above, should be as follows:

Complete armature circuit: 0.61573 megohms (615,730 ohms)

Armature alone: 0.92359 megohms (923,590 ohms)

Armature circuit less armature: 0.92359 megohms (923,590 ohms)

Complete shunt field circuit: 2.05242 megohms (2,052,420 ohms)

At 50,000 ohms, No. 4 generator’s insulation resistance was significantly less than any of these minimum levels. Operating it could have resulted in significant damage to the generator, the engine, and other components of the boat’s electrical system. The hazard to personnel would also have been increased. For example, a fire in the generator could have resulted. Such fires are difficult to extinguish since some suppression agents cannot penetrate the windings to get at the seat of the fire. Injection of CO2 can be effective if a suitable concentration can be established and maintained for sufficient time for the generator components to cool below their ignition point. This approach could be problematic aboard a submarine at sea because only a limited number of fire extinguishers are carried. Further, an extended fire in the generator could generate significant heat and smoke, forcing evacuation of the engine room which contained all four of the boats engines and generators. Of course a number of other possibilities can be hypothesized.

I had some experience with trying to clear a low insulation resistance problem (ground) in a fully enclosed machine smaller than the Grayling’s generator, but equally difficult to access. The commutator had been stoned in place and the residue from that work had been distributed throughout the machine by air circulation from the shaft mounted cooling fan. There was no oil in the mix, making the residue easier to remove than Grayling’s sailors would have experienced. Even so, a significant number of man hours was expended over several days before a satisfactory result was obtained. I can imagine that had we also had an oil problem, this effort may not have been successful.

The construction of these machines is such that really effective cleaning can only be accomplished by pulling the armature out. This is not a practical practice aboard the boat.

Operational Impact

The Tambor and Gar class submarines had four main engines. each of which drove a generator. None of the engines were directly connected to the propellor shafts as had most earlier classes of boats. Thus, if a generator was considered unsafe to use, the boat became, in effect, a three engine vessel. The effect of this limitation on operations could be significant, particularly when operating in a war zone where enemy surface ASW forces were concentrated and where the enemy had control of or significant presence in the air.

These boats could make somewhat over 20 knots on the surface, but to do this four generators were required to be closed in on the motor bus. With only three generators available, Grayling’s best speed would be limited to about 17 knots. At least one generator would be required for battery charging when that was needed. That would leave only two generators for propulsion. The best speed in this circumstance would be 14 knots. Following lengthy or extended high speed submerged operations, two engines might be needed for battery charging for a time. This would leave a single generator for propulsion and the boat’s speed would be limited to about 11 knots.

From this it can be seen that Grayling’s ability to make high speed runs for transit, attack, or evasion would be compromised. Situations in which the boat could outrun ASW vessels on the surface would be very limited. The ability to make an end around to put the boat in a favorable attack position on a target would also be limited. To quote Cdr. John Alden from page 91 of his book, The Fleet Submarine in the U. S. Navy, "Two knots may not seem like much … but it made all the difference in the world to a submariner trying to get into a friendly rain squall to hide from some very unfriendly Japanese patrol boats or destroyers."

NOTE: The data regarding speed capabilities were taken from Chapter 7, pages 7-39 through 7-42 of a text produced by and used at the Submarine School in New London in the Advanced Submarine Electrical Course offered to Electrician’s Mates assigned to submarine duty. This text should not be confused with Submarine Electrical Installations, NavPers 16162.

Thanks for lending an ear,


Robert E. Porterfield

Patrol Data & Tonnage Scores


1. Alden, John D., The Fleet Submarine in the U. S. Navy: A Design and Construction History, p. 74.

2. Blair, Clay, Jr., Silent Victory: The U. S. Submarine War Against Japan, p. 397. Also see Submarine war patrol reports on CD, USS Grayling (SS-209), Report of Seventh War Patrol, p. 117.

3. See USS Grayling (SS-209) in United States Submarine Losses World War II, p. 52.

4. Ibid.

5. Ibid.

6. Ibid.

7. Holmes, Harry, The Last Patrol, p. 54; also see Peter Cundall's comments online at Tullys Port at, in the topic "TROM for Hokuan Maru"; and Casse, Gilbert, and Bob Hackett, "HOKUAN MARU: Tabular Record of Movement," published online at Combined Fleet; Alden, John D., and Craig R. McDonald, United States and Allied Submarine Successes in the Pacific and Far East During World War II, Fourth Edition, see USS Grayling (SS-209), Attack No. 1059.

8. See USS Grayling (SS-209) in United States Submarine Losses World War II, p. 52.

9. Sturma, Michael, Surface and Destroy: The Submarine Gun War in the Pacific, p. 16; Alden, John D., and Craig R. McDonald, United States and Allied Submarine Successes in the Pacific and Far East During World War II, Fourth Edition, see USS Grayling (SS-209), Attack Nos. 120, 122, 274, 416, 427, 448, 579, 586, 607, 704, 709, 731, 732, 735, 736, 747, 755, 862, 891, 905, 910, 1032, 1039, and 1059; Submarine war patrol reports on CD, USS Grayling (SS-209), data collected by the Submarine Operations Research Group (SORG) in the report "Results of U. S. Submarine War Patrols Listed Alphabetically by Name of Submarine"; Japanese Naval And Merchant Shipping Losses During World War II By All Causes, Joint Army-Navy Assessment Committee, USS Grayling (SS-209).

10. Dictionary of American Naval Fighting Ships, USS Grayling (SS-209).

11. Campbell, Douglas A. Eight Survived: The Harrowing Story of the USS Flier and the Only Downed World War II Submariners to Survive and Evade Capture, p. 123-124.

12. See Submarine war patrol reports on CD, USS Grayling (SS-209), Report of Seventh War Patrol, p. 137.

13. Roscoe, Theodore. United States Submarine Operations in World War II, p. 512-513.

14. See Submarine war patrol reports on CD, USS Grayling (SS-209), Report of Seventh War Patrol, p. 135.

15. Ibid., p. 137.