Another great book; "The U-Boat War In The Atlantic"
 

Written shortly after the war with original documents by Gunther Hessler who was a u-boat skipper and then held BdU staff positions. Three volumes, on the first currently.
Few interesting items:
- Operations didn't go past 15 degrees west until 11/1940.
- Every night attack was to be done on the surface. No scope attacks.
- U-boats "never employed the tactics of approaching the enemy half-submerged, with tanks already flooded" aka decks awash.
- If a convoy was thought able to be attacked two nights in a row, u-boats were forbidden to attack during the day.

I suspect there will be many other items for anyone interested as I've barely started reading it !

Just finished Kretschmer biography, and was surprised about this point too.
But more of the visibility distances at night...he could penetrate convoy surfaced, stand between rows up to 200m to cargos staying invisible...escape escorts quite easily 500m away still invisible!
His favorite tactic was to stand at the rear of convoy, sail up in a row, sink 1 or 2 ships, let the convoy pass his boat until he could sail in other row and rince and repeat!
Many times he didn’t even have to dive for escape. Escorts were almost completely ineffective at this time.
He was just using his U-Boat like a torpedo boat, and was the only one doing like this.
He tried to convert others friends (like Prien and Schepke) to this very successful tactic, but they were not enthusiastic.
Even though it was not recommended tactic, Doenitz was ok with it, as far as results were there.

No need to say it’s not doable in game...unless giving a hard visibility handicap at night to AIs

Yes, it is remarkable ! The dive that lead to his capture (asdic found him right away) wasn't his order and he wasn't happy about it.
Also, that battle that led to his capture and the deaths of Prien and Schepke was the first in which radar was involved.

:up: :salute:

Yes, but to simulate the same thing in the game, we have to attack with decks awash, until late 40/early 41.


I also read Kretschmer biography, a bit of bad luck also involving his capture. The deck officer (can not remember if was a new IWO) didn't carry out his normal order when detecting a destroyer and the destroyer (the one that attacked him or one of) was picking up the survivors of Schepke boat.



Kretschmer IWO, A. Schnee also did similar night attack tactic, attacking the last ships of a convoy, allowing the escort to pass by them, shooting the torpedoes at target (close range, possible 1,5 km and less) and turning the boat a parallel course and exiting the convoy on a opposite course.

There is a collection of book about famous u-boat commanders, hard cover, A4 or more in size (a tall book) with their biography and war patrols. I have the one about Schnee and there is a image from the log book drawing of the attack.

Not necessarily, if you're meaning to make it harder for an escort to see you. It provides no help in that regard in the game, at least in my experience.

Cmdr could be useful for that matter, meaning increasing Sim Cfg Light Factor value for certain date to date...to blind a little bit more AI eyes at night so you could approach enemy very close staying undetected.

True but its easy enough already in the game to get absurd tonnages without this tactic. :)

This is where almost all U-boat sims have been wrong, you could dive within 30-45 seconds without 'decks awas', with an alert crew. But you would not dive for an attack at night. As Doenitz said, "At night go in surfaced, and get close. They do not see you!".
Destroyers, escorts and corvettes would be seen long before the latter spotted the boat, so evasion from faster ones and running out slow corvettes on the surface was easy. Also a much better situation awareness, of course.
Until 1943 not all escorts had radar, also it often didn't work at all or badly, for various reasons. After this and with several escorts having radar able to triangulate, things of course changed dramatically.

From the very first sims to SH5, up to 1942 they would almost always see you. The best is still SH3 with the GWX or LSH mods..
In SH5 two destroyers found me surfaced in 1940, in rain and dense fog, at night, visibility zero. With 'found' i mean they followed and rammed. Then third mission or so sink five troop transports to get on. Adding one-eyed pirates as a crew and cheesy non-nazis all over the boat. That is basically when i stopped playing and got back to SH3 :D

Yes, the author acknowledges it was a common tactic in other navies (though done via the electric motors not diesel per the game) but the Germans thought it "ill advised".
He doesn't state what was meant by that but I wouldn't be surprised if it was meant the increased speed, etc. available to evade on the surface and partially flooded tanks would negate that option.
Could also be trim keeping problems and the uncontrolled crash dive those could cause irl.
Hmmm......maybe the old crash dive blues bug wasn't a bug after all ! :haha: (nah, it was).

I do not understand what you (or the author?) mean(s) with "other navies .. used electric, not Diesel".. surfaced with E-engines? :hmmm:
There was of course the option to add the electric motors to the Diesels, to go at 22 or so knots for a very short time, but i never saw this mentioned in surface attack reports.

And thanks for the book advice, will look out for it! :up:

When decks awash was used the boat was powered then by its electric motors vs. its diesels.
That's not possible in the game, i.e., is all. The author didn't state this; that was only me. :)

Another idea to simulate his tactic. NYGM has various visual nodes for different items merchant ships "crews" being one.
Could import that node to one's install if not using NYGM, adjust the settings there, and simulate this tactic while still keeping the escorts spotting abilities as is. (some SH3 versions have the same spotting ability used by all units so blinding the merchants would also affect the escorts).

^ Ah i see, thanks. But not quite true, they used to indeed go surfaced with decks awash and Diesels running at daytime and calm weather, in the mediterranean (to evade air attacks by faster diving), but not during attacks or at night – afaik.
Diesels running at half speed would easily be able to press out the exhaust fumes from the outboard exhaust orifices, even if the deck was awash. The intakes were mounted at upper tower level (those openings with the grids).
I take it decks awash is a perfect recipe for disaster during an attack, when the bow and tower undercut waves in any but very calm weather. This would be especially bad for the larger type IX boats, their deck acting as a gigantic dive plane :hmmm:

:up: Thanks for the info. ! I wonder if the relative calmness of the Med allowed that (diesels) vs. elsewhere ?

I am talking from memory and I may be confusing old threads: I remember reading here that escorts detection parameters, in game, of us (u-boat) have also to do with speed and heigh. Again, I am not sure of this.


In my game, GWX3+several mods, until mid 41 or sometimes later, with a calm sea state, decks awash and going like 3 to 5 knots, I could get very close to the convoy and sometimes the lateral escorts do pass like 800m near me with out changing course to attack me.

I also experience the opposite, thinking that it is going to be a nice attack and the sky is sudden full of star shells and the escorts are coming to attack.

Speed, weather, wave height, profile affect detection among other items. I've never heard sub height doing so, if that is what you mean.
I do recall that even the tiny snorkel head was treated by the game same size as the entire sub in terms of detection. Don't know if that was changed over the years.
I've had similar results as your examples both awash and not fwiw. :)

I see. I never manage to get so near a convoy with out decks awash. Well, back to patrol, want to experiment to see if I can get them with out that technique.

There are so many other variables involved my examples could be totally unrelated to whether its used or not for that matter.
For sure post any results you get. :up:

Of course. I am now in a 42 campaign. My late 43 Type IX was down the ocean...:dead:.
I will take some time to get to the early years.



In sake of books, two I have read: No Room for Mistakes: British and Allied Submarine Warfare, 1939–1940 and The Gathering Storm: The Naval War in Northern Europe, September 1939-April 1940.



Both of the same author and quite good books about the first year of the war and what come up from it.