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Submarine HNMS O 23 (P 23)

28 Sep 1940
Lt.Cdr. A.M. Valkenburg, RNN, temporary took over command of HrMs O 23 from Lt.Cdr. G.B.M. van Erkel due to the last one being sick. (1)

5 Oct 1940
Around 1400A/5, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Dundee for her 3rd war patrol. She was ordered to patrol off the south-west coast of Norway near Bergen.

For the daily positions of HrMs O 23 during this patrol see the map below.

(2)

9 Oct 1940 (position 60.32, 4.01)
At 0500A/9, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN), grounded at 70 feet near position 60°32'N, 04°01'E. She immediately surfaced and it was noticed that she was much nearer to the coast then thought being offset due to the strong current. She dived again and remained close inshore during the day. No major damage was caused to the submarine during the grounding though. (2)

14 Oct 1940 (position 0.00, 0.00)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was followed in her movements for about an hours by what is thought to be an enemy A/S trawler. This trawler then kept patrolling in practically the same spot the entire day. A black buoy was also seen in the area which may have been dropped by this vessel. (2)

15 Oct 1940 (position 0.00, 0.00)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was again followed in her movements for about 2.5 hours by what is thought to be an enemy A/S vessel. (2)

16 Oct 1940 (position 0.00, 0.00)
In the afternoon, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a trawler close to Fedjeosen, to the north of Bergen. (2)

18 Oct 1940 (position 0.00, 0.00)
Around 1800A/18, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) left patrol to return to Dundee. (2)

20 Oct 1940
Around 1400A/20, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 3rd war patrol at Dundee. (2)

21 Oct 1940 (position 0.00, 0.00)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is wiped (degaussed) at Dundee. (3)

31 Oct 1940 (position 0.00, 0.00)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted compass adjustment trials at Dundee. (3)

4 Nov 1940
Around 1300A/4, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Dundee for her 4th war patrol. She was ordered to patrol off the south-west coast of Norway near Bergen.

On departure some independent exercises were carried out near Bell Rock until around 1800A/4.

For the daily positions of HrMs O 23 during this patrol see the map below.

(2)

6 Nov 1940
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was ordered, in the Vice Admiral Submarines signal timed 1218A/6, to patrol slightly further to the south then in her original orders. She is now to patrol near position 60°00'N, 03°20'E. (2)

7 Nov 1940
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was ordered to patrol even further to the south off Stavanger, Norway. (59°00'N, 03°50'E). (2)

13 Nov 1940
Between 1923A/13 and 1930A/13, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) heard the sound of explosions. On surfacing at 1949A/13 a fire was seen bearing 130°. It was also thought that a ship was seen. O 23 dived until 2010A/13 but nothing further was observed.

HrMs O 23 was also ordered to patrol a little further to the south, off Obrestadt, Norway in position 58°31'N, 05°25'E. (Vice Admiral Submarines signal timed 1852A/13) (2)

15 Nov 1940
At 1045A/15, when in approximate position 58°40'N, 05°18'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a northbound merchant vessel close inshore. The range could not be closed sufficiently in time to attack.

This may have been the German merchant vessel Bahia (4117 GRT, built 1927) which had departed Kristiansand around 1020B/14 for Haugesund where she arrived around 1700A/15. She was escorted by the auxiliary M/S trawler M 1104 / Jan Hubert (460 GRT, built 1937).

At 2050A/15, in approximate position 58°36'N, 05°20'E, HrMs O 23 sighted three ships bearing 145°. Commenced attack on what was thought to be a northbound convoy.

At 2107A/15, the attack was broken off and O 23 turned away at high speed. It had been seen that the ships were all trawlers, thought to be auxiliary A/S vessels.

The German auxiliary A/S trawler UJ 177 / Nordmeer (465 GRT, built 1938) and the German auxiliary M/S trawler M 1107 / Carl Stangen (433 GRT, built 1937) were on patrol between the Feistein Lighthouse and Egersund and may have been the ships sighted. (4)

16 Nov 1940
At 1245A/16, in approximate position 58°35'N, 05°24'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a merchant vessel in ballast and a tug which was possibly towing the merchant vessel. They were south bound and were escorted by three A/S trawlers. It was not possible to attack as the range was too great and they were already too far ahead.

This must have been the damaged German merchant vessel Barenfels (7569 GRT, built 1921) being towed by the tugs Taifun (276 GRT, built 1937), Seefalke (570 GRT, built 1924) and the auxiliary patrol vessel V 5107 / Sturm (151 GRT, built 1938). On departure from Stavanger (for Kristiansand) around 0920B/16, they were escorted by the A/S trawlers UJ 176 / Danzig (476 GRT, built 1937), UJ 178 / Faröer (470 GRT, built 1937), UJ 179 / Carl Kampf (600 GRT, built 1940) and the auxiliary patrol vessel V 5103 / Orkan (?). (5)

17 Nov 1940 (position 0.00, 0.00)
Around 1900A/17, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) left patrol to return to Dundee. (2)

19 Nov 1940
Around 1100A/19, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 4th war patrol at Dundee. (2)

20 Nov 1940
Now off the sick list, Lt.Cdr. G.B.M. van Erkel, again takes up command of HrMs O 23. (6)

30 Dec 1941
During her refit at Dundee by the Caledon Dockyard, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is docked again. This time in the East Graving Dock. (7)

4 Jan 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is undocked. She continued her refit at Dundee by the Caledon Dockyard. (7)

8 Feb 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted post refit trials on the river Tay near Broughtly Ferry. (7)

11 Feb 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted post refit trials on the river Tay near Broughtly Ferry. (7)

12 Feb 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted post refit trials on the river Tay near Broughtly Ferry. (7)

14 Feb 1942
From 14 to 17 February, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted more post refit trials in the Tay and Forth river sanctuaries. (7)

22 Feb 1942
With her initial post refit trials completed, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN), departed Dundee aroud 0800A/22 for Holy Loch for a period of training. During the passage she is escorted by the A/S trawler HMS Quadrille (T/Lt. N.T. Chetwood, RNVR). (7)

24 Feb 1942
Around 2300A/24, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrives at Holy Loch where she begins a period of training. (7)

27 Feb 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted special torpedo firing trials with captured German torpedoes off Arrochar. (7)

28 Feb 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted special torpedo firing trials with captured German torpedoes off Arrochar. Upon completion of these O 23 proceeded to Holy Loch. (7)

2 Mar 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted noise trails in Loch Goil. (7)

3 Mar 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted exercises in the Clyde area. (7)

4 Mar 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted speed trails on the measured mile in Loch Long. (7)

10 Mar 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted D/G trials off Helensburgh. (7)

11 Mar 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted exercises in the Clyde area. (7)

12 Mar 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack exercises in the Clyde area. The target was HMS Adamant (Capt. R.S. Warne, RN) which was escorted by HMS Breda (Capt.(Retd.) A. E. Johnston, RN) and HMS Z 5 (T/A/Lt.Cdr. S.T. Wenlock, RNR).

Following these exercises more attack exercises were carried out during the night with HMS Z 5. (7)

13 Mar 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) returned to Holy Loch on completion of last night's exercises. (7)

16 Mar 1942
After a rather short working up period, around 1015A/16, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Holy Loch for the Far East. The fist leg of this passage is to Gibraltar. O 23 is escorted by the destroyer HMS Vimy (Lt.Cdr. H.G.D. de Chair, RN) that is en-route to Portsmouth for a refit. Also in company was HMS Sturgeon (Lt.Cdr. M.R.G. Wingfield, RN) that was en-route to Plymouth before departing on a war patrol in the Bay of Biscay.

During the passage through the Irish Sea extreme thick fog is encountered and the ships were delayed as they had to anchor because of the low visibility. As O 23 loses her anchor early on the 18th all three ships made for Milford Haven where the anchor of O 23 is inspected before proceeding after a few hours.

Around 0300A/19, O 23 parted company to proceed to Gibraltar independently. (7)

16 Mar 1942 (position 0.00, 0.00)
For the daily positions of HrMs O 23 during the passage from the U.K. to Ceylon see the map below.

24 Mar 1942
Around 1300A/24, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Gibraltar. She had been escorted in by a [so far unidentified] corvette. (7)

28 Mar 1942
Around 1700A/28, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Gibraltar for Alexandria. (7)

30 Mar 1942 (position 0.00, 0.00)
Around 1115A/30, well north of Algiers, in approximate position 38°28'N, 03°06'E, the submerged HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was passed by the northbound Vichy French merchant vessel Oued Tiflet (1190 GRT, built 1914). (7)

1 Apr 1942 (position 38.29, 7.40)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) encounters a submarine south-west of Sardinia, Italy near position 38°29'N, 07°40'E. Before an attack could be started the other submarine submerged. O 23 did the same and for an hour she hunted the other submarine but no contact could be made.

The other submarine was the Italian Aradam that dived immediately upon seeing another submarine as it was not certain if it was a friendly or an enemy submarine.

0045A/1 - Near position 38°29'N, 07°40'E sighted a submarine bearing 240°. The course of the other submarine was 340°. Closed on the surface.

0052A/1 - The other submarine dived.

0054A/1 - O 23 also dived and obtained contact with the hydrophones but no definite bearing or range could be obtained.

0156A/1 - O 23 surfaced and continued her passage towards Alexandria. (7)

2 Apr 1942 (position 0.00, 0.00)
Around 0900A/2, to the south-east of Marettimo Island, in approximate position 37°42'N, 12°15'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighed what is thought to be an enemy minesweeper proceeding in the direction of Pantelleria Island. The enemy passed the submerged submarine at a range of 500 yards. (7)

9 Apr 1942
Around 0915C/9, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Alexandria. The onward passage to the Far East had to be delayed as O 23 had to be docked for repairs. (7)

23 Apr 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is docked in the Gabbari graving dock at Alexandria. (7)

24 Apr 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is undocked. (7)

25 Apr 1942
Around 1000C/25, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Alexandria for Port Said. (7)

26 Apr 1942
Around 1030C/26, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) passed the boom at Port Said and then immediately entered the Suez Canal for the southbound passage. (7)

1 May 1942
Around 0800C/1, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Aden from Alexandria. (7)

2 May 1942
Around 0800C/2, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Aden for Colombo. (7)

9 May 1942
Around 0930F/9, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Colombo from Aden. (7)

13 May 1942
For the daily positions of HrMs O 23 during the passage from Colombo to Bombay see the map below.

(7)

16 May 1942
Upon arrival at Bombay, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is taken in hand for repairs at the Bombay Dockyard. (7)

3 Jul 1942
With her repairs completed, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted post repair trials off Bombay. (8)

5 Jul 1942
Around 1200F/5 HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) and HrMs K XIV (Lt. J.H. Geijs, RNN) departed Bombay for Colombo. They were escorted by the minesweeper HMAS Lismore (Lt.Cdr. S.H. Crawford, RANR(S)).

Because of defects HrMs K XIV returned to Bombay the next day.

For the daily positions of HrMs O 23 during this passage see the map below.

(8)

9 Jul 1942
Around 1300F/9, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) and her escort, HMAS Lismore (Lt.Cdr. S.H. Crawford, RANR(S)) arrived at Colombo from Bombay. (8)

14 Jul 1942
Off Colombo, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) carries out practice attacks on and A/S exercises with the sloops HMS Falmouth (Cdr. U.H.R. James, RN) and HMS Shoreham (Cdr. E. Hewitt, RD, RNR). (8)

15 Jul 1942
Off Colombo, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) carries out practice attacks on and A/S exercises with the sloops HMS Falmouth (Cdr. U.H.R. James, RN) and HMS Shoreham (Cdr. E. Hewitt, RD, RNR). (8)

19 Jul 1942
Around 1730F/19, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for her 14th war patrol (1st in the Far East). She was ordered to patrol in the Malacca Staits.

For the daily and attack positions of HrMs O 23 during this patrol see the map below.

(2)

27 Jul 1942 (position 5.07, 98.50)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) damaged the small Japanese merchant vessel Shofuku Maru No.2 (729 GRT, built 1937) with gunfire about 10 nautical miles south-west of Penang, Malaya in position 05°07'N, 100°04'E. Two torpedoes had been fired first but both had missed.

0641F/27 - Sighted a ship bearing 190°, range 5 nautical miles. The ship was steering North. Started attack. When the ship came closer it was seen to be a small coastal vessel of about 800 to 1000 tons.

0725F/27 - In position 05°07'N, 100°04'E fired two torpedoes from 700 yards. One of the torpedoes was sene to run on the surface several times and to run slightly to Starboard. Both torpedoes missed.

0731F/27 - Surfaced behind the target to attack it with gunfire.

0732F/27 - Fired the first shot from 800 yards. The target was not armed.

0739F/27 - When the 10th round was being loaded in the gun it jammed and could not be freed so gunfire had to be discontinued. By now one hit on the ships stern had been obtained.

0741F/27 - Opened fire with the Oerlikon. but this too jammed after 80 rounds. Several hits had been observed. The action had now to be broken off. Withdrew to seaward. (2)

29 Jul 1942 (position 5.37, 98.50)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) fired four torpedoes at the Japanese heavy cruisers Kumano and Suzuya escorted by the destroyers Oyashio, Hayashio and Kuroshio (all offsite links) in the Malacca Straits about 10 nautical miles west-south-west of Pulau Perak in position 05°37'N, 98°50'E. The torpedoes missed their targets and O 23 was depth charged for several hours but eventually managed to escape without damage.

0525F/29 - Sighted two cruisers thought to be of the Takao-class (but later thought to be Mogami-class, and this was correct) and four destroyers bearing 185°, distance 7 nautical miles. Enemy course was 325°. Started attack altough a favourable attack position most likely could not be obtained.

After a few minutes the enemy ships had altered course towards on a zig-zag. Unfortunately this course was only steered for a very short time. Range could not be closed further then 5500 yards.

0600F/29 - In position 05°37'N, 98°50'E fired four torpedoes from 5500 yards. No torpedo explosions were heard.

0612F/29 - Heard two explosions thought to be depth charges. Upon returning to periscope depth one cruiser and one destroyer were seen to have altered towards. Lt.Cdr. Valkenburg quickly set up an attack with the stern torpedo tubes but before these could be fired depth control was lost and O 23 went to a greater depth. In the meantime several depth charges were dropped.

0848F/29 - After having heard no HE for half an hour returned to periscope depth. One destroyer was seen bearing 310°, distance 4 nautical miles. She appeared to be searching for the attacking submarine. O 23 retired in the opposite direction.

1043F/29 - Returned to periscope depth to have another look. Two destroyers and two submarine chasers were seen half a mile ahead. Lt.Cdr. Valkenburg took evasive action and went deep again.

1200F/29 - Returned to periscope depth to hsve another look. Nothing in sight.

During the evening two patrolling destroyers were evaded twice. (2)

2 Aug 1942 (position 5.36, 99.48)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) attacked a Japanese convoy and torpedoed and heavily damaged the Japanese army cargo ship Zenyo Maru (6440 GRT, built 1937, offsite link) about 30 nautical miles north-west of Penang, Malaya in position 05°36'N, 99°48'E. The Japanese ship burns out and was later towed to Singapore. She was declared a total loss and subsequently scrapped.

[We have so far been unable to identify the other ships in the convoy.]

0840F/2 - Sighted a convoy made up of one armed merchant with guns forward and aft that was acting as escort. This ship was followed by four merchant vessels. Started attack.

0926F/2 - In position 05°33'N, 99°48'E fired one torpedo on the first merchant ship behind the escort from 800 yards. Unfortunately the torpedo ran straight to the bottom and detonated 7 seconds after firing. No damage was caused to O 23. After this explosion the escort immediately turned away followed by the first merchant ship.

0930F/2 - The second merchant ship however waited several minutes so this was fired upon with two torpedoes from the training torpedo tubes. Range was 900 yards. Two faint explosions were heard 50 and 60 seconds after firing which was the correct running range.

0935F/2 - Two stern torpedoes were fired on the last ship from 1000 yards. A huge explosion occured amidships on thuis ship 60 seconds after firing. This ship was at once full ablaze. The other ships were now seen to have turned to the North. Depth charges were dropped at irregular intervals most likely by the escort.

As the ship that was hit did not appeared to be sinking it was decided to finish it off with the deck gun. However the escort turned back and dropped depth charges, some of which were quite close. The gun attack was abandoned and O 23 went deep and cleared the area. (2)

3 Aug 1942 (position 0.00, 0.00)
At 2230F/3, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) left her patrol area in accordance with the instructions given in the Senior Officer Submarines Ceylon signal timed 1041F/30. (2)

4 Aug 1942 (position 0.00, 0.00)
At 0432F/4, north-east of Diamond Head, Sumatra, in approximate position 05°42'N, 97°12'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighed a ship bearing 284°, range 3 to 4 nautical miles.

The subsequent change of the bearing seemed to indicate that this ship was proceeding eastwards. The ship looked like a small destroyer.

At 0440F/4, O 23 dived but three minutes later the forward hydroplanes jammed and could not be elevated. O 23 was able to remain at 75 feet and three minutes later hydroplane control was changed to hand gear. Hydrophones meanwhile indicated that the enemy vessel was very close.

0505F/4, O 23 returned to periscope depth. The enemy ship was seen bearing 100°, range 3 nautical miles. Again it was thought that the enemy was a small destroyer or minesweeper. Engine sound indicated it was most likely a minesweeper with a triple expansion engine. (2)

5 Aug 1942 (position 0.00, 0.00)
During the day, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) made a periscope reconnaissance of Sabang Bay. (2)

10 Aug 1942
Around 0810F/10, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 14th war patrol (1st in the Far East) at Colombo. (2)

24 Aug 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is docked in the inner graving dock at Colombo. (9)

29 Aug 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is undocked following which she conducted post repair trials off Colombo during which is was found that the amidships 'deck' torpedo tubes were leaking. Before leaving on patrol repairs were made. (9)

1 Sep 1942
Around 1700FG/1, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for her 15th war patrol (2nd in the Far East). She was ordered to patrol in the Andaman Sea, Malacca Staits and North-West coast of Sumatra.

For the daily and attack positions of HrMs O 23 during this patrol see the map below.

(2)

9 Sep 1942 (position 7.30, 98.03)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) made a torpedo attack on a Japanese merchant vessel about 40 nautical miles south-west of Phuket in position 07°30'N, 98°03'E. Two torpedoes were fired but both missed their target. The enemy ship was armed and around 3000 to 4000 tons. [We have so far been unable to identify this enemy vessel.]

0900FG/9 - Heard HE bearing 300° but nothing could be seen in that direction due to heavy rain squalls.

09100900FG/9 - Sighted, for a very short moment, a merchant ship bearing 292°, distance 4 nautical miles. Started attack. The ship was later seen to be of about 3000 to 4000 tons and was armed with a gun forward and aft. Decided to attack dispite a minumum chance of succes owning to the possible bad depth keeping of the torpedoes in the bad weather.

09450900FG/9 - In position 07°30'N, 98°03'E fired two torpedoes from 1700 yards. Two detonations were heard 6 and 7.5 minutes after firing the first torpedo. These were end of run detonations. After the first explosion the target made off to the south in a direction of 150° and started zig-zagging. (2)

13 Sep 1942 (position 0.00, 0.00)
At 1500FG/13, north-east of Sabang, in approximate position 06°01'N, 95°12'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a small merchant ship of about 2000 tons bearing 040° at a range of about 3.5 to 4 nautical miles. Course of the enemy was about 330° at 10 knots. O 23 altered course to the north but the chase soon had to be abandoned. (2)

14 Sep 1942 (position 0.00, 0.00)
At 1904FG/14, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) surfaced in approximate position 04°09'N, 95°50'E, after a day of submerged patrol. She then left patrol to return to Colombo. (2)

19 Sep 1942
Around 1115FG/19, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 15th war patrol (2nd in the Far East) at Colombo. (2)

13 Oct 1942 (position 0.00, 0.00)
Around 1820FG/13, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) for an engine trial run to the Gulf of Mannar and then back to Colombo. (9)

15 Oct 1942 (position 0.00, 0.00)
Around 1145FG/15, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) returned to Colombo from her diesel engines trial run to the Gulf of Mannar. (9)

17 Oct 1942
Around 1800FG/17, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for her 16th war patrol (3rd in the Far East). She was ordered to patrol in the Malacca Staits.

For the daily and attack positions of HrMs O 23 during this patrol see the map below.

(2)

25 Oct 1942 (position 5.28, 99.56)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) torpedoed and damaged the Japanese merchant vessel Shinyu Maru (4622 GRT, built 1919) off Penang, Malaya in position 05°28'N, 99°56'E.

0840FG/25 - Sighted smoke bearing 158°.

0850FG/25 - Sighted what is thought to be a ship bearing 163°, distance about 15 nautical miles. The ships course appeared to be south-west.

0905FG/25 - Sighted smoke bearing 170°. This smoke appeared to be from four ships, distance about 15 nautical miles, they were also on a south-westerly course. These ships were all merchant vessels of about 5000 tons. It was later seen that an A/S trawler was also in the area.

1118FG/25 - Initially thought they were heading toward Rangoon but at a signal from the trawler all ships set course for the northern entrance to Penang. Started attack.

1145FG/25 - In position 05°34'N, 99°54'E fired two bow torpedoes at the first ship of the convoy behind the A/S trawler. Range was 1300 yards. One hit was observed just before the bridge. The ship was seen to list to port and also to turn round to port. Immediately after firing the second torpedo Lt.Cdr. Valkenburg turned O 23 to attack the second ship line with the two remaining bow torpedoes. It was his intention to attack the third ship with the two torpedoes in the training (deck) torpedo tubes and the fourth ship with the two torpedoes in the stern torpedo tubes.

1147FG/25 - Fired two bow torpedoes at the second ship in line. Range was also 1300 yards. Immediately after firing the first torpedo the first ship in line was hit by the first salvo. This resulted in the second ship altering course and increasing speed so both torpedoes missed. As the third and fourth ship also altered course the attack on them was abandoned. The convoy now fled to seaward and was later seen to make a detour to the north before entering Penang.

1151FG/25 - Fired one torpedo from the training tubes at the damaged merchant ship. Range on firing was 1100 yards. The torpedo was not seen to run and did not explode.

1159FG/25 - Fired one torpedo from the stern tubes at the damaged merchant ship from 1100 yards. One minute after firing an explosion occurred about 20 yards before the stem of the ship.

1201FG/25 - Fired the second and last torpedo from the stern torpedo tubes at the damaged merchant ship from 1100 yards. This one exploded about 20 yards abaft the stem of the ship 68 seconds after firing. Both these last torpedoes exploded very near to the target and possibly hit the bottom.

1204FG/25 - The ship was seen to steam slowly away towards Penang escorted by the A/S trawler. O 23 meanwhile cleared the area

Between 1200 and 1223 hours, depth charges exploded but none did any damage. Through none were seen it was thought that aircraft were now also hunting O 23. (2)

27 Oct 1942 (position 0.00, 0.00)
At 0330FG/27, near Penang in approximate position 05°40'N, 99°34'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a ship bearing 030°. O 23 then turned towards to close.

At 0343FG/27, it was seen that the ship was an A/S trawler proceeding to the south-east. O 23 then altered course away.

At 0515FG/27, a ship was seen bearing 160°. This was again thought to be an A/S trawler and may have been the same that had been seen earlier. The enemy ship was on a westerly course.

At 0519FG/27, O 23 dived for a day of submerged patrol. No more ships were seen, except for a sailing vessel at 1625FG/27, although it was thought HE was heard twice.

At 1848FG/27, O 23 surfaced. (2)

28 Oct 1942 (position 0.00, 0.00)
At 2225FG/28, south-west of Langkawi in approximate position 05°48'N, 99°15'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted smoke bearing 155°. It was seen to be a ship burning her navigation lights. O 23 turned towards to close to attack.

An hour later the attack was abandoned when it was seen that the ship was a hospital ship proceeding on a course about west. The ship was later seen to alter course to the north-west. (2)

29 Oct 1942 (position 0.00, 0.00)
At 0220FG/29, west-north-west of Penang, in approximate position 05°33'N, 99°28'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a ship bearing 122°. O 23 turned towards to close to investigate.

By 0228FG/29, there were two ship in sight, close to each other. Both were seen to be A/S trawlers. O 23 turned to the north to evade detection. The trawlers were lost from sight at 0245FG/29 and O 23 altered course to the eastwards to arrive of the northern entrance to Penang at dawn.

At 0305FG/29, one of the A/S trawlers was again seen proceeding towards. O 23 again altered course to the north to evade. By 0323FG/29 the trawler was no longer in sight. As it was thought O 23's position was compromised course was set to patrol to the north-west of Pulau Perak. (2)

1 Nov 1942 (position 0.00, 0.00)
At 1829FG/1, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) surfaced after a day of submerged patrol off Pulau Rondo. She then left patrol to return to Colombo. (2)

7 Nov 1942
Around 0920FG/7, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 16th war patrol (3rd in the Far East) at Colombo. She arrived with a defective starboard main engine which had been out of action since 0940FG/3. (2)

14 Nov 1942 (position 0.00, 0.00)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) left patrol to return to Colombo. (2)

20 Nov 1942 (position 0.00, 0.00)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted D/G trials at Colombo. (3)

24 Nov 1942 (position 0.00, 0.00)
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted A/S exercises off Colombo with HMS Scout (Lt.Cdr.(Retd.) H. Lambton, RN). Also practice attacks were made on HMS Scout. (10)

26 Nov 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted practice attacks off Colombo during which HMS Scout (Lt.Cdr.(Retd.) H. Lambton, RN) acted as target. (10)

28 Nov 1942
Around 1800FG/28, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for her 17th war patrol (4th in the Far East). She was ordered to patrol in the Malacca Staits.

For the daily positions of HrMs O 23 during this patrol see the map below.

(2)

20 Dec 1942
Around 1115FG/20, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 17th war patrol (4th in the Far East) at Colombo.

The patrol itself had been uneventful but O 23 suffers from many defects and will have be refitted at Colombo before she is able to go on patrol again. Spare parts had to shipped from the U.K. to make her suitable for offensive operations again. (2)

22 Dec 1942
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was docked in the inner graving dock at Colombo. (10)

2 Jan 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was undocked. (11)

14 Feb 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was again docked in the inner graving dock at Colombo. (11)

18 Feb 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) was undocked. (11)

4 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted engine trials off Colombo. (11)

8 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted exercises off Colombo. (11)

9 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted exercises off Colombo during which a practice attack was made on HMS Devonshire (Capt. D. Young-Jamieson, RN) which had just left the dry dock.

On completion of the exercises HMS Devonshire set course to proceed to the Seychelles. O 23 returned to harbour. (12)

10 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack exercises off Colombo during which HMS Overdale Wyke (?) acted as target. These exercises were followed by gunnery exercises on a target that was being towed by HMS Hoxa (T/Lt. H.P Davies, RNR). And finally A/S exercises were carried out with HMS Okapi (?) and HMIS Rajputana (Lt W.G. Coltham, RIN). (11)

11 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack and A/S exercises off Colombo with HMAS Gawler (Lt.Cdr.(Emgy.) W.J. Seymour, RAN). (11)

13 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack and A/S exercises exercises off Colombo with HMS Scout (Lt. R.G. Woodward, RN). (11)

15 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack exercises off Colombo during which HMS Verbena (Lt. J.R. Freeman, RNR) acted as target. These were followed by A/S exericxses with HMS Overdale Wyke (?). (11)

17 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted exercises off Colombo. Practice attacks were made on the Dutch accomodation / depot ship Plancius by all the officers of O 23. (11)

20 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted exercises off Colombo. Practice attacks were made on HMS Tulip (Lt. C.W. Leadbetter, RNR) which was being escorted by HMS Okapi (?). These were followed by A/S exercises with HMS Tulip and HMS Hoxa (T/Lt. H.P Davies, RNR). (11)

22 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack exercises off Colombo during which HMAS Tamworth (T/Lt. W.H. Deans, RANR(S)) acted as target. HMAS Tamworth was escorted by HMS Overdale Wyke (?), HMS Okapi (?). Following these attack exercises A/S exercises were carried out with HMAS Tamworth and HMS Okapi. (11)

24 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack and A/S exercises off Colombo with HMS Tulip (Lt. C.W. Leadbetter, RNR). (11)

25 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted exercises off Colombo. Practice attacks were made on the Dutch stores ship HrMs Zuiderkruis by all the officers of O 23. (11)

26 Mar 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack exercises off Colombo during which HMAS Tamworth acted as target. HMAS Tamworth (T/Lt. W.H. Deans, RANR(S)) was being escorted by HMS Hoxa (T/Lt. H.P Davies, RNR). These were followed by A/S exercises with the same ships. (11)

30 Mar 1943
During the night of 30-31 March 1943, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted night exercises off Colombo. (11)

1 Apr 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack exercises off Colombo during which HMS Tulip (Lt. C.W. Leadbetter, RNR) acted as target. HMS Tulip was escorted by HMS Overdale Wyke (?). On completion of the attack exercises A/S exercises were carried out with the same ships. (11)

3 Apr 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack exercisses exercises off Colombo during which HMS Scout (Lt. R.G. Woodward, RN) acted as target. These attack exercises were followed by A/S exercises with HMS Scout and HMAS Lismore (T/Lt. L.C.G. Lever, RANR(S)). (11)

7 Apr 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted A/S exercises off Colombo with HMS Hoxa (T/Lt. H.P Davies, RNR) and HMS HDML 1082 (T/Lt. G.G. MacPherson, RNVR).

During the night of 7 to 8 April 1943, HrMs O 23 conducted night exercises off Colombo. (11)

9 Apr 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted independent exercises off Colombo. (11)

12 Apr 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted attack and A/S exercises off Colombo with HMS Verbena (Lt. J.R. Freeman, RNR). (11)

23 Apr 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted A/S exercises off Colombo with HMAS Maryborough (A/Cdr. G.L. Cant, RAN) and HMAS Lismore (T/Lt. L.C.G. Lever, RANR(S)).

On her return to Colombo harbour HrMs O 23 conduced D/G trials. (11)

27 Apr 1943
During the night of 27-28 April 1943, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) conducted night exercises off Colombo. (11)

14 May 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is slightly damaged when the Dutch accomodation / depot ship Plancius slips here moorings during strong winds. O 23 was moored alongside and was damaged by a buoy. A diver found some damage to the submarine which required her to dock again for repairs. (11)

16 May 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is docked at Colombo. (11)

18 May 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is undocked.

During the night of 18-19 May 1943, O 23 conducted night exercises off Colombo.

After around five months of waiting for spare parts to arrive and repairs, O 23 is finally fit for operational patrols again. (11)

22 May 1943
Around 1730FG/22, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for her 18th war patrol (5th in the Far East). She was to patrol in the northern entrance to the Malacca Straits.

For the daily positions of HrMs O 23 during this patrol see the map below.

(2)

31 May 1943 (position 0.00, 0.00)
After dark, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) left patrol to return to Colombo as had been ordered in Capt. S 4's signal timed 0507Z/31. (2)

6 Jun 1943
Around 1115FG/6, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 18th war patrol (5th in the Far East), which had been uneventful, at Colombo. She was escorted in by HMS Balta (T/Lt. W.E. Turner, RNVR) which had joined around 0930FG/6. (2)

15 Jun 1943
Around 1100FG/15, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for her 19th war patrol (6th in the Far East). She was to patrol in the Malacca Straits and to carry out a special operation.

For the daily and attack positions of HrMs O 23 during this patrol see the map below.

(2)

17 Jun 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) makes a short call (1200FG/17 to 2130FG/17) at Trincomalee to take on board material and two British army officers and three Chinese for the special operation. (2)

22 Jun 1943 (position 0.00, 0.00)
At 1400FG/22, north-west of Diamond Head, Sumatra, in position 05°50'N, 96°54'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighed a trawler bearing 187° at a range of about 6 nautical miles. (2)

23 Jun 1943 (position 0.00, 0.00)
At 1530FG/23, north-west of Belawan, Sumatra, in position 04°15'N, 98°30'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) picked up HE bearing 218°.

At 1540FG/23, two mast tops were seen, close inshore, moving an an east-south-east direction. Range was about 7 nautical miles, enemy speed around 10 to 11 knots. By 1600FG/23, the ship was lost from sight. Only once during this period a small puff of smoke was sighted . This appeared behind the mainmast thus giving the impression the vessel might be a small tanker. (2)

25 Jun 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) carried out Special Operation GUSTAVUS II. A rendesvouz, south of the Sembilan Islands, was made with a junk containing the Gustavus party.

At dawn around 0530FG/25, O 23 dived off the Sembilan Islands in approximate position 03°58'N, 100°26'E. Course was set to the rendezvous position.

Between 0930FG/25 and 1000FG/25 a number of junks were seen, coming from the east and passing north of the Sembilan Islands.

At 1000FG/25, a junk was seen coming from the south-east and on reaching the rendezvous position this junk lowered her sail and anchored.

At 1200FG/25, a red blanket was shown on the port quarter and three men were seen to bunch together on the junks bow. The junk was then approached submerged in order to try to identify the men. When about 100 yards away a number of Chinese and one European were seen. The European was identified as Captain Davis which was expected to be on board the junk. O 23 now retired to return the coming night.

At 1500FG/25, south of the Sembilan Islands, in position 03°53.3'N, 100°30.3'E, an A/S trawler was sighted proceeding northwards on course 350°, range was about 3 nautical miles.

At 1841FG/25, O 23 surfaced to the eastern (dark) side of the junk. Captains Broome and Fenner then left the submarine by canoe and proceeded to the junk. They returned shortly afterwards and stated that Captain Davis and one Chinese wished to return to Colombo and that the stores embarked in the submarine were not needed. Fenner then returned to the junk and brought Davis over followed by the Chinese which was to be left in charge during Davis absence. A confrence was then held on board O 23 on completion of which the Chinese was brought back to the junk and the Chinese that was to return to Colombo was embarked and brought on board O 23.

At 2037FG/25, O 23 left the rendezvous and proceeeded so as to continue her patrol. (13)

26 Jun 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) makes a torpedo attack on a small Japanese tanker in ballast near the One Fathom Bank in the Malacca Staits in position 03°02'N, 100°40'E.

1517FG/26 - Surfaced for a surface patrol in the area. Immediately sighted a ship through the periscope. It was not seen from the bridge. The ship was in bearing 118°, distance was about 8 nautical miles, enemy course was about 300°.

1520FG/26 - Dived and commenced an attack as soon as the ship became visible through the periscope. It was first thought to be very large but when it came closer it was seen to be a small empty tanker of about 1000 tons or possibly even less.

1614FG/26 - In position 03°02'N, 100°40'E fired two torpedoes from 700 yards. No hits were obtained and it is quite likely the torpedoes ran under. The target made a sharp alteration towards and fearing a counter attack with depth charges O 23 had to take evasive action. After a few minutes the target altered course and zig-zagged away. It was decided not to surface for gun action as the tanker was armed and the element of surprise was now gone. (2)

27 Jun 1943 (position 0.00, 0.00)
At 0335FG/27, south-west of Penang, in position 04°49'N, 100°02'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN), sighted a trawler proceeding southwards.

At 0600FG/27, HE was picked up coming from the direction of the Penang south entrance channel. It was proceeding in a southern direction. Smoke was then sighted which disappeared close inshore. Obviously a small ship was proceeding southwards.

At 0640FG/27, a very small ship with one black funnel on bridgehouse and a mast forward was sighted bearing 184°, range 2 to 3 nautical miles. Enemy course was approximately 040°. It looked a bit like a tug but was most likely some sort of patrol vessel. The vessel was lost from sight at 0708FG/27, when it disappeared into a rain squall bearing 127°.

(2)

1 Jul 1943 (position 0.00, 0.00)
Around 1910FG/1, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) surfaced after a day of submerged patrol off the north coast of Sumatra. She then left patrol to return to Colombo. (11)

6 Jul 1943
Around 0915FG/6, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 19th war patrol (6th in the Far East) at Colombo.

She was escorted in by the auxiliary patrol trawler HMS Okapi (?) which had joined around 0740FG/6. (2)

24 Jul 1943
Around 2200FG/24, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for her 20th war patrol (7th in the Far East). She was to patrol off Port Blair and in the Malacca Straits. She was also ordered to carry out a special operation.

For the daily positions of HrMs O 23 during this patrol see the map below.

(2)

28 Jul 1943 (position 10.50, 93.02)
At 0426FG/28, about 30 nautical miles west off Little Andaman Island, in position 10°50'N, 93°02'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) encounters the Japanese light cruiser Kashii (offsite link). O 23 was unable to identify the ship sighted and was also unable to attack as she was most likely spotted and the Japanese swiched on a searchlight and took evasive action.

The Japanese cruiser was on a troop transport run from Singapore to Port Blair. (2)

29 Jul 1943
At 0655FG/29, while patrolling off Port Blair, in position 11°35'N, 92°55'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted an A/S trawler bearing 308° at a range of about 4 nautical miles. Enemy course was about 190°. The ships HE had been picked up 5 minutes before.

At 0705FG/29, the masts and funnels of two ships, one thought to be a cargo ship and the other a tanker, were seen bearing 309° at a range of 7 to 8 nautical miles. Their estimated course was about 190°. It looked like these ships were southbound proceeding along the 100 fathom line and were covered to seaward by the A/S trawler. O 23 closed to try to attack but the range could not be closed sufficiently and eventually the attack had to be broken off.

At 0905FG/29, the last ship in sight, the trawler, disappeared in a rain squall.

At 1128FG/29, another A/S trawler was sighted bearing 284°, range 5 nautical miles, course 165°.

At 1232FG/29, the A/S trawler seen at 0655FG/29, was seen again bearing 350°, range 4 nautical miles.

At 1250FG/29, this trawler was seen to open fire with her forward gun. Three minutes later an explosion was heard and a white smoke column was seen near the trawler. More explosions followed in the next half an hour and also aircraft were seen. It looked like an air attack was taking place. O 23 went to 80 feet.

At 1350FG/29, O 23 returned to periscope depth. The A/S trawler (the one first seen at 0655FG/29) was seen 200° at a range of 6 nautical miles. Enemy course was 330°. No other ships were in sight. (14)

30 Jul 1943
At 0635FG/30, while still patrolling off Port Blair, in position 11°41'N, 92°55'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted an A/S trawler leaving the harbour and turning to the southward. Another A/S trawler was seen bearing 237°, range 6 nautical miles. Both eventually disappeared from sight to the southwards.

At 1645FG/30, a landing barge was seen to leave the harbour and proceeding to the southwards.

At 1700FG/30, two ships were seen bearing 200°, range 7 nautical miles. Both of around 2000 tons. One was a cargo ship with two masts and a black funnel on top of a bridgehouse amidships. She had guns mounted fore and aft. The other was also a cargo ship but resembled a tanker. She had two guns, one forwards, one aft. She had a high deck house and high bridge with derrick poles. The landing barge was seen to take station astern of these two ships and the convoy proceeded to position 11°53'N, 92°48.6'E where it altered course to the westwards and entered the bay. It is thought this were the same ships that had been seen on the 28th proceeding southwards.

The ships were not attacked due to the attack limitations imposed upon O 23 in Capt. S 4's signal timed 1623Z/29. (14)

31 Jul 1943 (position 0.00, 0.00)
At 0615FG/31, while still patrolling off Port Blair, in position 11°42'N, 92°54'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighed the same cargo ships that had been seen the previous days. They were leaving the bay they had entered the previous afternoon and proceeded southwards.

At 1630FG/31, the landing barge seen the previous day was now also seen to leave the bay and proceeding southwards.

At 1645FG/31, the cargo ships were seen bearing 199° proceeding on course 010°. They later entered the bay as they had done the previous day. Again they were not attacked due to the imposed attack limitations.

At 2011FG/31, O 23 surfaced and left the Port Blair area as ordered by Capt. S 4 in his signal timed 1118Z/31. (14)

4 Aug 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) carried out Special Operation GUSTAVUS III. A rendesvouz, south of the Sembilan Islands, was made with the same junk as on 25 June 1943 to transfer some of the persons taken on board in Colombo. Also stores were transferred to the junk.

0517FG/4, Dived and commenced to close the rendezvous.

Around noon a junk was sighted at anchor in approximately the rendezvous position. A red blanket was seen on her port quarter. Three men were seen on the bow where they remained for about 10 minutes before they dispersed. One of the Chinese on board the junk was identified by Major Davis as one of the men expected to be on board the junk. O 23 then retired from the area to return after dark.

1400FG/4, Sighted two masts with a funnel behind the mainmast bearing 200°. By 1600FG/4, this ship was to the west of the Sembilan Islands.

By 1600FG/4, this ship was in approximate position 04°02'N, 100°24'E. Enemy course was 350°, speed 9 knots.

1846FG/4, Surfaced to the eastern (dark) side of the junk. Major Davis and Captain Fenner then left the submarine by canoe and proceeded to the junk. Not long afterwards Captain Fenner returned with the message that the junk was ready to receive the stores. All stores were then brought onto the deck and then transferred to the junk with boats in a glassy calm sea.

2110FG/4, the transfer of Major Davis, three Chinese and sstores was completed.

2140FG/4, Captain Fenner returned to O 23 with the latest reconnaissance reports which then retired from the area to continue her patrol. (13)

5 Aug 1943
At 1920FG/5, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a ship very nearby about 30 nautical miles south-south-west of Penang near position 04°55'N, 100°05'E. The torpedo tubes could not be brought to the ready quickly enough for an attack. O 23 surfaced and gave chase but she was spotted by the enemy and attacked with gunfire. O 23 had to submerge and was then depth charged by an A/S vessel but she suffered no damage and was able to slip away. O 23 surfaced at 2157FG/5 with no ships in sight. (2)

6 Aug 1943 (position 0.00, 0.00)
At 1734FG/6, south-west of Penang, in approximate position 05°05'N, 100°01'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a small warship bearing 087° at a range of 2.5 nautical miles. Enemy course was 225°. It was thought to be a W-13 class minesweeper.

[More likely it was a submarine chaser, Ch-7 had departed Penang that afternoon for an A/S patrol.] (14)

7 Aug 1943 (position 0.00, 0.00)
At 0230FG/7, south-west of Penang, in approximate position 05°03'N, 99°53'E, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) sighted a small ship bearing 270°. Course of the ship as about 070°. It was thought to be a small tanker and an attack was started. Whn the range had decreased to 1200 yards it was seen that the target was too small to be a torpedo target. It was then also seen that the target was an A/S trawler proceeding at very slow speed. O 23 then evaded and the target was later lost in a rain squall. (14)

10 Aug 1943 (position 0.00, 0.00)
At 1957FG/7, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) surfaced in position 06°09'N, 94°54'E, after a day of submerged patrol near Pulau Rondo. She then set course to return to Colombo. (14)

16 Aug 1943
Around 1000FG/16, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) ended her 20th war patrol (7th in the Far East) at Colombo.

She was escorted in by HMS Balta (T/Lt. W.E. Turner, RNVR) which had joined around 0800FG/16. (2)

24 Aug 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is docked in the inner graving dock at Colombo. (11)

31 Aug 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is undocked. (11)

8 Sep 1943
As some repairs had been made to the pressure hull, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN), made a deep dive off Colombo today. No problems were found. Also an exercise was carried out during which HMS Frobisher (Capt. J.F.W. Mudford, RN), which was departing Colombo, acted as target. (11)

11 Sep 1943
Around 1100FG/11, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Colombo for Aden. This is the first leg of the trip to the U.K. where she was to refit.

For the daily positions of HrMs O 23 during this passage see the map below.

(2)

21 Sep 1943
Around 0830C/21, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Aden from Colombo. (2)

22 Sep 1943
Around 0800C/22, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Aden for Port Said. (2)

27 Sep 1943
Around 0835C/27, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) entered the Suez Canal and commenced the northbound passage. She arrived at Port Said around 1730C/27. (2)

3 Oct 1943
Around 1630C/3, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Port Said for Malta. (2)

4 Oct 1943

Convoy MKS 27.

This convoy departed Alexandria on 4 October 1943.

It was made up of the following merchant vessels;
Bassethound (British (tanker), 1174 GRT, built 1934), Cerion (British, 2588 GRT, built 1938), Clan Forbes (British, 7529 GRT, built 1938), Clan MacGillivray (British, 5023 GRT, built 1911), Defender (British, 8078 GRT, built 1915), Euryades (British, 5801 GRT, built 1913), Fort Connolly (British, 7133 GRT, built 1943), Fort Fork (British, 7134 GRT, built 1942), Fort Remy (British, 7127 GRT, built 1943), Middlesex Trader (British, 7421 GRT, built 1942), Norman Monarch (British, 7005 GRT, built 1943), Ocean Valentine (British, 7174 GRT, built 1942), Ocean Viking (British, 7174 GRT, built 1941), Orna (British, 6779 GRT, built 1938), Pundit (British, 5305 GRT, built 1919), San Rafael (Panamanian, 5379 GRT, built 1919) and Saparoea (Dutch, 6668 GRT, built 1920).

On departure from Alexandria the convoy was escorted by the minesweepers HMS Hythe (Lt.Cdr. L.B. Miller, RN), HMS Rye (A/Lt.Cdr. J.A. Pearson, DSC and Bar, RNR) and the A/S whaler HMSAS Protea (Lt. A. Thomas, DSC, SANF).

On 5 October 1943, the A/S whaler HMSAS Southern Isles (Lt. M.R.T. Terry-Lloyd, SANF) departed Benghazi. she joined the convoy [date unknown].

On 9 October 1943, the Bassethound arrived at Benghazi after having been detached from the convoy.

On 9 October 1943, the following merchant vessels arrived at Malta after having been detached from the convoy;
Cerion, Defender, Euryades, Fort Connolly, Fort Fork, Fort Remy, Middlesex Trader, Norman Monarch, Ocean Valentine, Ocean Viking and Orna.

Also on the 9th the following merchant vessels joined the convoy coming from Malta;
George Washington Carver (American, 7176 GRT, built 1943), John Grier Hibben (American, 7176 GRT, built 1943) and Rohna (British, 8602 GRT, built 1926). Also joining from Malta were the submarine HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) and the landing ship HMS Queen Emma (Capt.(Retd.) G.L.D. Gibbs, DSO and Bar, RN).

On 9 October 1943, the George Washington Carver and John Grier Hibben were detached to Bizerta.

On 10 October 1943, the following merchant vessels joined the convoy coming from Bone;
Charles A. McAllister (American, 7176 GRT, built 1943), Empire Garrick (British (tanker), 8128 GRT, built 1942), Queen Adelaide (British, 4933 GRT, built 1936), Toronto (Norwegian, 5018 GRT, built 1928) and Yenangyaung (British, 5447 GRT, built 1937).

On 10 October 1943, the following merchant vessel Mont Viso (French, 4531 GRT, built 1921) joined the convoy coming from Philippeville while the Yenangyaung was detached to the place.

At 0109A/11, HMS Hythe was hit by a homing torpedo from the German submarine U-371 in position 37°04'N, 05°00'E. Twenty survivors were picked up by HMSAS Southern Isles which was being screened by HMS Rye while doing so.

Following the sinking of HMS Hythe the escort destroyer HMS Tynedale (Lt.Cdr. J.J.S. Yorke, DSC, RN) left Algiers and joined the convoy later that day.

On 11 October 1943, the following merchant vessels joined the convoy coming from Algiers;
Filleigh (British, 4856 GRT, built 1928), Fort Fraser (British, 7126 GRT, built 1942) and P.L.M. 17 (French, 4008 GRT, built 1922). Also joining from Algiers was the landing ship HMS Misoa (Lt.Cdr. J.W. Grace, DSC, RD, RNR). The Charles A. McAllister and Empire Garrick were detached to Algiers.

On 13 October 1943, the following merchant vessels joined the convoy coming from Oran;
Empire Flame (British, 7069 GRT, built 1941) and Spondilus (British (tanker), 7402 GRT, built 1927). The Mont Viso, P.L.M. 17 and Rohna were detached to Oran.

The convoy arrived at Gibraltar on 14 October 1943.

7 Oct 1943
Around 1220A/7, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Malta. She was escorted in by HMS Bute (T/Lt. C.W. Hancock, RNR) which had joined around 0810A/7. (2)

8 Oct 1943
Around 0530A/8, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Malta for Gibraltar. She joined convoy MKS 27 for the passage.

[For more info on this convoy see the event Convoy MKS 27 for 4 October 1943.] (2)

14 Oct 1943
HMS Tynedale (Lt.Cdr. J.J.S. Yorke, DSC, RN), HMS Rye (A/Lt.Cdr. J.A. Pearson, DSC and Bar, RNR), HMSAS Protea (Lt. A. Thomas, DSC, SANF), HMSAS Southern Isles (Lt. M.R.T. Terry-Lloyd, SANF), HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN), HMS Queen Emma (Capt.(Retd.) G.L.D. Gibbs, DSO and Bar, RN) and HMS Misoa (Lt.Cdr. J.W. Grace, DSC, RD, RNR) arrived at Gibraltar with convoy MKS 27. (15)

20 Oct 1943
Around 1220A/20, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Gibraltar for Holy Loch. (2)

29 Oct 1943
Around 0745A/29, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN), makes rendezvous off Bishops Rock with her escort, HMS La Capricieuse (Lt.Cdr.(Retd.) C.M. Norman, RN). They then set course for Holy Loch. (2)

30 Oct 1943
Around 1330A/30, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Holy Loch from Gibraltar. (2)

1 Nov 1943
Around 1800A/11, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) departed Holy Loch for Dundee. She makes the passage together with the British submarine HMS Spiteful (Lt.Cdr. F.H. Sherwood, DSC, RCNVR). The submarines are escorted by the British minesweeper HMS La Capricieuse (Lt.Cdr.(Retd.) C.M. Norman, RN).

Around 0820A/3, off Scapa Flow, the other two ships left O 23. The ASW trawler HMS Thornwick Bay (A/Skr.Lt. J. Windram, RNR) took over the escort of this submarine towards Dundee. (2)

4 Nov 1943
Around 1100A/4, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) arrived at Dundee from Holy Loch. (2)

16 Nov 1943
HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) proceeded from Dundee to Grangemouth where she was to undergo an extensive refit. (16)

27 Jan 1944
During her refit by the Grangemouth Dockyard, HrMs O 23 (Lt.Cdr. A.M. Valkenburg, RNN) is docked. (16)

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