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Career information

Commanded USS Seahorse 1st Patrol 1943. Removed from command at the end of this patrol for lack of aggressiveness. Relieved by Lt. Cdr. Slade Cutter October, 1943.

Submarine USS Gar (206)

2 Feb 1942
USS Gar (Lt.Cdr. Donald McGregor) departed from Pearl Harbor for her 1st war patrol. She was ordered to patrol in Japanese home waters.

13 Mar 1942 (position 33.53, 139.29)
USS Gar (Lt.Cdr. D. McGregor) torpedoed and sank the Japanese merchant Chichibu Maru (1520 GRT) about 10 nautical miles south-west of Mikura Jima, south of Tokyo Bay, Japan in position 33°53'N, 139°29'E.

28 Mar 1942
USS Gar (Lt.Cdr. D. McGregor) ended her 1st war patrol at Pearl Harbor.

19 Apr 1942
USS Gar (Lt.Cdr. D. McGregor) departed Pearl Harbor for her 2nd war patrol. She was ordered to patrol off the Marshall Islands.

8 Jun 1942
USS Gar (Lt.Cdr. D. McGregor) ended her 2nd war patrol at Fremantle, Australia.

3 Jul 1942
USS Gar (Lt.Cdr. D. McGregor) departed Fremantle for her 3th war patrol. She was ordered to patrol in the South China Sea and the Gulf of Siam.

21 Aug 1942
USS Gar (Lt.Cdr. D. McGregor) ended her 3th war patrol at Fremantle.

17 Sep 1942
USS Gar (Lt.Cdr. D. McGregor) departed Fremantle for her 4th war patrol. She was ordered to patrol in the South China Sea and the Gulf of Siam. Also so was ordered to lay mines in the entrances to Bangkok.

20 Oct 1942
USS Gar (Lt.Cdr. D. McGregor) lays 32 mines in the approaches to Bangkok.

7 Nov 1942
USS Gar (Lt.Cdr. D. McGregor) ended her 4th war patrol at Fremantle.

Submarine USS Seahorse (304)

2 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises in the San Francisco area.

3 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises in the San Francisco area.

4 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises in the San Francisco area.

11 Jun 1943
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises in the San Francisco area.

16 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises in the San Francisco area.

17 Jun 1943
USS Seahorse (T/Cdr. D. McGregor, USN) departed the Mare Island Navy Yard for San Diego.

On leaving the San Francisco area the following morning she was joined around 0830T/18 by USS Lawrence (T/Cdr. T.B. Hutchins, 3rd, USN) as escort.

Around 0735T/19, USS Lawrence was relieved by USS Boyd (T/Cdr. U.S.G. Sharp, Jr., USN).

USS Seahorse and USS Boyd arrived at San Diego around 1445T/19.

20 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) departed San Diego for exercises. She returned to San Diego the following day.

22 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises off San Diego

23 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) departed San Diego for exercises. She returned to San Diego the following day.

25 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) departed San Diego for exercises. She returned to San Diego the following day.

27 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises off San Diego

28 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises off San Diego

29 Jun 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) departed San Diego for exercises. She returned to San Diego the following day.

1 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises off San Diego

2 Jul 1943
USS Seahorse (T/Cdr. D. McGregor, USN) departed San Diego for exercises with USS Crane (T/Cdr. H.N. Coffin, USN). They were escorted by USS PC-579 (Lt. F. Seymour, USNR).

On completion of the exercises USS Seahorse was to proceed to the Mare Island Navy Yard.

6 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) arrived at the Mare Island Navy Yard from San Diego.

7 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises in the San Francisco area.

16 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) departed the Mare Island Navy Yard for Pearl Harbour.

24 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) arrived at Pearl Harbour from the Mare Island Navy Yard.

27 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises off Pearl Harbour.

28 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) conducted exercises off Pearl Harbour.

29 Jul 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) departed Pearl Harbour for exercises with USS Allen (T/Lt.Cdr. H.H. Nielsen, USN) and USS Chickasaw (T/Lt. J.F. King, USN).

They remained out for night exercises.

In the morning of 30 July, USS Wahoo (T/Cdr. D.W. Morton, USN) joined the exercises.

On completion of the exercises in the afternoon of 30 July.

3 Aug 1943
Around 1500VW/3, USS Seahorse (T/Cdr. D. McGregor, USN) departed Pearl Harbor for her first war patrol. She was to patrol off the Palau Islands.

Before proceeding to her patrol area she was to top off with fuel at Johnston Island.

USS Seahorse was escorted out until dark by USS PC-589 (Lt.(jg) J.K. Miller, USNR). (2)

5 Aug 1943
Around 1130X/5, USS Seahorse (T/Cdr. D. McGregor, USN) arrived at Johnston Island to top off with fuel. She departed for her patrol area around 1530X/5. (2)

17 Aug 1943
Around 1100I/17, USS Seahorse (T/Cdr. D. McGregor, USN) arrived in her patrol area. (2)

18 Aug 1943 (position 0.00, 0.00)
At 1135I/18, while patrolling three miles to the north of Malakal harbour, Palau, USS Seahorse (T/Cdr. D. McGregor, USN) sighted two small patrol vessels which located the submarine by echo ranging. At 1239I/18, a third patrol vessel, equipped with more powerful sound gear joined the other two. USS Seahorse sought refuge at 275 feet underneath a temperature gradient and evaded the enemy patrol craft.

20 Aug 1943
At 0750I/20, while patrolling five miles to the east of Peleliu, Palau, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a small diesel engined patrol craft which was echo ranging.

At 1107I/20, a two-masted, inter island type patrol vessel of about 1200 tons was sighted three miles to the east of Peleliu.

At 1452I/20, smoke was seen in position 07°01'N, 134°25'E. The source of the smoke was proceeding on a course of approximately 160°.

At 1845I/20, having surfaced, a high speed search of the area but no target was encountered and the search was abandoned at 2307I/21 and course was set to patrol in the vicinity of the Malakal passage. (2)

22 Aug 1943 (position 0.00, 0.00)
At 0804I/22, while patrolling off the Malakal passage, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a patrol boat near the entrance of the passage. (2)

23 Aug 1943 (position 0.00, 0.00)
At 0613I/23, while patrolling off the Malakal passage, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a small patrol boat.

At 0723I/23, USS Seahorse started the approach on a small steamer which was seen hull down. This turned out to be a patrol boat about 3.5 nautical miles from the Malakal harbour entrance.

At 1423I/23, another small patrol boat was sighted. (2)

24 Aug 1943 (position 0.00, 0.00)
At 0122I/24, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a submarine chaser type patrol boat on the edge of a rain squall.

Two minutes later the enemy opened fire on the submarine from a range of about 1500 yards using flashless powder. The first two shots passed close to but over the conning tower. The next two exploded in the water abeam while USS Seahorse was crash diving. Six depth charges were subsequently dropped of which the last two were fairly close.

Around 0600I/24, the pinging of the submarine chaser was fading out.

At 2100I/24, the same ship was sighted at a range of 4000 yards and was evaded. (2)

25 Aug 1943 (position 0.00, 0.00)
At 1016I/25, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a trawler type patrol boat at a range of 4000 yards. Contact was lost around 1330I/25.

At 2158I/25, a submarine chaser type patrol vessel was sighted at a range of 3000 yards. This vessel was evaded on the surface. (2)

26 Aug 1943
At 0501I/26, south-east of Babeldaub, Palau, in position 07°13'N, 134°41'E, USS Seahorse (T/Cdr. D. McGregor, USN) sighted two unidentified patrol vessels. To avoid being sighted USS Seahorse was forced to dive early.

At 1028I/26, an inter island type patrol vessel was sighted off the entrance to Malakal harbour. She remained in sight until around 1500I/26.

At 1030I/26, at least three sources of smoke were seen leaving Malakal harbour through the western entrance. (2)

28 Aug 1943
At 1003I/28, while off Malakal harbour, USS Seahorse (T/Cdr. D. McGregor, USN) picked up echo ranging from four different directions. Only some small patrol vessels were in sight.

At 1135I/28, in position 07°07'N, 134°25'E, masts were seen which developed into a convoy of three transports and two escorts. Range was 16000 yards. Enemy course was about 140°, speed 8 knots. It was not possible to close the range while submerged but increased speed to track and then surface after dark to overtake and attack.

At 1800I/28, USS Seahorse surfaced before sunset taking the chance of not being sighted by the enemy air patrol for the convoy. Proceeded at full speed.

At 2025I/28, contact on the convoy was regained. Tracked the convoy on a course of 140° at 8 knots. Commenced an end around to get ahead of the convoy to attack.

At 0502I/29, USS Seahorse dived ahead of the convoy.

At 0519I/29, USS Seahorse was about 4000 yards from the leading transport. One of the escorts obtained A/S contact and soon showed two green vertical lights and then turned towards at full speed. USS Seahorse went to full speed and changed course to complete the attack on the transport but the actions of the escort forced USS Seahorse to break off the attack and go deep.

Between 0525I/29 and 0539I/29, 15 depth charges were dropped the first 5 rather close. Both escorts were now hunting.

At 0717I/29, 4 depth charges, set deep, exploded which rocked USS Seahorse which was at 300 feet. Some minor damage was caused.

By 1000I/29, pinging started to fade out and at 1059I/28, USS Seahorse surfaced. SD radar showed 1 to 3 aircraft patrolling in the area. Commenced to search for the convoy while making some repairs to the induction piping when sea conditions permitted.

The convoy was not found again and at 1807I/30 the search for it was abandoned. Course was set to patrol off the Toagel Mlungui passage off the west coast of Babeldaob Island.

The convoy encountered was most likely ' Convoy Wekak 7 ' made up the transports Aden Maru (5860 GRT, built 1919), Hankow Maru (4104 GRT, built 1919), Nagano Maru (3810 GRT, built 1917), Nagato Maru (5901 GRT, built 1918) and Shinyu Maru (4614 GRT, built 1919) escorted by the submarine chasers Ch-26 and Ch-34 (all links are offsite links). (3)

31 Aug 1943 (position 0.00, 0.00)
At 1531I/31, USS Seahorse (T/Cdr. D. McGregor, USN) sighted smoke bearing 018°. Commenced tracking.

At 1606I/31, a second source of smoke was sighted bearing 138°. This smoke was heavier and USS Seahorse was right on it's track.

At 1625I/31, USS Seahorse submerged and commenced an approach on the source of the smoke which was proceeding on a course of 320° at slow speed.

At 1800I/31, when about to complete the approach and then attack, the target turned on lights showing herself to be a hospital ship.

At 1825I/31, USS Seahorse surfaced and made off to search for the source of the smoke that had been sighted at 1531I/31. The search was abandoned around 0008I/1 after nothing had been encountered. (2)

3 Sep 1943 (position 0.00, 0.00)
USS Seahorse (T/Cdr. D. McGregor, USN) commenced to patrol off the Toagel Mlungui passage off the west coast of Babeldaob Island. (2)

4 Sep 1943 (position 0.00, 0.00)
At 0706I/4, off the Toagel Mlungui passage, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a small diesel patrol vessel which remained in the area until 1145I/4.

At 1755I/4, a two-funnelled steamer was seen leaving the Toagel Mlungui passage. The steamer proceeded on course 270° at 11 knots.

At 1850I/4, USS Seahorse surfaced and proceeded in pursuit of the steamer.

At 2010I/4, USS Seahorse overhauled the steamer but it was found to be a properly marked hospital ship. (2)

5 Sep 1943 (position 0.00, 0.00)
At 0801I/5, near the Toagel Mlungui passage, USS Seahorse (T/Cdr. D. McGregor, USN) sighted an enemy patrol vessel.

At 0932I/5, an enemy transport was seen to be underway inside the reef. USS Seahorse proceeded to the front of the pass so as to be in position if this ship would come out.

At 1042I/5, a ship was seen outside the entrance to the pass and an attack was started but this was broken off when it was seen that the ship was a trawler type patrol vessel. The transport did not came out and must have relocated inside the reef. It could no longer be seen against the background of high hills and in the hazy rain. (2)

6 Sep 1943 (position 7.31, 134.21)
USS Seahorse (T/Cdr. D. McGregor, USN) is damaged by depth charges while attacking a convoy off Palau in position 07°31'N, 134°21'E. Despite being damaged she was able to remain on patrol.

The ships attacked must have been from convoy ' No. 3111 ' (Manila - Palau) made up of 8 transports escorted by the destroyer Karukaya. Four of the transports have so far not been identified, the other four were the Maebashi Maru (7005 GRT, built 1921), Shinsei Maru No. 1 (5864 GRT, built 1919), Taian Maru (5755 GRT, built 1916), Tencho Maru (2716 GRT, built 1919).

Possibly on approaching Palau the convoy had split up to proceed to different anchorages reinforced by local escorts.

Despite the claim for three hits no damage was caused. Possibly this is yet another example of the premature exploding American torpedoes.

0715I/6 - While patrolling off the reef near the Toagel Mlungui passage off the west coast of Babeldaob, Palau, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a trawler type patrol vessel.

0836I/6 - Smoke was seen and a submerged approach was started.

0845I/6 - The smoke was seen to be originating from a convoy made up of two transports which were escorted by a patrol vessel and a gunboat which were approaching the Toagel Mlungui passage at 8 knots. An attack was started.

1045I/6 - In position 07°31'N, 134°21'E, USS Seahorse fired four bow torpedoes on one of the transports, estimated as being around 7500 tons and loaded with troops. Three hits were claimed and about 1.5 minutes after the last hit two heavy explosions were heard thought to be originating from the target. Three minutes after firing depth charging started. A total of 35 were counted and some were fairly close causing damage to USS Seahorse. Enemy course had been 035°, speed 7 knots. Range on firing was 2000 yards.

The enemy kept on hunting the submarine until around 1700I/6. (3)

7 Sep 1943 (position 0.00, 0.00)
At 0506I/7, while closing the Toagel Mlungui passage from the north-west, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a patrol vessel which was difficult to see against the background. At the same time the SJ radar reported a contact at 2400 yards. USS Seahorse submerged and took avoiding action. Apparently she had not been sighted.

At 0545I/7, a second patrol vessel was heard and sighted. An efficient patrol by these two vessels kept USS Seahorse from approaching the reef. Apparently the enemy were on high alert after the attack on the convoy yesterday. (2)

10 Sep 1943
At 1014I/10, while patrolling of the Toagel Mlungui passage, USS Seahorse (T/Cdr. D. McGregor, USN) sighted the masts and funnel of a ship. An approach was started but on tracking the ship it became apparent that the ship was inside the lagoon and the approach was broken off.

At 1358I/10, in position 07°24'N, 134°16'E, to the south-west of the Toagel Mlungui passage, a convoy made up of two transports and a tanker were sighted. They were escorted by an armed merchant vessel, most likely and auxiliary gunboat. They were making for the Toagel Mlungui passage. An attack was started with the tanker as target. Due to the air escort it was decided to approach without using the periscope for a while. This was a costly mistake as after 13 minutes, during the next look it was seen that the convoy had made a zig away of about 55° and that the range had opened to 4200 yards. The attack was reluctantly broken off.

The ships sighted were most likely from convoy No. 2607 which had departed Balikpapan on 4 September.

This convoy was escorted by the destroyer Asakaze and auxiliary gunboat Manyo Maru (2904 GRT, built 1937). The convoy itself was made up of the transports Pacific Maru (5873 GRT, built 1920), Takaoka Maru (7047 GRT, built 1920), Yamayuri Maru (4910 GRT, built 1913), tankers Kyoei Maru (591 GRT, built 1937), Nissho Maru (10526 GRT, built 1938) and naval tanker Notoro. While en-route, on 8 September another destroyer [unidentified] and an auxiliary vessel had joined the convoy. The convoy arrived at Palau on 10 September. Most likely the convoy had split up before the ships were sighted by HMS Seahorse. (3)

11 Sep 1943
At 1112I/11, while patrolling of the Toagel Mlungui passage, USS Seahorse (T/Cdr. D. McGregor, USN) sighted an enemy patrol vessel.

As the three ships of the convoy that had been seen yesterday had all been laden Cdr. McGregor thought they might come out either today or tomorrow and would most likely turn northwards towards Japan. He had therefore positioned USS Seahorse in such a position as to intercept them.

At 1142I/11, when about 8 to 9 nautical miles to the north of the Toagel Mlungui passage a convoy made up of five ships and two escorts leaving the pass but instead of turning north the proceeded on course 280°. Commenced tracking them submerged being unable to attack.

At 1330I/11, an oiler, transport and an escort were sighted approaching from the south. They entered the Toagel Mlungui pass when the range was still 13000 yards. USS Seahorse meanwhile continued to track the convoy sighted earlier which was still proceeding westwards.

At 1715I/11, USS Seahorse surfaced and commenced an end around while keeping visual contact with the convoy. Had to dive twice for aircraft to avoid being sighted.

At 0300I/12, USS Seahorse submerged to approach the convoy. It was expected that 35 minnutes would be needed if the convoy continued on it's current course and speed. Nothing was however seen or heard from the convoy until .....

At 0410I/12, an escort started echo ranging close aboard while moving at slow speed. Nothing was seen as the weather and light conditions rendered periscope visibility almost zero.

At 0527I/12, USS Seahorse surfaced and continued tracking the convoy through frequent rain squalls.

At 0930I/12, contact was lost and course was set to return to the Toagel Mlungui passage. (2)

13 Sep 1943 (position 0.00, 0.00)
At 0844I/13, near the Toagel Mlungui passage, in position 07°29'N 134°18'E, USS Seahorse (T/Cdr. D. McGregor, USN) sighted a transport of about 3000 tons in ballast at a range of 10000 yards. Decided not to attack as the range could not be sufficiently closed to attack this small target in ballast.

At 1138I/13, an enemy patrol vessel was sighted. (2)

14 Sep 1943
USS Seahorse (T/Cdr. D. McGregor, USN) twice attacked a large, 10000 tons, tanker to the west of Babeldaob, Palau. A total of eight torpedoes were fired but no hits were obtained.

Perhaps this was the Nissho Maru (10526 GRT, built 1938) which departed Palau for Truk in a convoy on this day.

0610I/14 - In position 07°31'N, 134°18'E, near the Toagel Mlungui passage, USS Seahorse sighted a large tanker. Commenced an attack.

0627I/14 - Fired four stern torpedoes. Four depth charges were the response. The tanker was observed to have changed course from 060° to 130°. Four bow tubes were now made ready. Enemy course was 076°, speed 12 knots. Range was 2900 yards.

0643I/14 - Fired four bow torpedoes. One ran erratically. Again four more depth charges were the enemy response. These were spread out over 25 minutes preventing USS Seahorse from observing the results of the attack. When last seen the tanker was proceeding on course 130° at 120 RPM which would put him on the reef soon. It is not known if any hits were obtained but it was though to be highly probable. Enemy course was 128°, speed 12 knots. Range was 4200 yards. (3)

16 Sep 1943 (position 0.00, 0.00)
Around 2100I/16, USS Seahorse (T/Cdr. D. McGregor, USN) left patrol to proceed to Midway. (2)

27 Sep 1943
USS Seahorse (T/Cdr. D. McGregor, USN) ended her first, unsuccessful, war patrol at Midway. She was then taken in hand for repairs by the Submarine Base.

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