SUBSIM Radio Room Forums - A Guide to Historical TWoS Gameplay

This is a quick guide I’ve been working on for people who want to ensure that their TWoS gameplay is as historically accurate as possible.

It may change as TWoS is updated and new information comes to light.

Feel free to point out any mistakes I make :salute:

Radio Reports

The BdU would expect you to send a status report at least every 24 hours. These regular reports were vital to the wolfpack tactic, as it allowed Doenitz to know which boats were in a position to attack a convoy, when they were ready to attack, and what their fuel/armament/damage situation was.

When shadowing a convoy, contact reports should be sent more regularly, say every two hours. BdU needed to know if the convoy had changed speed or course, or if any reinforcements had arrived, in order to effectively co-ordinate the wolfpack. More regular reports allowed more accuracy.

U-boats would shadow convoys even when out of torpedoes. For example, U-47 shadowed HX-72 after sighting the convoy while serving as a weather reporting boat, with only one torpedo left aboard. The resulting attack sank 73,000 GRT. U-47 only helped U-99 to sink a dead-in-the-water freighter during the attack, but was arguably the most important participant in the battle thanks to the contact reports.

U-boats also sent contact reports when sighting high value targets, such as capital ships and large cruise liners, though for the most part they seem to have only reported these contacts after an unsuccessful attack, or if they couldn't attack.

Using the radio as much as the real u-boats is dangerous, however. Even before enigma was cracked, the Allies could intercept the outgoing signals, and could even get a rough position. Later in the war, the fact that they could detect AND read the u-boat's signals gave them a huge advantage in hunting them down.

Navigation

The Kiel Canal

Wether or not you should use the Kiel Canal seems to depend on the date. For example, in November and December 1940, U-95 and U-96 moved to the Atlantic via Skagerrak, rather than using the canal:

https://i.imgur.com/wsyZOeK.jpg

https://i.imgur.com/6OT9sHW.jpg

Meanwhile, in March and April 1941, U-98 and U-75 did go through the canal:

https://i.imgur.com/9RA3TtF.jpg

https://i.imgur.com/K3qfKaZ.jpg

Equipment

Torpedoes:

- T I (G7a): The earliest German torpedo design used in WWII, but less common than the TII due to a longer manufacturing process. The largest confirmed amount carried on a type VII u-boat that I could find was four, though other type VIIs may have carried more. It had three range/speed settings - 6km at 44 knots, 8km at 40 knots, and 14km at 30 knots.

These torpedoes could be carried in the external containers, as they had no batteries to maintain.

- T II (G7e): The standard u-boat torpedo at the beginning of WWII. Cheaper and easier to make than the TII, but with a slower maximum speed of 30 knots and shorter range of 5km when pre-heated. Without pre-heating, only 28 knots at 3km could be attained. (In TWoS, maximum range when preheated is 5km, but the speed remains at 28 knots due to how Ubisoft programmed the TDC - a historically accurate speed would result in even a perfect solution missing.

These torpedoes could not be carried in external containers, as this would prevent battery maintenance.

- T III (G7e): An improved T II with British-designed pistols taken from HMS Seal. Entered service in 1942. Pre-heated range was still 5km at 30 knots, with 3km at 28 knots being the “cold” performance.

These torpedoes could not be carried in external containers, as this would prevent battery maintenance.

- T IIIa (G7e): Entering service in mid-1942, this was an improved T III with longer range - 7500m at 30 knots when pre-heated, and 4500m at 28 knots when “cold”. The T III as modelled in TWoS most closely matches the performance of this torpedo.

These torpedoes could not be carried in external containers, as this would prevent battery maintenance.

- T IV (G7es) “Falke”: Seeing service in March 1943 aboard three u-boats (U-221, U-603, and U-758), the T IV was a T IIIa with an acoustic tracker and reduced speed of 20 knots, while keeping the 7500m maximum range. I couldn’t find anything that explicitly confirmed or denied that these torpedoes had to be pre-heated to attain the above performance.

These torpedoes could not be carried in external containers, as this would prevent battery maintenance.

- T V (G7es) “Zaunkönig I”: An improved acoustic torpedo, the T 5 entered service in autumn 1943. Boats were ordered to dive to 60 metres at silent running after launch, to prevent the torpedo from locking on to them. It was faster than the T 4 at 24 knots, but apparently had a shorter maximum range of 5700m. Again, I couldn’t find anything that explicitly confirmed or denied that these torpedoes had to be pre-heated to attain the above performance.

These torpedoes could not be carried in external containers, as this would prevent battery maintenance.

- T XI (G7es) “Zaunkonig II”: A T V with a better acoustic tracker, this torpedo was, in theory, less prone to be fooled by decoys. However, in never saw operational use. Range and speed remained at 5700m at 24 knots. As previously, I couldn’t find anything that explicitly confirmed or denied that these torpedoes had to be pre-heated to attain the above performance.

These torpedoes could not be carried in external containers, as this would prevent battery maintenance.

- T VIII (G7ut): With a speed of 45 knots at 8km, this walther-turbine powered torpedo never saw operational usage, and the ones tested exhibited problems with the detonators.

It’s unclear if these torpedoes could be carried in external containers.

- T I FaT I (G7a): In service at the end of 1942, this was a T I torpedo with the FaT pattern running device.

These torpedoes could be carried in the external containers, as they had no batteries to maintain.

- T III FaT I (G7e): In service at the end of 1942, this was a T III torpedo with the FaT pattern running device.

These torpedoes could not be carried in external containers, as this would prevent battery maintenance.

- T I LuT I (G7a): In service at the end of the war, this was a T I torpedo with the LuT pattern running device.

These torpedoes could be carried in the external containers, as they had no batteries to maintain.

Radars:

- FuMO 29: Developed in 1941, this ineffective radar was historically only fitted to three type IX-C u-boats (U-156, U-157, and U-158).

- FuMO 30: The standard u-boat radar from late 1942 onwards, its use was unpopular with captains, who feared it would give away their position.

- FuMO 61: An improved radar designed in 1943 and introduced in March 1944.

- FuMO 65: A further improvement of the FuMO 61, the FuMO 65 was historically only fitted to type XXI u-boats.

Radar detectors:

- FuMB 1 Metox: Beginning service in August 1942, this was a basic radar detector that could pick up transmissions from 1.5m ASV radars, but also Luftwaffe radio beacons from as far as 80km away.

- FuMB 10 Borkum: A stopgap after the Metox was deemed obsolete, the Borkum saw use from November 1943 to the end of the war.

- FuG 350 Naxos I: Beginning service in September 1943, the Naxos could detect the new 10cm British ASV radars.

- FuMB 26 Tunis: Beginning service in May 1944, and often installed alongside the Naxos, the Tunis could detect the 3cm American radars.

Conning towers:

- Enlarged type VIIB Conning: Installed on all surviving type VII-B u-boats from December 1939 - February 1940, this conning tower incorporated an improved spray deflector and room for an AA gun.

- VIIC Turm II: With installation on u-boats starting in December 1942, the turm II provided room for a second AA gun.

- VIIC/41 Turm IV: In March-May 1943, type VII u-boats began being modified with the turm IV. This provided room for two 20mm mounts (seemingly always in the zwilling configuration) and a quad 20mm or single 37mm mount. By at least December 1943, the automatic 37mm M42 cannon began seeing use on the turm IV. No U-boat was permitted to go on patrol without a turm IV from August 1943 onwards.

Sources:

When two sources contradict each other, I’ve gone with the source I believe to be more trustworthy.

Radio reports:

- https://uboat.net/ops/convoys/convoys.php?convoy=HX-72

- https://uboat.net/allies/merchants/ship/542.html

Torpedoes:

- https://uboat.net/technical/torpedoes.htm

- https://en.m.wikipedia.org/wiki/G7e_torpedo

- https://books.google.com.au/books?id...ternal&f=false

- https://uboat.net/forums/read.php?20,84419,84477

- https://en.m.wikipedia.org/wiki/List...oes_of_Germany

- https://uboat.net/boats/u589.htm

- https://uboat.net/allies/merchants/ship/981.html

Radars:

- https://uboat.net/technical/radar.htm
- https://en.m.wikipedia.org/wiki/FuG_...1_Hohentwiel_U

Radar detectors:

- https://uboat.net/technical/detectors.htm
- http://www.uboataces.com/radar-warning.shtml

Conning towers:

- https://amp.rokket.biz/docs/vii_modifications.pdf