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Notable events involving Seahorse include:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

29 Jul 1943
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). (1)

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. (1)

17 Aug 1943
Around 1100I/17, USS Seahorse (T/Cdr. D. McGregor, USN) arrived in her patrol area. (1)

18 Aug 1943
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. (1)

22 Aug 1943
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. (1)

23 Aug 1943
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. (1)

24 Aug 1943
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. (1)

25 Aug 1943
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. (1)

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. (1)

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). (2)

31 Aug 1943
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. (1)

3 Sep 1943
USS Seahorse (T/Cdr. D. McGregor, USN) commenced to patrol off the Toagel Mlungui passage off the west coast of Babeldaob Island. (1)

4 Sep 1943
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. (1)

5 Sep 1943
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. (1)

6 Sep 1943
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. (2)

7 Sep 1943
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. (1)

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. (2)

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. (1)

13 Sep 1943
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. (1)

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. (2)

16 Sep 1943
Around 2100I/16, USS Seahorse (T/Cdr. D. McGregor, USN) left patrol to proceed to Midway. (1)

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.

13 Oct 1943
From 13 to 17 October 1943, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) conducted exercises off Midway.

20 Oct 1943
At 1500Y/20, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) left Midway for her 2nd war patrol. She was to patrol off South Honshu in Japanese home waters and in the East China Sea. (3)

29 Oct 1943
USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) claimed the sinking of a 200 tons Japanese trawler to the south-west of Aogashima, Izu Islands.

0830I/29 - In position 30°52'N, 138°41'E sighted a trawler.

0917I/29 - Dived and closed the track of the target.

1055I/29 - Surfaced and commenced and end around run on completion of which, dived.

1417I/29 - Battle surfaced in position 31°24'N, 138°24'E. Opened fire at a range of 2400 yards. The target made radical course changes and there were very few hits for the first 20 rounds of 4". In all 50 rounds of 4" were expended for 17 hits. The superstructure of the trawler was completely gone and she was on fire from stem to stern. Besides the 50 rounds of 4" also 150 rounds of 20mm and 300 rounds of .50 cal. machine gun rounds were used.

1505I/29 - Ceased fire.

1537I/29 - The target was seen to sink. Nine men were seen in the water.

2005I/29 - Entered the first patrol area. (3)

30 Oct 1943
USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) claimed the sinking of a 150 tons Japanese trawler well to the south of Wakayama Bay in position 30°48'N, 135°36'E.

0635I/30 - In position 30°48'N, 135°36'E sighted a trawler. Commenced to close to investigate.

0705I/30 - Dived and continued to close the target submerged.

1015I/30 - Surfaced to conduct high periscope patrol having decided to board the trawler at sunset.

1305I/30 - Dived with the target in sight. Carried out routines on the torpedoes.

1655I/30 - Battle surfaced at a range of 2500 yards and commenced to close the target. As it appeared the Japanese were preparing to repel a boarding party opened fire with the .50 cal machine gun. The first two rounds hit aft and the stern of the trawler soon went under. Fire was ceased when the Japanese had cleared to topside. A boarding party then went over in the rubber boat. They removed paperwork and charts as well as some gear and fresh fish. The trawler was then left in a sinking condition. The stern was under water to the aft part of the bridge and the trawler was still settling slowly. (3)

31 Oct 1943
USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) claimed the sinking of a 150 tons Japanese trawler well to the south of Shikuku.

1412I/31 - Sighted a trawler in position 31°19'N, 134°16'E. Closed to investigate.

1418I/31 - Dived and continued to close the target.

1722I/31 - Battle surfaced after sunset at a range of 740 yards. The trawler made an attempt to ram but shooting was excellend and the third round of 4" blew the bridge of the trawler completely off. Continued to fire until the trawler was a blazing shambles.

1750I/31 - The trawler was seen to sink. No survivors were seen. (3)

2 Nov 1943
USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) is credited to have sunk the Japanese troop transport Chihaya Maru and transport Yawata Maru out of a Japanese convoy. USS Seahorse also claimed to have sunk a large tanker but there was no tanker present in the convoy. [At least two of the transports in the convoy had their engines aft and thus may have been mistakenly identified as a tanker.]

The convoy attacked was convoy O-112 en-route from Saeki to Palau. It was made up of the transports Chihaya Maru (former Dutch Tjisaroea, 7089 GRT, built 1926), Delagoa Maru (7148 GRT, built 1919), Ehime Maru (4655 GRT, built 1920), Hozugawa Maru (1925 GRT, built 1941), Kanjo Maru (2186 GRT, built 1918), Moji Maru (3757 GRT, built 1922), Nichiai Maru (5443 GRT, built 1919), Tencho Maru (2716 GRT, built 1919), Ume Maru (5860 GRT, built 1919), Umekawa Maru (1931 GRT, built 1939), Yamagata Maru (3792 GRT, built 1916) and Yawata Maru (1852 GRT, built 1935).

The convoy was escorted by the minesweeper W-18, auxiliary submarine chasers Chiyo Maru No.8, Takunan Maru No.8 and the auxiliary minesweepers Aoi Maru, Takunan Maru No.3 and Tokuho Maru No.10.

It is possible more escorts were present. Most of the escorts apparently parted company during the night of 1/2 November. USS Seahorse reported seeing two 'Chidori-class' torpedo boats but the more modern Japanese W-class minesweepers looked very much like these torpedo boats so perhaps, besides W-18 another minesweeper was present.

2315I/31 - In position 31°48'N, 134°49'E obtained radar contact bearing 301° at a range of 16000 yards. Closed to investigate.

After four hours of tracking it was obvious that this was a large convoy. The radar operators were unable to keep contact on a single target but the course and speed of the convoy could non the less be determined.

0315I/1 - Dived ahead of the main body of the convoy at a range of 5000 yards, 2200 yards off track with the intention to get to the screen at radar depth and attack the main convoy with torpedoes.

During the approach a high, narrow black shape was seen close aboard and Seahorse had no other choice than to go deep and break off the approach. No A/S attack developed.

0405I/1 - Surfaced and commenced an end around run.

0505I/1 - Reached a position forward of the beam of the main body of the convoy. Dived as it was getting light. Ran in at high speed and by the time it was light enough to see well through the periscope Seahorse was in a good position to examine the entire convoy. 17 ships were in sight including escorts but there may have been more. Only the tops of the ships in the far column were visible and most likely the escorts beyond could not be seen. A 'Chidori-class' torpedo boat was on the port bow patrolling station with another 'Chidori-class' on the port beam. Patrol craft (PC's) were close to the main body of the convoy. A large tanker, passenger freighter and two large transports were in the lead.

0705I/1 - While waiting for the convoy to get clear distant depth charging commenced.

0900I/1 - Heard pinging. Sighted two 'Chidori-class' torpedo boats conducting a coordinated sound search of the area.

1030I/1 - Heard two distant depth charge explosions. The 'Chidori's' were both in sight with the closed one at 6000 yards. It was noticed that it were not the 'Chidori's' which were dropping depth charges.

1308I/1 - The 'Chidori's' were seen to join up and make off in the direction of the convoy at high speed.

1345I/1 - The 'Chidori's' were no longer in sight so surfaced and proceeded at maximum speed in the direction they made off.

1527I/1 - Sighted the tops of the 'Chidori's' and manoeuvred to keep them in sight. Their base course was about 180°.

1615I/1 - The 'Chidori's' both let out a puff of smoke and suddenly disappeared. Seahorse went to full speed on all four engines to follow them on course 180°.

2010I/1 - Obtained radar contact bearing 169° at 18000 yards. Commenced to work up to gain a position ahead of the convoy.

2200I/1 - In position 8000 yards on the starboard bow of the leading large ship when four orange flashes were seen in the rear of the convoy. Many distant depth charge explosions were heard and a searchlight display was witnessed by the bridge watch. It was obvious another American submarine must have made an attack [this was the work of USS Trigger (T/Lt.Cdr. R.E. Dornin, USN)]. Radar reported that the convoy was scattering and increasing speed.

Recommenced a night surface radar approach. Decided to attack a group of two large ships and three escorts. These escorts were very active and managed to be in the wrong place each time USS Seahorse started an attack run. After trying to attack from both beams finally reached an attack position on the port bow of a passenger freighter and at .....

0048I/2 - In position 28°37'N, 134°47'E, fired three bow torpedoes at the target from 3700 yards, the passenger freighter resembling the Hakone Maru of over 10000 tons. It was the intention to also fire three bow torpedoes at the other, leading, target, a freighter. The port escort however came directly towards at a range of 2100 yards and there was no more time to fire the remaining three bow torpedoes at the freighter. Immediately after firing radar range to the escort was only 1700 yards and he must have seen us. Three hits on the target were then observed and the stern was seen to break off. The stern was seen to sink immediately and the bow rose high in the air before it sank.

0114I/2 - Commenced investigating radar pips on several bearings at various ranges. While attempting to get into an attack position on a single large ship, and having great difficulty in getting past the escorts, the radar picked up two good pips at 10000 yards and target was shifted. This contact proved to be a large tanker and a relatively small freighter with two escorts well on the starboard side of the targets. Escorts and targets were proceeding on a course of 155°. It was very dark around this time and no difficulty was experienced to reach a good firing position.

0418I/2 - In position 28°37'N, 134°45'E, commenced firing three bow torpedoes at each of the targets from ranges of 2200 and 1700 yards. Pulled out to port and waited for hits. Two hits were observed on each target. One in the aft part of the tanker caused a violent explosion. The escorts closed rapidly and they closed to 1700 yards before range started to increase again. The tanker was closed to 300 yards before she stopped dead in the water settling by the stern.

0425I/2 - Radar reported one of the targets sinking at a range of 5000 yards. Changed course to close the remaining target to finish this ship off with a stern torpedo.

0426I/2 - One escort dropped a depth charge near the firing point while another escort was laying stopped near the point where the freighter had sunk. This escort was showing two bright green, all round, lights on his foremast.

0431I/2 - A violent explosion was observed in the tanker which caused her to burst into flames. The radar pip was decreasing and the tanker was seen to be low in the water.

0445I/2 - The tanker sank and it's radar pip disappered. Range was 8000 yards. The flames persisted indicating that oil on the water was on fire. There was still radar contact with the single target but it was not possible to reach an attack position before daylight.

0518I/2 - Dived. Depth charging continued until 0845I/2. The last ships were lost from sight at 1205I/2.

1323I/2 - Picked up HE of screws but could not see anything until .....

1403I/2 - A patrol craft (PC-type vessel) was seen approaching from the direction of the convoy.

1455I/2 - When the patrol craft was out of sight surfaced and went after the convoy with the hope of regaining contact.

0635I/3 - Not having obtained contact broke off the chase. (4)

4 Nov 1943
At 2242I/4, in position 29°50'N, 130°00'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) obtained radar contact at a range of 14000 yards. Three small pips were seen which looked like a convoy. The range was closed to 9000 yards when it was noticed that four ships were present making 9 knots on various courses. By the time the range had been closed to 7000 yards the ships were identified as patrol vessels. They were evaded. (3)

6 Nov 1943
At 0823I/6, in position 31°08'N, 128°00'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a fishing sampan which was avoided. (3)

8 Nov 1943
At 0730I/8, in position 32°18'N, 126°56'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a lighted fishing sampan which was avoided.

At 1251I/8, in position 31°44'N, 127°14'E, two fishing sampans were sighted which were avoided. (3)

9 Nov 1943
At 0040I/9, in position 31°38'N, 128°07'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted four lighted fishing sampans which were avoided. (3)

10 Nov 1943
At 1225I/10, in position 32°15'N, 128°15'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted two fishing large trawlers which were avoided. (3)

11 Nov 1943
At 0236H/11, in position 32°20'N, 127°32'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a fishing sampan which was avoided.

At 0845H/11, in position 32°08'N, 126°51'E, USS Seahorse sighted a fishing sampan which was avoided.

At 1347H/11, in position 32°14'N, 127°04'E, USS Seahorse sighted a fishing sampan which was avoided.

At 1915H/11, in position 32°15'N, 127°05'E, USS Seahorse sighted a lighted fishing sampan which was avoided. (3)

12 Nov 1943
At 1441H/12, in position 32°17'N, 127°11'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a fishing sampan which was avoided.

At 1825H/12, in position 32°14'N, 126°54'E, USS Seahorse sighted a lighted fishing sampan which was avoided. (3)

13 Nov 1943
At 0132H/13, in position 33°16'N, 127°30'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted an enemy patrol vessel which was avoided. This patrol vessel produced quite a lot of smoke.

At 1730H/13, in position 33°50'N, 127°29'E, USS Seahorse sighted smoke bearing 210°. Distance was estimated to be about 15 nautical miles.

At 1745H/13, USS Seahorse surfaced and proceeded on course 120° to head off the target.

At 1858H/13, course was altered to 180° but the target was not sighted.

At 1952H/13, in position 33°31'N, 128°16'E, smoke was sighted bearing 130°. Changed course and went to full speed to head off the target.

At 2003H/13, radar picked up the target at 18000 yards. Course of the target was 100° at 14 knots. An escort was sighted on the port beam of the target. USS Seahorse commenced an end around to get ahead of the target.

At 2130H/13, the end around was abandoned as it would be impossible to get ahead of the target before it would enter coastal waters. It was thought the target was a fairly large ship. (3)

14 Nov 1943
At 0200H/14, in position 33°21'N, 127°38'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted an enemy patrol vessel which was avoided.

At 1125H/14, in position 33°03'N, 126°56'E, USS Seahorse sighted a fishing sampan which was avoided. (3)

15 Nov 1943
At 0928H/15, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a ship bearing 185° at a range of 7000 yards. Fog was just lifting at that moment. Target course was estimates as being 090° at just 3 knots.

At 1000H/15, when visibility had improved further and the range had been closed to 4000 yards it was seen that the target was aground, high and dry on a reef in position 33°31'N, 126°58'E. No further action was needed as the ship was clearly beyond salvage. (3)

16 Nov 1943
At 0047H/16, in position 32°30'N, 128°21'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a lighted fishing sampan which was avoided. (3)

17 Nov 1943
At 0136H/17, in position 32°16'N, 129°15'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted smoke bearing 144°.

By 0140H/17, it was determined that the source(s) of the smoke was making for Nagasaki, proceeding on course 050°. Increased speed to 17 knots to close the target.

At 0145H/17, USS Seahorse altered course to 115° and increased speed to the maximum to get ahead of the targets as it was soon seen that it was a convoy of two transports and two escorts.

At 0219H/17, radar had not been working properly and contact was now lost on one of the escorts. This was soon seen from the bridge to be a destroyer which was coming directly towards at high speed. USS Seahorse turned stern on when the range was 5500 yards. The range kept closing rapidly so USS Seahorse dived. The convoy meanwhile had changed course. The destroyer was hunting overhead with frequent course and speed changes made it impossible to attack her with torpedoes. The destroyer made several dummy attack runs but at .....

0329H/17, dropped a pattern of seven depth charges but they were not close. Only some cork and paint came off.

0406H/17, the destroyer was still in contact despite frequent depth changes by USS Seahorse which set a course to clear the area to the south-west.

0421H/17, the destroyer dropped four depth charges after several practice runs. They exploded very close. The submarine was shaken very severely and some light bulbs were broken but no serious damage was sustained. USS Seahorse went to full speed and made a radical course change and the destroyer lost contact.

0630H/17, the destroyers screws faded out.

0710H/17, heard to distant depth charge explosions.

0755H/17, saw an aircraft circling the destroyer which was now also seen to be closing again.

0840H/17, the destroyer passed close aboard but she did not gain contact though definitely hunting.

1410H/17, the destroyer cleared the area.

1810H/17, now surfaced radar contact was obtained on what is thought to be a patrol vessel steering courses between 070° and 250°. This was avoided. Position was 31°53'N, 128°54'E. (3)

19 Nov 1943
At 1010H/19, while on the surface in position 31°14'N, 128°56'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a plane coming out of low cloud at a short distance. Crash dived.

At 1011H/19, the aircraft, a two engine float plane, dropped two bombs that well aimed and some minor damage was caused.

USS Seahorse patrolled submerged for the remainder of the day during daylight surfacing at 1755H/19. (3)

21 Nov 1943
At 0844H/21, a two-masted sailing vessel was sighted by USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) in position 34°09'N, 127°50'E. It was avoided.

At 0857H/21, another two-masted sailing vessel was sighted in position 34°06'N, 127°49'E. It too was avoided.

At 1609H/21, in position 34°18'N, 127°47'E, smoke was sighted which was drawing right. Range was estimated as being 15000 yards. Course was set to close.

By 1835H/21, it was apparent, through tracking, that the contcat must be a very small vessel and the approach was broken off in position 34°24'N, 128°04'E. (3)

22 Nov 1943
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese transport Daishu Maru (3099 GRT, built 1919) out of a convoy in the East China Sea west of the Tsushima Strait in position 33°41'N, 128°35'E.

0117H/22 - In position 33°39'N, 128°42'E sighted smoke and immediately commenced to close. The contact developed into a convoy made up of three small transports and two destroyers.

0208H/22 - Dived 2700 yards of the convoys track. Range to the leading transport was 12000 yards. A quick plot put the convoy on course 105° at 9 knots. USS Seahorse ran at radar depth but the radar failed to give results until the range had closed to 2200 yards. When the range was 1830 yards on the largest ship came to periscope depth to complete the attack.

0245H/22 - in position 33°36'N, 128°35'E, commenced firing four torpedoes at transport of around 4000 tons from 1500 yards. Two hits were obtained. The target was seen to be obscured by smoke but USS Seahorse had go deep as the destroyers were rapidly closing.

0329H/22 - Seven extremely heavy depth charges exploded but not close. The destroyers were not in contact.

0405H/22 - Six more depth charges exploded. USS Seahorse was now at periscope depth but nothing could be seen.

0418H/22 - Surfaced. A destroyer was seen milling around on the port quarter. The enemy was put stern on and USS Seahorse retired at full speed. (3)

24 Nov 1943
At 2352H/24, in position 31°27'N 128°02'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a lighted fishing sampan which was avoided. (3)

25 Nov 1943
At 0005H/25, in position 31°27'N 128°01'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a lighted fishing sampan which was avoided.

At 0032H/25, in position 31°25'N 127°52'E, USS Seahorse sighted a lighted large trawler which was avoided.

At 0718H/25, in position 30°38'N 127°21'E, USS Seahorse sighted a fishing sampan which was avoided. (3)

26 Nov 1943
At 0916H/26, in position 33°24'N 127°27'E, USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) sighted a fishing sampan which was avoided. (3)

27 Nov 1943
USS Seahorse (T/Lt.Cdr. S.D. Cutter, USN) attacked a convoy and torpedoed and sank the Japanese tanker San Ramon Maruaa (7309 GRT, built 1935) in the East China Sea in position 33°36'N, 128°57'E.

Lt.Cdr. Cutter claimed to have sunk a second large tanker but this claim could not be confirmed post war.

1045H/26 - Sighted smoke bearing 295°.

1315H/26 - Heard echo ranging bearing 305°. No ships were in sight but three sources of smoke were visible.

1416H/26 - Sighted a two-engined bomber patrolling over the convoy. There were still no ships in sight. Lt.Cdr. Cutter decided to run submerged parallel to the convoy during daylight hours and then surface after sunset to attack the convoy on the surface.

1720H/26 - Surfaced and set off in pursuit of the convoy.

1755H/26 - Obtained radar contact bearing 083° at a range of 19900 yards.

1823H/26 - Sighted large ships. Commenced tracking them with radar. Base course of the convoy was 100° at 10 knots. The convoy was seen to be made up of two large tankers and three escorts.

12 Dec 1943
USS Seahorse (Lt.Cdr. S.D. Cutter) ended a successful 2nd war patrol at Pearl Harbor.

6 Jan 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) left Pearl Harbor for her 3th war patrol. She was to patrol off the Palau Islands.

16 Jan 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese merchant Nikko Maru (784 GRT) south-east of the Mariana Islands in position 12°49'N, 150°19'E.

21 Jan 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese troop transport Ikoma Maru (3156 GRT) and transport ship Yasukuni Maru (3021 GRT) about 280 nautical miles east-south-east of Palau in position 03°19'N, 137°02'E.

30 Jan 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese transport ship Toko Maru (2747 GRT) south-east of Palau in position 06°10'N, 138°14'E.

1 Feb 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese troop transport Toei Maru (4004 GRT) about 175 nautical miles south of Woleai in position 04°24'N, 143°15'E.

16 Feb 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) ended her very successful 3th war patrol when she returned to base at Pearl Harbor.

16 Mar 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) left Pearl Harbor for her 4th war patrol. She was to patrol in the Mariana Islands area.

8 Apr 1944
USS Seahorse (Lt.Cdr. Slade Deville Cutter) torpedoed the Japanese munitions transport Aratama Maru (6783 GRT) and damaged the water carrier Kizugawa Maru (1915 GRT) off Guam in position 13°16'N, 145°11'E. The explosion on Aratama Maru damaged the Japanese destroyer Asakaze (offsite link). The burning Aratama Maru is beached but explodes and sank the next day. The damaged Kizugawa Maru is towed to port by the Japanese destroyer Minazuki (offsite link).

9 Apr 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese troop transport Misaku Maru (4667 GRT) about 40 nautical miles west of Saipan in position 15°32'N, 145°00'E.

20 Apr 1944
There is a claim that USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese submarine RO-45 (offsite link) off the Mariana Islands in position 15°19'N, 145°31'E. But according to the combinedfleet.com website this is not the case as RO-45 was active after this date.

27 Apr 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese troop transport Akikawa Maru (5244 GRT) about 150 nautical miles west of Saipan in position 14°46'N, 143°22'E.

11 May 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) ended her 4th war patrol at Brisbane, Australia.

11 Jun 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) leaves Brisbane, Australia for her 5th war patrol. She was ordered to patrol in the Luzon Strait between Formosa and Luzon.

27 Jun 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese tanker Medan Maru (5135 GRT) south-south-west of Formosa in position 21°10'N, 120°31'E.

3 Jul 1944
During the night of 3 / 4 July 1944 USS Seahorse (Lt.Cdr. S.D. Cutter) torpedoed and sank the Japanese merchants Gyoyu Maru (2232 GRT), Niito Maru (2186 GRT) and Kyodo Maru No.28 (1518 GRT) in the South China Sea about 140 nautical miles south of Hong Kong in position 20°18'N, 115°02'E.

19 Jul 1944
USS Seahorse (Lt.Cdr. S.D. Cutter) ended her 5th war patrol at Pearl Harbor.

10 Aug 1944
During 10/11 August 1944, USS Skipjack (T/Cdr. R.S. Andrews, USN) and USS Searaven (T/Cdr. M.H. Dry, USN) conducted exercises off Pearl Harbour with USS Burden R. Hastings (Lt.Cdr. E.B. Fay, USNR).

Later USS Seahorse (T/Capt. C.W. Wilkins, USN) and USS Allen (Lt. W.J. Riley, Jr., USNR) before the night exercises commenced.

On the 11th, USS Greiner (T/Lt.Cdr. L.H. Kiser, USN) also joined. (5)

6 Oct 1944
While on her 6th war patrol USS Seahorse (Lt.Cdr. Charles Warren Wilkins) torpedoed and sank the Japanese Coast Defense Vessel Kaibokan 21 (745 tons, offsite link) about 140 nautical miles North-West of Cape Bojeador, Luzon in position 19°27'N, 118°08'E.

18 Oct 1944
USS Seahorse (Lt.Cdr. C.W. Wilkins) ended her 6th war patrol at Midway. She was ordered to the Mare Island Navy Yard for overhaul.

5 Mar 1945
USS Bullhead (Cdr. W.T. Griffith, USN) conducted exercises off Pearl Harbour together with USS Pruitt (Lt. D.B. Harby, USNR), USS YMS-300 (Lt. R.A. Woods, USNR) and USS Seahorse (Cdr. H.H. Greer, Jr., USN).

9 Mar 1945
USS Seahorse (Cmdr Harry Holt Greer, Jr.) left base for her 7th war patrol, and was ordered to patrol the Tsushima Strait.

9 Apr 1945
USS Seahorse (Cdr. H.H. Greer, Jr) sank a small junk with gunfire in position 33°20'N, 127°36'E.

18 Apr 1945
USS Seahorse (Cdr. H.H. Greer, Jr) is damaged by depth charges in Tsushima Strait in position 33°45'N, 128°26'E and is forced to terminate her patrol.

12 Jul 1945
After repairs and overhaul USS Seahorse (Cdr. H.H. Greer, Jr) left Pearl Harbor for her 8th war patrol. She was to patrol of the Izu Islands, Japan. When the war ended on 15 August 1945 Seahorse was on patrol 40 miles southeast of Hachijo Shima. She returned to Midway in the latter half of August.

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