LUT or FAT?

[Snestorm]

What, if any, advantages does a LUT torpedo hold over a FAT torpedo?

The 1944 torpedo loadout order states that Type VIIC & IXC "LUT boats" would carry a majority of LUT torpedoes, while Type VIIC & IXC "non LUT boats" would be loaded with a majority of FAT torpedoes.

Can anybody shed some light on what factors qualify a boat as a "LUT boat" or "Non LUT boat"?

[Jimbuna]

FAT Federapparat or Flächenabsuchender Torpedo (spring device or area searching torpedo), a mechanical device changes the torpedo's course over time so that it runs up- and down on parallel lines of 800 or 1600 m length

LUT Lageunabhängiger Torpedo (bearing independent torpedo), changes the torpedo's course to a preset heading directly after launch, so the launching platform (only submarines) can fire such torpedoes at targets without changing its own course.

http://en.wikipedia.org/wiki/List_of_World_War_II_torpedoes_of_Germany

http://www.navweaps.com/Weapons/WTGER_WWII.htm

http://www.uboataces.com/weapon-torpedo.shtml

http://en.wikipedia.org/wiki/G7e_torpedo

[Daniel Prates]

LUT Lageunabhängiger Torpedo (bearing independent torpedo), changes the torpedo's course to a preset heading directly after launch, so the launching platform (only submarines) can fire such torpedoes at targets without changing its own course.

Doesn't that basically describes every single torpedo able of being directed by a gyroangle input?

[derrinurban]

The GWX manual (pages 97 and 99) give descriptions and diagrams for how the LUT and FaT work.

[King_Zog]

The LUT is basically a more sophisticated version of the FAT which can be programmed with a second gyro angle which initiates after it completes its straight run and just before it starts its ladder pattern.

This is best explained with a diagram, if you follow this link and scroll to the middle of the document (the section concerning torpedos) you'll see the difference between FATs and LUTs explained in detail with pictures.

http://www.uboatarchive.net/KTBNotesArmamentCumulativeEdition.htm

It's from an allied wartime intelligence report so some of the information in the document is speculative (distinctions are made in the text between what is believed to be fact and speculation, makes for interesting reading), although the description of FATs and LUTs is pretty much bang on as far as I know.

edit: And yeah like derrinurban said... it's in the GWX manual too.........

[Snestorm]

FAT Federapparat or Flächenabsuchender Torpedo (spring device or area searching torpedo), a mechanical device changes the torpedo's course over time so that it runs up- and down on parallel lines of 800 or 1600 m length

LUT Lageunabhängiger Torpedo (bearing independent torpedo), changes the torpedo's course to a preset heading directly after launch, so the launching platform (only submarines) can fire such torpedoes at targets without changing its own course.

http://en.wikipedia.org/wiki/List_of_World_War_II_torpedoes_of_Germany

http://www.navweaps.com/Weapons/WTGER_WWII.htm

http://www.uboataces.com/weapon-torpedo.shtml

http://en.wikipedia.org/wiki/G7e_torpedo

Thanks. navweaps.com was loaded with good info.

[Snestorm]

The LUT is basically a more sophisticated version of the FAT which can be programmed with a second gyro angle which initiates after it completes its straight run and just before it starts its ladder pattern.

This is best explained with a diagram, if you follow this link and scroll to the middle of the document (the section concerning torpedos) you'll see the difference between FATs and LUTs explained in detail with pictures.

http://www.uboatarchive.net/KTBNotesArmamentCumulativeEdition.htm

It's from an allied wartime intelligence report so some of the information in the document is speculative (distinctions are made in the text between what is believed to be fact and speculation, makes for interesting reading), although the description of FATs and LUTs is pretty much bang on as far as I know.

edit: And yeah like derrinurban said... it's in the GWX manual too.........

And, thank you.
This was just the information I was seeking.
Bookmarked it too.

[sublynx]

Can anybody shed some light on what factors qualify a boat as a "LUT boat" or "Non LUT boat"?

This is an interesting question and I tried to find some info on the differences of "FAT boats" and "LUT boats". I couldn't find anything on the internet. However I found a mention that FAT and LUT torpedoes are discussed in a book about German torpedoes:

http://www.amazon.de/Torpedos-deutschen-U-Boote-Eigenschaften-Marine-Torpedos/dp/3813208427

Maybe this book could help. It is in German though (it's only 9,95 euroes, I'm thinking about buying it myself, though my skills in German are pretty meager). My guess is that there was not enough LUT torpedoes for every boat and that they gave LUT torpedoes to boats that they wanted to have extra maneuverability in their attack approaches.

[Snestorm]

This is an interesting question and I tried to find some info on the differences of "FAT boats" and "LUT boats". I couldn't find anything on the internet. However I found a mention that FAT and LUT torpedoes are discussed in a book about German torpedoes:

http://www.amazon.de/Torpedos-deutschen-U-Boote-Eigenschaften-Marine-Torpedos/dp/3813208427

Maybe this book could help. It is in German though (it's only 9,95 euroes, I'm thinking about buying it myself, though my skills in German are pretty meager). My guess is that there was not enough LUT torpedoes for every boat and that they gave LUT torpedoes to boats that they wanted to have extra maneuverability in their attack approaches.

Thanks for looking, and the link.
(The german language doesn't work for me either.)

I'm wondering if perhaps captain & key crew members would have to be specialy qualified in the complexities of the LUT torpedo. There seems to be much to learn.

I'm somewhat torn between being anxiouse to try them, and fearful of not understanding how to properly use them. 1944 is not a forgiving time for experimenting. Therefor, should my boat survive for another patrol, I think I'll stick with the simpler FATs. Even they seem to consume much ekstra time.

[washishu]

My understanding—although I don't know it to be 100% fact—is that the additional information required for programmable torpedoes required modifications to the TDC. It may be that 'LUT boats' or 'FAT boats' were boats that had had this modification.

[sublynx]

My understanding—although I don't know it to be 100% fact—is that the additional information required for programmable torpedoes required modifications to the TDC. It may be that 'LUT boats' or 'FAT boats' were boats that had had this modification.

This sounds likely. The TDC must have been changed and that might have taken some time.

[Randomizer]

The book Type VII U-Boats by Robert Stern states that physical changes were required to both the attack computer and torpedo tube to accommodate FaT's. Further modifications were needed to use LuT's and by July 1944 some fifty boats had been refitted for them. The implication seems to be that the modifications were exclusive and a LuT boat could not necessarily launch FaT's or vice versa.

SH3 allows you to use both types interchangably and I have had good success using them against convoys late in the war and avoiding counter-attacks.

[Snestorm]

My understanding—although I don't know it to be 100% fact—is that the additional information required for programmable torpedoes required modifications to the TDC. It may be that 'LUT boats' or 'FAT boats' were boats that had had this modification.

Wow!
Thank you for the info, which is quite useful.

[Snestorm]

The book Type VII U-Boats by Robert Stern states that physical changes were required to both the attack computer and torpedo tube to accommodate FaT's. Further modifications were needed to use LuT's and by July 1944 some fifty boats had been refitted for them. The implication seems to be that the modifications were exclusive and a LuT boat could not necessarily launch FaT's or vice versa.

SH3 allows you to use both types interchangably and I have had good success using them against convoys late in the war and avoiding counter-attacks.

And many thanks to you too, sir.
Real good knowledge for bringing up the "realism" that ekstra notch.
(Also nice to know, that it's OK to stick with FaT, and avoid LuT.)

[Snestorm]

This sounds likely. The TDC must have been changed and that might have taken some time.

And you . . .
Have reached the point in your campaign, where you can apply this wealth of knowledge.

(I'll have to wait . . . , again.)

[sublynx]

And you . . .
Have reached the point in your campaign, where you can apply this wealth of knowledge.

(I'll have to wait . . . , again.)

Yeah, I do have these two FAT torpedoes on my boat right now, but for two patrols now I haven't been able to find a convoy. However I am now ordered to patrol a grid I'm pretty sure will finally give me the chance of trying these torpedoes.

I'm sure you will have a chance again too, in no time. With a type IX and the long patrol times, it won't take too long!

[Gerald]

Yeah, I do have these two FAT torpedoes on my boat right now, but for two patrols now I haven't been able to find a convoy. However I am now ordered to patrol a grid I'm pretty sure will finally give me the chance of trying these torpedoes.

I'm sure you will have a chance again too, in no time. With a type IX and the long patrol times, it won't take too long! Right...you will soon find that they have good use areas, not only in convoys but also on the solo ship

[sublynx]

I read Silent Hunter III manual and it stated on page 52 that only about 70 LUT torpedoes were ever made. If this is true it would be quite alright not to use LUT's at all. If one wants to keep one's playing historically oriented.

[Gerald]

Yes!

[Snestorm]

I read Silent Hunter III manual and it stated on page 52 that only about 70 LUT torpedoes were ever made. If this is true it would be quite alright not to use LUT's at all. If one wants to keep one's playing historically oriented.

Good information, and good news for me. Thanks!

[Gerald]

I prefer FAT, in my experience, when I have GWX and its possibilities, but that's me, :DL

[sublynx]

I found BdU's orders about FaT torpedoes from U-boat archive:

http://www.uboatarchive.net/BDUKTB30323.htm


The page is quite long. Search for:

B.d.U. Standing Order 306
Method of using FAT torpedoes

and:

Operational release of FAT G 7E

and:
Permanent Order No. 40
Equipment with Torpedoes

There's some nice information there, if one wants to keep one's playing as close to historical as possible. There's also exact orders about the impact pistol settings for the torpedoes.

[Fish In The Water]

I found BdU's orders about FaT torpedoes from U-boat archive:

http://www.uboatarchive.net/BDUKTB30323.htm

Thanks for the link! :salute:

[Snestorm]

I found BdU's orders about FaT torpedoes from U-boat archive:

http://www.uboatarchive.net/BDUKTB30323.htm


The page is quite long. Search for:

B.d.U. Standing Order 306
Method of using FAT torpedoes

and:

Operational release of FAT G 7E

and:
Permanent Order No. 40
Equipment with Torpedoes

There's some nice information there, if one wants to keep one's playing as close to historical as possible. There's also exact orders about the impact pistol settings for the torpedoes.

Wow!
Great find.
Many, many thanks.