U-boat Archive - BDU KTB PG30250

F.d.U./B.d.U.'S War Log

16 - 31 October 1939

PG30250

Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.


		16.10			The general impression in the Atlantic is as follows:
		Group Headquarters West			Position "GELB" was a very happy choice. Now that a few more reports of sinkings have been received, the total tonnage sunk in the last 3 days has risen to nearly 56,000. The enemy then immediately changed merchant shipping route and sent anti-S/M forces to this area. There is therefore no purpose in remaining long in this position. The boats will be ordered to proceed on to area "SCHWARZ". During the last few days the British news service has several times stated that several German U-boats had been sunk, including 2 of the largest and newest type. In spite of the many sinkings in area "GLEB", only U 37 and U 48 had reported. U 42, 45 and 46 were therefore ordered to give their position and situation report. There were no misgivings about this order, as the boats are leaving their areas and their presence has in any case become known through their activities. U 46 reported, but U 42 and U 45 did not. It can therefore only be taken for certain that U 37, U 46 and U 48 are proceeding on.

		17.10

		0055			Radio signal from U 46 reporting the sighting of a large cruiser, course north, 14 knots. It could not be gathered whether the boat was shadowing or trying to regain contact.

					U 34 sailed for her operations area.

		0851			U 46 reported a convoy of 20 ships escorted by 12 destroyers, on a main course northeast. Boat was shadowing, lost contact for a while, regained it and shadowed until afternoon. Then English costal radio stations received reports of the torpedoing of 2 ships. At 2000 U 37 reported: convoy scattered, one ship sunk. She must therefore have reached the convoy. After the convoy had scattered, contact was lost. In order to regain it, U 37 ordered a reconnaissance line to be formed the following morning which is intended to pick up the convoy from the northeast.

		18.10			At 0029 U 48 sighted the enemy again. She reported: "A straggler sunk. A second straggler steering a northerly course in square 6789 BE. All torpedoes used."
					The boat shadowed this ship. At 0500 U 37 gave the order to act on U 48's report, thus canceling the order for a reconnaissance line. At first light U 48 again sighted the convoy, which had apparently reassembled meanwhile. At 0630 a second U-boat was reported in sight of a ship. Therefore at least one more boat had reached the enemy on U 48's shadower's report. Towards midday a/c appeared, contact was lost. U 37 ordered the boats which had been driven off to go to position "SCHWARZ". (For radio review of the attack see appendix). Reports received show that 5 ships were sunk for certain, probably 4. But again torpedo failures were reported. 2 explosions at the end of the run, 2 surface runners and 2 explosions at the end of the safety range. It is first

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

in attacks on such strongly escorted convoys that these can have the most unpleasant and serious consequences for the boat, because they give it away, quite apart from the approach made for nothing and which can often not be repeated for many hours.

U 48 has been ordered to start back as she has no more torpedoes. An enquiry elicited the fact that U 37 and U 46 will only have 30 and 5 tons of fuel respectively when they reach position "SCHWARZ". U 46 has therefore been allocated an operations area closer to. (off Lisbon).

U 25 sailed for her operations area.

19.10

Still no report from U 40 on her Channel passage. This fact, added to radio intelligence reports on the 14th that 4 U-boats had been sunk, one of them by French forces, gives rise to the suspicion that U-40 and U 12 (see F.O. U/B West's War Log) have been lost in the Channel.

According to radio intelligence reports 2 boats were sighted in the Channel west of the Straits of Dover, so it must be assumed that the boats got through the mined Dover-Calais narrows and were lost west of this. I view the question of the Channel passage as follows:

1)	U 31 passed the Dover-Calais narrows once, U 15 twice, probably also U 12 and U 40 once each.
2)	U 35 did not have to turn back, her doing so does not disprove the possibility of getting through the Channel.
3)	Danger from mines must be regarded as the most dangerous aspect of the Channel passage. In all probability however, there have not been any victims of mines as yet, possibly U 12 on her way back.
4)	Losses of boats so far have been 2 in the Atlantic or North Sea (U 27, 30), 2 probably in the Atlantic (U 42, 45), 2 perhaps in the Channel. These losses do not preclude the Channel passage.
5)	The danger of surprise air attack is no greater in the Channel than in the open sea area, as boats have to proceed submerged by day anyhow.
6)	I am therefore loath at present to give up the enormous advantage of the short approach route through the Channel. But the question will have to come up for constant consideration.

U 46 encountered a fresh convoy of 15 ships, but she was soon driven off by destroyers and lost contact. On the orders of Naval War Staff, the area in which unrestricted action can be taken against darkened ships has been extended to 30⁰ west.

20.10

There is so much damage to U 32's engines that they will have to be exchanged. The boat was to have sailed within the next few days. Now she will be out of action for several weeks. She was just about to load mines. This will have far reaching consequences.

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

					U 31 will have to take over her operation and will thus not be able to sail until 3 days later. The operation originally assigned to this boat will have to be postponed. This is an excellent example of what happens almost all the time. Again and again plans are reversed because completion dates for the boats are postponed. One thing is certain: the M.A.N. engines have not proved their worth because their casing is too light. Presumably things will not improve until all the boats have been fitted with the new casings.

		21.10			U 31 and U 53 sailed for their operations areas.
					U 31 to mine Loch Ewe with TMB in accordance with operations Order No. 9 (the operation originally intended for U 32).
					U 53 is to proceed first to an area southwest of Ireland. She is to operate there against merchant shipping until U 26, which is sailing on 22.10, has had time to carry out her minelaying operation.

		22.10			U 26 sailed for Gibraltar. After minelaying (Operations Order No. 6) it is intended to send her to the western Mediterranean together with U 25 and U 53. As she is first to carry out a mining operation she may only be issued with absolutely essential confidential books and cypher material. (Standing War Order No. 17). The consequent disadvantages and difficulties when working together with other boats have to be accepted, as the risk of the confidential books and cypher material falling into enemy hands if the boat is lost in shallow water is too great. This point has to be taken into account in all operations in shallow water.

		23.10			U 34, which sailed on 17.10, has orders to take up a position within disposition "SCHWARZ". As events have made this disposition redundant, there is no point now in sending her there, not only because she would be there alone, but also because her fuel stocks would only permit her to operate there for a short time.
					As far as supplies of fuel are concerned, information received meanwhile from Naval War Staff shows that considerable difficulty has been encountered and supply is by no means assured. THe first experiment in supplying is therefore to be made with a boat which is in any case stationed near the supply points agreed and does not depend on supply for her operation. This could be done with U 25, U 26 or U 53 on their way out or back (operations area Mediterranean). Fuel has to be ordered 10 days ahead and has been requested for 1 November.
					On the subject of U-boat losses: of the Atlantic and North Sea boats, U 27, U 39 and U 12 are definitely lost, U 42 and U 45 probably, U 40 possibly. The following is known about the boats: U 27 reported on 19.9 that she was leaving her operations area. There is no information on U 39 since she sailed. One major part of both crews are prisoners of war. This means that the boats were probably surprised on the surface and attacked with gunfire and possibly also by a/c. It is possible that they were so damaged as to be unable to dive, so that the crews had to abandon the boats in the face of the enemy and sink them. The large number of survivors cannot be explained in any other way. If they had been destroyed underwater the losses would have been much greater. U 12 passed the line Dover-Calais and was operating west of this; this is proved

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

by a number of sightings and attack reports, which on the whole have proved very accurate apart from the first weeks of war, during which they were not very reliable. A radio intelligence report suggests that the boat may have been rammed. (For the rest, see F.O. U/B West's War Log).

Nothing has been heard of U 42 and U 45 since they sailed. They did not reply to orders to report their positions. Enemy broadcasts and the enemy press indicate that there was an anti-S/M hunt on 13th October during which 2 large boats were sunk. One report mentions S.S. "Stonepool" as having contributed to the destruction of U-boats. On the 13th she had reported that she was in action with a U-boat.On the 15th she reported another U-boat; 2 destroyer flotillas (or at least part of them), were sent out from Portland to this position. According to another report, part of the crew of a U-boat, including the C.O., were on board a destroyer, which had picked up survivors from S.S. "Bretagne". Yet another report says that a member of the crew of a steamer, who had fired on a U-boat with his gun, observed that later on destroyers came up and sank the U-boat, which was no longer able to dive. (This cannot be S.S. Stonepool).

Actions are therefore said to have been fought between steamers and U-boats. Both steamers got away and in both cases the U-boat is said to have been destroyed at least one of them on the surface.

There are still no reports from U 40 on her Channel passage, but a steamer has been torpedoed in the sea area west of the Channel and a U-boat sighted twice. (Radio intelligence reports). There cannot be any other boat there except U 40. It is therefore possible that she got through the Channel after all, but that her transmitter is out of action and she has not been able to report. It is therefore by no means certain that she is lost.

Summary:
a)	Maximum number of losses: 6 boats, of which 3 were fairly certainly destroyed above water (U 27, 39 and U 43 or 45), 2 probably underwater (U 12 and U 40. Mine hits possible). 1 cause of loss doubtful.
b)	Minimum number of losses: 3, of which 2 above water (U 27, 39), 1 underwater (U 12).
c)	Probable losses: 5 boats, of which 3 above water (U 27, 39 and U 42 or U 45), 1 underwater (U 12) and one doubtful (U 42 or U 45).
As experience in the world war showed, losses on the surface are usually due to:
1)	The risks which the boat runs when waging war in accordance with prize law.
2)	The risks which the boat runs in a gun action with an armed merchant vessel. One hit may render the boat incapable of diving and therefore the certain prey of destroyers. (It is not surprising that circumstances are different from those in the world war. At that time steamers were only gradually being armed; today all this has apparently been carefully planned and the effect of

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

	this form of defense must therefore be expected to be greater).
3)	A surprise encounter with the enemy, especially in poor visibility. (This danger has risen considerably since the world war, because of a/c).
4)	Occasional carelessness on the part of the boat, especially after successful operations or when making long passages through areas of little shipping.
The dangers listed under 3) and 4) can only be dealt with by the crews themselves, but the prize war does involve additional dangers and losses, which can only be eliminated if,
1)	The prize war is renounced, i.e. only such ships are attacked as may be attacked without warning, or
2)	we resort to unrestricted warfare. In both cases the U-boats would have to be forbidden to use their guns,
	a) to stop ships or to quell resistance.
	b) to sink ships.

Of its nature the U-boat is intended to fight with torpedoes and not with guns. Her strength is in being able to make a surprise attack and her protection in deep diving. A full-scale torpedo attack always promises success; a gun action, which is always full-scale as soon as the boat is within range of the enemy guns does not by any means promise the same results. Nevertheless it must not be forgotten that she needs her guns to stop the ship and break resistance when she is not from the first in a position to fire a torpedo at the enemy. It takes a long time to haul ahead and it is not always possible. To renounce the use of guns altogether would therefore lower the chances of success considerably.

Present losses are apparently very high. They exceed supplies of new boats and must therefore lead to paralysis of U-boat warfare if no means can be devised of keeping them lower. But measures to prevent losses must never be on such a scale that they prejudice the success of warfare. U-boat warfare will always mean considerable losses and those have to be taken into account. It is necessary to preserve the correct proportions between the number of boats operating and the success to be expected.

In this connection the Channel problem had to be re-examined in the light of information on the present war situation and also of world war experiences. It is necessary to distinguish between the Channel,

1) as an operations area

2) as a route.

The Channel as Operations Area:

A large proportion of enemy merchant shipping sails in the Channel. The main part of this traffic is destined for the Thames ports and the east coast, therefore proceeds through the whole length of the Channel. U-boats find many worthwhile targets here and are well able to attack these ships. Cross-channel traffic is undoubtedly as heavy and particularly important because it is mainly

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

troop and war material transport. It is presumably heavier in the east than in the west owing to the shorter routes. This traffic proceeds at night, strongly escorted, and consists of fast ships. The chances of attacking it are therefore considerably less favorable than in the case of the through-channel traffic. Patrol in the Channel is strong everywhere. Anti-S/M defenses are strongest in the Dover-Calais Straits and northeast of this line; boats are better able to attack in the somewhat wider west sector, where they are better protected by greater depths of water. Provided they can attack without warning, this is a good operations area for U-boats. War against merchant shipping according to prize law is out of the question here however, owing to the patrols and the proximity of the enemy bases.

The Channel as a Route:

If the Channel is passable at all, the advantages of this route are many. It means:

a)	Saving time on the outward passage, i.e. a longer period in operations areas.
b)	Saving fuel, i.e., raising the range of the boats, or giving them greater freedom of action.
c)	Better prospects of attacking on the outward and return passages.
d)	Better use of personnel and material by shortening passages through areas in which the boat is in danger, but has little chance to attack herself.
The disadvantages are as follows:
a)	Greater danger to the boats in the narrower sea area, in shallow water, from anti-S/M operations, anti-S/M nets and barrages.
b)	Greater navigational difficulties.
c)	Greater strain on the crew on passage.
I have come to the following conclusions:
1)	The question of passage through the Channel must be kept under constant revision. Decisions will vary from case to case according to circumstances. In principle the Channel can be regarded as passable.
2)	The enemy must know as little as possible of U-boats passing through the Dover-Calais Straits. Everything which would cause him to lay barrages or increase his patrol must be avoided. Within a fixed zone therefore no direct attacks are to be made. Mining operations are not affected.
3)	The Channel must on no account be abandoned as an operations area, but only attacks without warning can be made.
4)	As long as the through passage is possible, the Channel as operations area must be reserved for small boats. Such operations must not exceed 8-10 days, as due to the strong patrols, a sharper look-out and greater concentration are required than in open sea areas and any slackening is more

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

5)	Boats should concentrate on the routes along the coasts. Attacks on cross-channel traffic are less likely to be successful and are therefore of secondary importance.
6)	Apart from torpedo operations, mining operations must be planned to cover such areas in which the operation of boats with torpedoes are not promising, i.e. areas of shallow water or strong anti-S/M activity.
7)	Everything must be done to get information on the Channel passage. Air reconnaissance must take in the Dover-Calais line at regular intervals. It may also be necessary sometimes to send a U-boat there for reconnaissance purposes.

24.10

U 37 reports: 2 ships sunk today off Gibraltar, one Q ship hit. Depth charged for 9 hours. Fuel running out. Starting return passage.

Presumably the boat went up close to Gibraltar. Her observations of this area are important for U 26 and U 25 and 53. She has been ordered to report her experiences as soon as circumstances permit.

25.10

U 48 entered Kiel. She sank:

French tanker "Emile Miquet"	14,115	tons
English S.S. "Herouspool"	5,202	tons
English S.S. "Sueaton"	6,903	tons
Unidentified ship from a convoy believed it to be "City of Mandalay"	3,667	tons
Therefore certainly more than	7,014	tons
29,897 tons and probably	36,911	tons

A very successful patrol, especially as it only lasted 3 weeks. U 48 used all her torpedoes, but reports 5 failures, which caused her to lose several ships which would otherwise have certainly been sunk. It is unnecessary to go into the causes and results of these failures again. The Torpedo Inspectorate is being kept informed, and the importance stressed: B.d.U. is in close contact with the Inspectorate.

U 46 sighted a convoy from her position 60 miles northwest of Lisbon. U 25, which was assumed to be off the southwest corner of Ireland, was ordered to take action. Provided contact is maintained, it might be possible for her to reach the convoy, as for the time being the enemy's course is restricted by the coast line. This is an experiment to discover if it is any good to have a few boats working together over a large area. Contact was lost after 4 hours.

26.10

As U 46 did not regain contact, but reported that she was leaving her operations area because of lack of fuel, it was no longer possible for U 25 to operate against the convoy. Meanwhile this boat had come a long way south. She was allocated a new operations area northwest of Cape Finisterre.

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

The following boats are expected to be ready for operations next:

U 33	on	29.10	U 38	on	8.11
43	"	1.11	28	"	8.11
41	"	2.11	29	"	11.11
49	"	4.11	47	"	13.11
			35	"	13.11

I consider the following mining operations to be of next importance:

1)	inside the Bristol Channel, north of the Foreland
2)	off Swansea
3)	off Milford Haven.

Information available suggests that they would be very successful. But as they mean entering an area which is probably strongly patrolled, they must be carried out as soon as possible, before anti-S/M defenses reach their full extent.

U-boats of the 2nd U-Flotilla must be considered for this, because of their range; i.e. U 33, U 28, and U 29. Boats at operational readiness will therefore have to be divided into a mining and an operational group.

I intend to assemble the latter, up to 4 boats, in the area southwest of Ireland. They are then to take up an attacking disposition south and west of Portugal with the purpose of intercepting traffic north-bound from Gibraltar. Later a disposition is planned northwest of Cape Finisterre at about the time when U 47 should have arrived (Operations Order No. 11).

27.10

In order to lessen our losses and based on the reflections set out in the War Log on 23.10, I have decided to issue the following orders:

1)	Boats may not board ships which have been stopped, for examination.
2)	Ships are to be sunk by torpedo only, even when they are only attacked after examination (which can now only consist in looking through the papers) or after resistance has been quelled with gunfire.

28.10

U 37 reported a convoy near the coast off Finisterre, course northeast. Contact lost after an hour.

The French Admiralty announced the sinking of a German U-boat in the Atlantic. Corpses were said to have been salvaged.

29.10

Naval War Staff has ordered that passenger ships in enemy convoy be attacked.

U 33 sailed for a minelaying operation north of the Foreland.

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Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.

U 25 and U 34 were ordered to make a situation report. I must know whether the French Admiralty's claim concerns one of these boats. It might of course be U 40, but she could not answer, as presumably her transmitter is out of order (see 22.10). After going into the question of keeping losses down again, I have decided only to order the boats to keep a sufficient distance in gun actions, and not to go all out. I do not think it necessary or justifiable to restrict the use of guns further, e.g.

a)	to order the boats to avoid all gun actions, i.e. to leave the enemy as soon as opposition is encountered, or
b)	to renounce the use of guns altogether.

Commanding officers must be required not to go all out for the enemy, but to keep at a range which makes it impossible for the enemy to use his guns effectively, or to break off the action if they are faced with superior guns.

U 31 reported: "Operation carried out". (Loch Ewe). U 37's report of experiences off Gibraltar received:

1)	Patrol by Q ships, motor vessels and a/c. Cooperation between these.
2)	Air patrol in the area Cape Spartel, Trafalgar, St. Vincent Larache. Hunts apparently only with hydrophones, no location.
3)	Traffic: ships making 9 knots and over are routed independently, more than 10 miles south of the usual steamer routes.

This report gives valuable information for the operation of U 25, U 26 and U 53, which are to pass through the Straits of Gibraltar into the Mediterranean.

A conference was held between B.d.U. and the General Staff of the G.A.F. on the problem of getting more information on the Channel.The G.A.F. agreed to fly an extensive photographic reconnaissance of the whole Dover-Calais area. It remains to be seen whether pictures taken of the surface of the sea from such a height can provide any practical clues as to mines and net barrages and other details of navigational importance. The only experiences are of much smaller sea areas. I am of the opinion however, that every means of reconnaissance must be used. Even if the results cannot be analyzed accurately from a navigational standpoint, they will still be of great value.

30.10

Situation reports received from U 25 and U 34, thus the French Admiralty's claim can only refer to U 40, whose radio is apparently out of action. It is not at all impossible however, that the reports are connected with the loss of U 16 off Dover (see F.O. U/B West's War Log). U 25 has only observed slight neutral single-ship traffic and torpedo boats or patrolling destroyers.

U 34 sank a steamer from a convoy off the west entrance to the Channel, torpedoed 3 others, but could not observe results owing to anti-S/M activity. She is returning because of a crack in the inner compensating tank.

- 47 -

Date	Position, Wind, Weather
and	Sea State, Illumination,	Events
Time	Air Pressure, Moonlight etc.


		31.10			U 31 entered port. She encountered no patrol off Loch Ewe. There is however, a net barrage in the bay, in which the boat was entangled for some time, as she did not see the flat buoys until too late. There was a hospital ship inside, but nothing else. As it did not seem possible to get inside, the boat laid the mines across the entrance to the bay at the minimum safety distance. The position of the mines is excellent. Success seems certain, but it is doubtful if we shall hear anything about it.

					U 25 reported a convoy northwest of Finisterre. This is the second convoy reported within a few days in this area, fairly close to the coast. This too was steering a main course to the north. It is remarkable that all the 4 convoys reported so far have been north-bound. South-bound traffic apparently keeps further to the west.

					The problem of torpedo failures is unfortunately still far from being solved. U 25 reports 4 failures at one stopped ship, shots at short range. The Torpedo Inspectorate's instructions were observed. There is therefore no longer any doubt that the Torpedo Inspectorate themselves do not understand the matter. At present torpedoes cannot be fired with non-contact firing units, as this has led to premature detonation. Their depth setting has to be 2 meters less than the draught of their target. There depth may not be less than 3 meters, as otherwise there may be surface runners in which especially the engines of the G7a may be damaged. Exact instructions are given for setting the safety range and these are observed. Nevertheless at least 30% of the torpedoes are duds. They either do not detonate at all or they detonate in the wrong place. There does not seem to be any sense in issuing new instructions to the boats as they never lead to the desired results. The Commanding Officers must be losing confidence in their torpedoes. In the end their fighting spirit will suffer. The torpedo failure problem is at present the most urgent of all the problems of U-boat warfare.





					(signed): Dönitz
					Rear Admiral and B.d.U.

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