A detailed KTB from 1944 - BdU: "Don't get cocky"

[sublynx]

A perfect war diary:

http://www.uboatarchive.net/KTB482-1.htm

A very detailed report on an astonishingly succesful patrol from late 1944 and thanks to that I got some confirmation on some things that have been a bit unclear to me so far.

Among them:
1. The U-boat assessed the speed of an escort by counting the revolutions per minute of the propellers
2. A homing torpedo was used with a non-homing setting
3. The U-boat that was depth charged used some kind of evasive action ("hakenschlagen" or "course changes") along BOLD launches

It's still unclear to me if that hakenschlagen is just random course changes or well thought-out evasive maneuvers.

U 482's first patrol was a huge success considering the overwhelming odds. The commander Matuschka got the German Cross in Gold while still at sea. BdU also sent a message about the need to "not get cocky".

Matuschka and his well-trainded but green men were all killed a couple of months after the writing of the report. A Norwegian Sunderland spotted them and the veterans of 17th Escort Group were directed to the boat and HMS Ascension had one or two hedgehogs landing on their obsolescent boat.

Reading Matuschka's detailed, energetic and smart report made me pause for a moment, thinking about what a waste his death was. If only his skillset and dedication could have been used for peaceful purposes.

[Mittelwaechter]

Hakenschlagen is available in SH3 - ask your LI for manouvers.

A small course correction enables the escort above to extrapolate your course from the previously assumed course and run the next depth charge attack close to you.
A Haken (hook) for 90° - or a Doppelhaken (double hook) for 180° shall get you out of the escorts sensors, blinded by the disturbed water due to the depth charges.

In SH3 you are in the deaf baffles after an attack run - and may stay there pretty long, dependent on the direction the escort takes after attacking you.

A homing torpedo had an additional sensor (two passive hydrophones) connected to the steering. Similar to the magnetic fuse connected to the pistol, it was easily to be switched off - by disconnecting a circuit.
Why should they want to carry a torpedo over thousands of miles - perfectly capable sinking a slow freighter with impact/mag fuse, but unable to do so? The homing device was an optional measure, to enhance the self defence capabilities of the U-Boot. Some torpedos were equipped with it.

The speed of an escort to attack was not to be estimated like the speed of a slow moving freighter. The correct speed setting is the most decisive factor in a torpedo attack. Even from a short distance, the few knots estimated wrong would sent the torpedo forward or behind the target.


Mankind could grant every member a full life. Enjoy family and friends, watch the kids grow and develop your full potential to contribute to the community.
But some interested entity teaches us war to be a necessity...

[bstanko6]

I read the KTB and I wonder what depth A was?

[Mittelwaechter]

It's a secret, not to be told to curious people like you...

[bstanko6]

Wow!

[sublynx]

IIRC, A = 80, so in the KTB's 2A is 160 meters depth, A-80 = 40 meters.

[bstanko6]

I appreciate that

[Mittelwaechter]

They fixed a certain depth as A to have a common reference when talking/writing about (120 meters maybe).
As long as bstanko6 doesn't know what depth A has been defined to, he can't know what depth the German U-Boote could reach. 'A' was defined later in war, when the Germans built better U-Boote, able to dive deeper. The allies should not get that information.

If 'A' were 80 meters, A - 80 would be surfaced. 2A would be 160 meters - correct.

[20000 Leagues]

That was an interesting read. Thanks for posting. I was playing with some simmers who were of the opinion that attacking destroyers should be discounted as it wasn't historically accurate. Nice to see that taking shots at and sinking them was in fact, historically accurate!

[Mittelwaechter]

The job was to sink freighters.

But in favourable position they could/should attack destroyers and escorts. They shouldn't get after them, risk anything to attack them, but an escort at 12 kts merrily crossing the bow in calm waters?

Ready tube 3 - Eto - Impact pistol only - 2.5 meters depthsetting - distance 1200 meters - bow left - AOB 70 - revolutions for 12 Kts, Herr Kaleun - LOS!

The homing torpedos were designed to sink escorts - for targets doing 12 Kts or faster. A wolfpack sinking half the escort screen would have had a feast on the convoy.

There were some problems still to solve: the sensors were unreliable, could be easily distracted (by foxers - towed devices making noise), most of the time the weather conditions were not good enough to attack destroyers or escorts. They didn't even attack freighters in bad/unsuitable conditions.
(should be SH3 sea/wind state ~ 10/11 and above)

DDs/DEs/Other sunk by German Uboats:
USS Bristol (DD-453) - U371
USS Buck (DD-420) - U616
USS Jacob Jones (DD-130) - U578
USS Leary (DD-158) - U275
USS Reuben James (DD-245) - U552
USS Fechteler (DE-157) - U967
USS Fiske (DE-143) - U804
USS Frederick C. Davis (DE-136) - U546
USS Leopold (DE-319) - U255
USS PC-558 (Submarine Chaser) - U230
USCGC Alexander Hamilton (WPG-34) (Coast Guard) - U132
USCGC Acacia (WAGL-200) (Coast Guard - former Minelayer) - U161 (sunk by Gunfire!)
USS Eagle Boat 56 (PE-56) (Gunboat) - U853
USS Plymouth (PG-57) - U566 ((Gunboat)
USS YP-389 (Patrol Boat) - U??? (sunk by Gunfire!)

That's just the US Americans.

Here have the British:
https://en.wikipedia.org/wiki/List_o...n_World_War_II

__________________________________________________ _______________

EDIT: (06/30/16) Flower Class Corvettes attacked successfully by German Uboats:

Canadian
HMCS Alberni (K103) - U 480 (escort) (= while assigned to a convoy as escort)
HMCS Charlottetown (1941) - U 517
HMCS Lévis (K115) - U 74 (escort)
HMCS Regina (K234) - U 667 (escort)
HMCS Shawinigan (K136) U 1228
HMCS Spikenard (K198) - U 136 (escort)
HMCS Trentonian (K368) U 1004 (escort)

British Royal Navy
HMS Abelia (K184) - U??? (escort) T5/damaged/sold
HMS Arbutus (K86) - U 136 (escort)
HMS Asphodel (K 56) U 575 (escort)
HMS Bluebell (K80) - U 711 (escort)
HMS Fleur de Lys (K122) - U 206
HMS Gladiolus (K34) - U 553 (escort)
HMS Picotee (K63) - U 568 (escort)
HMS Pink (K 137) - U 988 (escort) damaged/loss
HMS Polyanthus (K47) - U 305 (escort)
HMS Salvia (K97) - U 568 4 Torps Fan
HMS Vervain (K190) - U 1276 (escort)
HMS Zinnia (K98) - U 564 (escort)

French Flower Class
FFL Alysse (K 100) - U 654 (escort)
FFL Mimosa (K11) - U 124 (escort)

Norwegian Flower Class
HNoMS Montbretia (K208) - U 262

These are only successful attacks! They probably tried more often!

__________________________________________________ _______

Edit2: (07/01/16)

Castle Class Corvettes
HMS Hurst Castle (K416) - U 482 (escort)
HMS Denbigh Castle (K696) - U 992 (escort)

------------------------------------------------------------------------------------------

Frigates attacked by German Uboats, but not sunk (damaged beyond repair/all declared loss)

Canadian River Class Frigate
HMCS Chebogue (K317) - U 1227 (escort) (= attacked while assigned to a convoy as escort)
HMCS Magog (K673) - U 1223 (escort)

British River Class Frigate
HMS Cuckmere (K 299) - U 223
HMS Lagan (K 259) - U 270 (escort)
HMS Teme (K458) - U 246/U 315 (escort)

British Captain Class Frigate (ex US Evarts & Buckley)
HMS Goodson (K480) - U 984 (prob. escort)
HMS Bickerton (K466) - U 354 (escort)
HMS Whitaker (K580) - U 483 (escort)
HMS Mounsey (K569) - U 295 (escort)
HMS Affleck (K462) - U 486 (sank HMS Capel (K470) the same day)
HMS Manners (K568) - U 1051 (Hunter Killer)
HMS Redmill (K554) - U 1105 (patrol)
HMS Goodall (K479) - U 286 (escort)

Most have been attacked with G7es.

_________________________________________________

Edit4: (07/03/16)

Frigates directly sunk by German Uboats

Canadian River Class
HMCS Valleyfield (K329) - U 548 (transfer)

British River Class
HMS Itchen (K 227) - U 666 (escort)(Gefallener Engel - Aktungbby)
HMS Tweed (K 250) - U 305 (escort; patrol)
HMS Mourne (K 261) - U 767 (patrol)

Captain Class (ex US Evarts & Buckley)

HMS Blackwood (K313) - U 764 (escort; patrol)
HMS Capel (K470) - U 486 (patrol)
HMS Gould (K476) - U 358 (Hunter Killer)
HMS Bullen (K469) - U 775 (escort;patrol?)

__________________________________________________ ______

Edit3: (07/01/16)

Sloops sunk/attacked by German Uboats

British
HMS Penzance (L28) - U 37 (escort)
HMS Culver (Y 87) - U 105 (escort)
HMS Dundee (L84) - U 48 (escort)
HMS Puffin (L52) - Rammed a German Midget Submarine Seehund (midget torpedoes exploded/damaged/loss)
HMS Stork (L81) - U77 (escort) (Walker's Bittern Class Sloop - damaged/repaired)
HMS Woodpecker (U08) - U 256 (escort)
HMS Chanticleer (U 05) - U 515 (prob. escort) (damaged/loss)
HMS Kite (U87) - U 344 (escort)
HMS Lark (U 11) - U 968 (escort)
HMS Lapwing (U 62) - U 968 again (escort) (other patrol)

Australian
HMAS Parramatta (U44) - U 559 (escort)

__________________________________________________ ______

[sublynx]

Sunk by gunfire!? Now that is quite a surprise! I'll have to look for some more info on those sinkings.

[20000 Leagues]

Thanks for that info Mittelwaechter! I was surprised to see the sinkings by gunfire.

[KaleutKiwi]

Originally Posted by BL!TZKR!EG

Who says that?

EXACTLY!

destroyers are counted in DEF, i spent several days splitting tonnage so that naval tonnage is shown, and recognized!

[Sailor Steve]

On the other hand, American humorist Mark Twain made a saying popular, attributing it to British Prime Minister Benjamin Disraeli: "There are three kinds of lies: Lies, Damned Lies, and Statistics."

The list posted by Mittelwaechter shows 15 small American ships sunk by u-boats. The link he posts says that 33 British destroyers were sunk by "enemy submarines", which would of course include sinkings by the Japanese. We'll include those, because after all they were still submarines. This doesn't include the 37 corvettes lost to all causes. I didn't go through each one, so we'll just say they were all sunk by u-boats.

This gives a total of 85 small warships sunk by submarines, over the course of the war. That's 85 escorts in 5 years 7 months. Eighty-five ships in 67 months. That's one escort sunk every month. That's by all u-boats, not just one. This means that 20000 Leagues is correct - while attacking escorts did happen, it is statistically insignificant. Realistic would be one escort sunk for every five careers. Total. Sinking one escort in every attack, or even every patrol, is not realistic at all.

[Mittelwaechter]

The Germans didn't attack US NAVY before Oct 31st 1941 (USS REUBEN JAMES).

The question was, if it was historically accurate for the Uboats to attack DDs/DEs.
Statistical relevance was not the issue.

Where are the lies?