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Caeles
03-29-2005, 05:36 PM
Torpedoes: A Primer. (V1.3)

Everyone,

After spending a couple days looking over the forums, I have decided to write a summarized introduction into the world of German WWII torpedoes for some of our newer players. By doing so, it is my hope that both new and experienced players alike may learn something new and interesting that aids them on their wartime patrols.

The information listed here is by no means all inclusive and if you have additional information or comments to add, then please do. If you find any errors, please feel free to bring them to my attention. I will bundle all additional commentary made by fellow players into the guide and cite them as required.

I have also limited the selection of torpedoes in this list to the ones modeled in Silent Hunter III. If I missed one, be sure to let me know.

Best,
Caeles

German Torpedo Designations

Diameter:

€˜F€ = 450mm
€˜G€ = 500 or 533mm
€˜H€ = 600mm
€˜J€ = 700mm

Length: Rounded to the nearest meter.

Propulsion:

€˜a€ = Wet Heater
€˜e€ = Electric
€˜u€ = Hydrogen Peroxide

Modifications:

Modifications (improvements, adjustments, etc) were usually, but not always, denoted by €˜T€ numbers.

Example:

The G7a T1 torpedo was 533mm in diameter (G), about seven meters long (7), used a wet heater propulsion system (a), and was the first of its type (T1).

German Torpedoes

Type: G7a T1 (T-I)
Propulsion: Decahydronaphthalene (Decalin) Wet Heater
Range/Speed: 6000m @ 44 knots, 8000m @ 40 knots, 14000m @ 30 knots
Warhead: 280kg HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

This was the standard pre-war issued torpedo that found its way onto many U-Boats at the beginning of WWII. The weapon itself was actually relatively reliable in a historical sense but, because of its propulsion system, vented gas to the surface during its run. While the resulting trail of bubbles was difficult to see at night, alert watchmen on both merchant ships and escorts quickly learned to recognize the trail during daylight hours.

As such, German doctrine strongly recommended the torpedoes usage only during nighttime hours or when visibility suffered due to rain, fog, etc.

Additional Comments:

€œMost of the attacks I make are during the night. Because of this and the fact that I can adjust the speed settings on the G7a T1, it has become my torpedo of choice for the beginning of the war and during any nighttime operation. I am also unsure as to their €˜actual€ ranges. Some sources use the ranges I have. Other sources (including the Silent Hunter Manual) use smaller ranges. I have yet to actually see which one is right.€ €" Caeles

Type: G7e T3 (T-III)
Propulsion: Electric Motor
Range/Speed: 5000m @ 30 knots (Preheated), 3000m @ 28 knots (Not Preheated)
Warhead: 280kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

Almost identical to the G7a T1, the T3 utilized an electric motor for its power plant that enabled the torpedo to move through the water without the aforementioned gas bubbles that plagued the T1. While this made the torpedo far more useful during daytime operations, the weapon was manufactured with several atrocious design flaws.

When the T2 first saw combat action it performed very poorly. To begin with, the weapon would (most of the time) run at a depth far deeper than that which the weapons officer on board the U-Boat set. This resulted in the annoying tendency of torpedoes to go sailing right under the target, rather than actually hitting it.

On a second note, the magnetic detonation pistol was designed poorly and, because of the unique magnetic environment in €˜Zone O€ (off the coast of Norway), many U-Boats had to deal with premature detonations.

Thankfully, Admiral Donitz set out immediately to rectify the situation and assist his brave and daring U-Boat crews. While the German Torpedo Department had originally noted that €˜Zone O€ would have little (if any) effect on the magnetic firing pistols, they were soon proved wrong. After a conference with both the Torpedo Department and Naval High Command, Donitz concluded that the magnetic interference from the fjords did, after all, affect the magnetic torpedoes.

A commission was setup to investigate how this colossal design failure went unchecked and, not surprisingly, the commission held the Torpedo Department responsible. They found that while the Torpedo Department designed, built, and shipped their product, they failed to actually test it. As a result, a large number of responsible personnel at the Torpedo Experimental Institute were court-martialed and assigned prison sentences. While the commission found the reason for premature detonation, the faulty depth keeping issue eluded them.

At one point, the crew of U-94 decided to take a little extra initiative and began thoroughly examining their torpedo load-out of G7e T3s. After some careful research the crew found an excess pressure variance in the torpedoes€ balance chambers. These chambers, connected to the weapon€s hydrostatic valve, were responsible for depth keeping. It would appear that while the weapon functioned more or less perfectly on the surface (neutral pressure), it performance dropped considerably while the submarine was submerged (especially if said submarine had been submerged for quite some time).

The balance chambers were, unfortunately, not designed to be air tight. While underwater a U-Boat makes small periodic bursts of compressed air into the hull. This compression accumulated over time and seeped into the balance chambers on the torpedo. Thus, when the weapon was launched, it €˜thought€ it was at a much different starting depth. This resulted in the torpedo sailing downward and completely missing its intended target.

During the Norwegian Campaign it is estimated that as many as 30-35% of G7e T3s used in combat failed to detonate, detonated prematurely, or ran themselves too deep. After the Norwegian Campaign, both the magnetic firing pistol and the issue with the internal balance chambers were rectified.

In 1942 Germany rolled out the newly improved T3a which increased the weapon€s maximum range to 7500m at 30 knots.

Additional Comments:

€œIt€s handy during the day, possesses wonderful wake less movement, and explodes spectacularly. When it works. Later in the war, after most of its serious design flaws are corrected, its an excellent weapon.€ - Caeles

Type: G7a T1 (T-I) or G7e T3 (T-III) FaT
Propulsion: T1 - Decahydronaphthalene (Decalin) Wet Heater / T3 - Electric Motor
Range/Speed: T1 - 6000m @ 44 knots, 8000m @ 40 knots, 14000m @ 30 knots / T3 - 5000m @ 30 knots (Preheated), 3000m @ 28 knots (Not Preheated)
Warhead: 280kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

The FaT torpedo was designed to increase the probability of a strike inside a convoy by allowing the weapon to €˜intelligently€ move about in a preordained searching pattern.

When fired, the FaT torpedo would continue along its initial run route in the hopes of hitting a target. If it failed to hit anything, it would continue moving along its starting trajectory for another 800 or 1600 meters (selectable by the weapons officer) before executing a one hundred and eighty degree turn in the opposite direction. The weapon would continue in this manner until it either struck a target or ran out of power.

Additional Comments:

€œIts fancy, but I have never had a run of good luck with them and as such prefer to rest my faith in the regular G7a T1 and G7e T3 In fact, in one engagement, I accidentally managed to let my U-Boat drift into the FaT€s course. Yeah. Well. That didn€t go so well.€ €" Caeles

Type: G7a T1 (T-I) or G7e T3 (T-III) LuT
Propulsion: T1 - Decahydronaphthalene (Decalin) Wet Heater / T3 - Electric Motor
Range/Speed: T1 - 6000m @ 44 knots, 8000m @ 40 knots, 14000m @ 30 knots / T3 - 5000m @ 30 knots (Preheated), 3000m @ 28 knots (Not Preheated)
Warhead: 280kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

This weapon is almost identical to the FaT version with the addition of a second gyroscope. And, as stated in the Silent Hunter Manual, only around seventy of these weapons ever made it out of the production plant.

Additional Comments:

€œYay. An extra gyroscope.€ €" Caeles

Type: G7e T5 (T-V)
Propulsion: Electric Motor
Range/Speed: 5700m @ 24 knots
Warhead: 274kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 400m
Description:

As the Allies made advancement after advancement in the arena of anti-submarine warfare (ASW), the Germans desperately needed a way to confront Allied escorts or at least distract them long enough to get at the convoy.

In its original version (the T4 or T-IV if you like your roman numerals) this weapon was designed as a €˜wake homing€ weapon. Once launched it would travel a distance of four hundred meters before arming itself and search for the loudest source of sound. Unfortunately, the weapon was ridiculously slow and possessed no magnetic detonator. This made the torpedo almost useless in practical combat.

Realizing they had made a mistake, the Torpedo Department quickly relieved the T4 from duty and replaced it with the much more commonly used T5.

The T5 was envisioned by both the Torpedo Department and Navel High Command as an answer to Allied escorts. The homing system on the weapon itself was primitive and required a fairly loud source of sound to track. Although some may see this as a limitation, it was argued that the weapon€s primary usage would be against Allied escorts; and escorts, being the rather noisy things that they are, provided more than enough sound to attract the interest of the weapon€s homing system.

Unfortunately, the Allies very quickly determined what the T5 (or €œGnat€ as they called it) was and how it operated. Thus they invented the €˜Foxer€ device. The Foxer was strung out behind a warship and made an obnoxious racket underwater in order to draw the T5 towards it. The homing system, being primitive, was unable to distinguish between the engine sounds of the escort and the Foxer.

It should also be noted that the weapon did, from time to time, try (and sometimes succeed) in acquiring the U-Boat as its target. Naturally, this was extremely inconvenient for the crew and at least two U-Boats (U-972 and U-377) are suspected to have died at the hands of their own T5 torpedo. It was standard practice to make oneself as quiet as possible once the weapon was launched in order to avoid such problems.

Historically, the weapon was not all together too successful. However, it paved the way for modern acoustic torpedoes (both passive and active) that are in use throughout the world today.

Additional Comments:

€œOnce this thing becomes available, I use it against escorts with reckless abandon. Thus far I have never had one of them double back on me and they would appear to hit enough to make them worth firing in the first place. Although the Allies historically began using the Foxer shortly after the T5€s debut, I am unsure as to whether or not the Foxer is modeled in the game. € €" Caeles

Caeles
03-29-2005, 05:36 PM
Torpedoes: A Primer. (V1.3)

Everyone,

After spending a couple days looking over the forums, I have decided to write a summarized introduction into the world of German WWII torpedoes for some of our newer players. By doing so, it is my hope that both new and experienced players alike may learn something new and interesting that aids them on their wartime patrols.

The information listed here is by no means all inclusive and if you have additional information or comments to add, then please do. If you find any errors, please feel free to bring them to my attention. I will bundle all additional commentary made by fellow players into the guide and cite them as required.

I have also limited the selection of torpedoes in this list to the ones modeled in Silent Hunter III. If I missed one, be sure to let me know.

Best,
Caeles

German Torpedo Designations

Diameter:

€˜F€ = 450mm
€˜G€ = 500 or 533mm
€˜H€ = 600mm
€˜J€ = 700mm

Length: Rounded to the nearest meter.

Propulsion:

€˜a€ = Wet Heater
€˜e€ = Electric
€˜u€ = Hydrogen Peroxide

Modifications:

Modifications (improvements, adjustments, etc) were usually, but not always, denoted by €˜T€ numbers.

Example:

The G7a T1 torpedo was 533mm in diameter (G), about seven meters long (7), used a wet heater propulsion system (a), and was the first of its type (T1).

German Torpedoes

Type: G7a T1 (T-I)
Propulsion: Decahydronaphthalene (Decalin) Wet Heater
Range/Speed: 6000m @ 44 knots, 8000m @ 40 knots, 14000m @ 30 knots
Warhead: 280kg HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

This was the standard pre-war issued torpedo that found its way onto many U-Boats at the beginning of WWII. The weapon itself was actually relatively reliable in a historical sense but, because of its propulsion system, vented gas to the surface during its run. While the resulting trail of bubbles was difficult to see at night, alert watchmen on both merchant ships and escorts quickly learned to recognize the trail during daylight hours.

As such, German doctrine strongly recommended the torpedoes usage only during nighttime hours or when visibility suffered due to rain, fog, etc.

Additional Comments:

€œMost of the attacks I make are during the night. Because of this and the fact that I can adjust the speed settings on the G7a T1, it has become my torpedo of choice for the beginning of the war and during any nighttime operation. I am also unsure as to their €˜actual€ ranges. Some sources use the ranges I have. Other sources (including the Silent Hunter Manual) use smaller ranges. I have yet to actually see which one is right.€ €" Caeles

Type: G7e T3 (T-III)
Propulsion: Electric Motor
Range/Speed: 5000m @ 30 knots (Preheated), 3000m @ 28 knots (Not Preheated)
Warhead: 280kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

Almost identical to the G7a T1, the T3 utilized an electric motor for its power plant that enabled the torpedo to move through the water without the aforementioned gas bubbles that plagued the T1. While this made the torpedo far more useful during daytime operations, the weapon was manufactured with several atrocious design flaws.

When the T2 first saw combat action it performed very poorly. To begin with, the weapon would (most of the time) run at a depth far deeper than that which the weapons officer on board the U-Boat set. This resulted in the annoying tendency of torpedoes to go sailing right under the target, rather than actually hitting it.

On a second note, the magnetic detonation pistol was designed poorly and, because of the unique magnetic environment in €˜Zone O€ (off the coast of Norway), many U-Boats had to deal with premature detonations.

Thankfully, Admiral Donitz set out immediately to rectify the situation and assist his brave and daring U-Boat crews. While the German Torpedo Department had originally noted that €˜Zone O€ would have little (if any) effect on the magnetic firing pistols, they were soon proved wrong. After a conference with both the Torpedo Department and Naval High Command, Donitz concluded that the magnetic interference from the fjords did, after all, affect the magnetic torpedoes.

A commission was setup to investigate how this colossal design failure went unchecked and, not surprisingly, the commission held the Torpedo Department responsible. They found that while the Torpedo Department designed, built, and shipped their product, they failed to actually test it. As a result, a large number of responsible personnel at the Torpedo Experimental Institute were court-martialed and assigned prison sentences. While the commission found the reason for premature detonation, the faulty depth keeping issue eluded them.

At one point, the crew of U-94 decided to take a little extra initiative and began thoroughly examining their torpedo load-out of G7e T3s. After some careful research the crew found an excess pressure variance in the torpedoes€ balance chambers. These chambers, connected to the weapon€s hydrostatic valve, were responsible for depth keeping. It would appear that while the weapon functioned more or less perfectly on the surface (neutral pressure), it performance dropped considerably while the submarine was submerged (especially if said submarine had been submerged for quite some time).

The balance chambers were, unfortunately, not designed to be air tight. While underwater a U-Boat makes small periodic bursts of compressed air into the hull. This compression accumulated over time and seeped into the balance chambers on the torpedo. Thus, when the weapon was launched, it €˜thought€ it was at a much different starting depth. This resulted in the torpedo sailing downward and completely missing its intended target.

During the Norwegian Campaign it is estimated that as many as 30-35% of G7e T3s used in combat failed to detonate, detonated prematurely, or ran themselves too deep. After the Norwegian Campaign, both the magnetic firing pistol and the issue with the internal balance chambers were rectified.

In 1942 Germany rolled out the newly improved T3a which increased the weapon€s maximum range to 7500m at 30 knots.

Additional Comments:

€œIt€s handy during the day, possesses wonderful wake less movement, and explodes spectacularly. When it works. Later in the war, after most of its serious design flaws are corrected, its an excellent weapon.€ - Caeles

Type: G7a T1 (T-I) or G7e T3 (T-III) FaT
Propulsion: T1 - Decahydronaphthalene (Decalin) Wet Heater / T3 - Electric Motor
Range/Speed: T1 - 6000m @ 44 knots, 8000m @ 40 knots, 14000m @ 30 knots / T3 - 5000m @ 30 knots (Preheated), 3000m @ 28 knots (Not Preheated)
Warhead: 280kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

The FaT torpedo was designed to increase the probability of a strike inside a convoy by allowing the weapon to €˜intelligently€ move about in a preordained searching pattern.

When fired, the FaT torpedo would continue along its initial run route in the hopes of hitting a target. If it failed to hit anything, it would continue moving along its starting trajectory for another 800 or 1600 meters (selectable by the weapons officer) before executing a one hundred and eighty degree turn in the opposite direction. The weapon would continue in this manner until it either struck a target or ran out of power.

Additional Comments:

€œIts fancy, but I have never had a run of good luck with them and as such prefer to rest my faith in the regular G7a T1 and G7e T3 In fact, in one engagement, I accidentally managed to let my U-Boat drift into the FaT€s course. Yeah. Well. That didn€t go so well.€ €" Caeles

Type: G7a T1 (T-I) or G7e T3 (T-III) LuT
Propulsion: T1 - Decahydronaphthalene (Decalin) Wet Heater / T3 - Electric Motor
Range/Speed: T1 - 6000m @ 44 knots, 8000m @ 40 knots, 14000m @ 30 knots / T3 - 5000m @ 30 knots (Preheated), 3000m @ 28 knots (Not Preheated)
Warhead: 280kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 300m
Description:

This weapon is almost identical to the FaT version with the addition of a second gyroscope. And, as stated in the Silent Hunter Manual, only around seventy of these weapons ever made it out of the production plant.

Additional Comments:

€œYay. An extra gyroscope.€ €" Caeles

Type: G7e T5 (T-V)
Propulsion: Electric Motor
Range/Speed: 5700m @ 24 knots
Warhead: 274kg of either TNT (Trinitrotoluene) or HND (Hexanitrophenylamine)
Minimum Distance to Arm: 400m
Description:

As the Allies made advancement after advancement in the arena of anti-submarine warfare (ASW), the Germans desperately needed a way to confront Allied escorts or at least distract them long enough to get at the convoy.

In its original version (the T4 or T-IV if you like your roman numerals) this weapon was designed as a €˜wake homing€ weapon. Once launched it would travel a distance of four hundred meters before arming itself and search for the loudest source of sound. Unfortunately, the weapon was ridiculously slow and possessed no magnetic detonator. This made the torpedo almost useless in practical combat.

Realizing they had made a mistake, the Torpedo Department quickly relieved the T4 from duty and replaced it with the much more commonly used T5.

The T5 was envisioned by both the Torpedo Department and Navel High Command as an answer to Allied escorts. The homing system on the weapon itself was primitive and required a fairly loud source of sound to track. Although some may see this as a limitation, it was argued that the weapon€s primary usage would be against Allied escorts; and escorts, being the rather noisy things that they are, provided more than enough sound to attract the interest of the weapon€s homing system.

Unfortunately, the Allies very quickly determined what the T5 (or €œGnat€ as they called it) was and how it operated. Thus they invented the €˜Foxer€ device. The Foxer was strung out behind a warship and made an obnoxious racket underwater in order to draw the T5 towards it. The homing system, being primitive, was unable to distinguish between the engine sounds of the escort and the Foxer.

It should also be noted that the weapon did, from time to time, try (and sometimes succeed) in acquiring the U-Boat as its target. Naturally, this was extremely inconvenient for the crew and at least two U-Boats (U-972 and U-377) are suspected to have died at the hands of their own T5 torpedo. It was standard practice to make oneself as quiet as possible once the weapon was launched in order to avoid such problems.

Historically, the weapon was not all together too successful. However, it paved the way for modern acoustic torpedoes (both passive and active) that are in use throughout the world today.

Additional Comments:

€œOnce this thing becomes available, I use it against escorts with reckless abandon. Thus far I have never had one of them double back on me and they would appear to hit enough to make them worth firing in the first place. Although the Allies historically began using the Foxer shortly after the T5€s debut, I am unsure as to whether or not the Foxer is modeled in the game. € €" Caeles

dquock
03-29-2005, 05:44 PM
Very nice information! Thank you!

A minor question: It shows the G7a T1 with the range and speeds as 6000m @ 44 knots, 8000m @ 40 knots, and 1400m @ 30 knots.

Is that correct? I thought the range decreases at higher speeds?

Caeles
03-29-2005, 05:47 PM
Yes. Yes it does, Dquock. I am afraid that was a typo. Allow me to correct it... :-)

dquock
03-29-2005, 06:00 PM
I really like it! I'm an armchair submarine buff, starting back in Silent Service on my Apple IIe. =) I find this information (and history in general) very fascinating. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Thanks again!