Kriegsmarine Torpedo propeller

[Jesse]

Dear all.

Greetings from Denmark! I found this forum while searching for info on torpedo propellers. In 2007 I bought the upper propeller and a few month ago I bought the lower one. They seems to be a pair. There is no sign at all on the small one but on the bigger one (which is like Jesse's) there is a 15031 from the cast forme and a "89" stamped in the metal. Now I need the rest of the torpedo! Just joking - but I thought you would like to see the pair. I have "a few" more normal propellers but I could not resist to buy these two ones.

Best season greetings to all!

Toke

http://www.norbyhus.dk/

Hallo Norby,

Can you tell me about your torpedo propellor. Do you know if it was made by Norway ? Also any idea about what dates it may have been used ?

Good to hear from you about this propellor. Its clearing up alot of questions.

Have a great New year !!! - Jesse

[Max]

A period photo to get you thinking (loading torpedoes at sea)..

All the best

Max

www.atlantik-pirat.com

Edited January 1, 2010 by Max

[Norby]

Hello Jesse,

Happy New Year to all!

Well, I know very little (close to nothing, I'm afraid!), about torpedos but there is a similar discussiongroup in Denmark where I asked and got this reply (It's my translation into English so please bear with me!):

"It is with 99% certainty a prop from a T1T. After the 2nd World War II the Danish navy "inherited" many T1T from the German Wehrmacht. In fact so many that they up in '70ties used them before we got a Swedish built TP612 which was TP613.

T1T was a battery-powered torpedo, while the Swedish, which was further developed of the German one, was steam-driven. Highly concentrated peroxide, approx. 96% pure, distilled water and pure alcohol may cause a combustion in a closed system, thereby creating steam. This way: The engine is a star engine, it is in a lot of trickery, but one thing stands out, the steam producing part which is a small case, it is the size of 2 ½ L soft drink bottles. Entering alcohol and water, and peroxide when contaminated with water and alcohol, split it with such force that it ignite and this creates a chain reaction where the alcohol is burned off with high heat and evaporate the water. The steam is now being carried out to the engine. The excess pure oxygen also through the "exhaust" intends to torpedo, and will shut off quietly, so the torpedo does not pull a bubble trail".

But that's another story even the props may be the same?

Mvh Toke

[joetauchretter]

A period photo to get you thinking (loading torpedoes at sea)..

All the best

Max

www.atlantik-pirat.com

Hello Max ,

I have this picture in several of my u-boat books , but I always thought they were two two bladed props . I wish this was a more clear picture to see all the details . The reason I thought this to be twin 2 blade props is the blade angle of the 12 o'clock : blade " this looks to me like it is not a blade but the image of the vertical fin . I feel that this is a different shape than the others and too vertical as opposed to the other blades shown .

I have the bible on German Torpedoes " Die Torpedos der deutschen U-Boote by Rössler and I did find a picture in this book of a pre war torpedo called the G7a Whitehead-Schwanzstück ! All or most post war torpedoes show 6 blades .

Best Regards ,

Joe

[Max]

Hi Joe

Yes, it's a pity the photo isn't clearer. I have nothing concrete either way, but I thought I would post up the photo to generate a little more interest in the thread.

Cheers

Max

www.atlantik-pirat.com

[joetauchretter]

Hello ,

Please see the new topic " TORPEDOBUCH " AND LOOK AT PICTURE NUMBER 8 .If I translate the page correctly this torpedo had a 6 blade propeller ! It does look like for whatever reason some torpedoes did have the 6 blade version installed . I see these 6 blade props on ebay very often and I still doubt these are all pre 1945 made .

Best Regards ,

Joe

[Jesse]

I found these photos the other night going through "U-Boat War Patrol" by Lawrence Paterson, page 100. They show some good shots.

The book covers the patrol of U-564 during the summer of 1942. This would lead me to believe that the 6 bladed screws were in fact used mid war as opposed to late. This of course is an assumption because the individual photos are not dated. Only the time that the book records the boat's activity is dated.

Does anybody have any original KM Torpedo manuals or could perhaps point me in the right direction ? I'd like to reasearch these more. There seems to be alot of unknowns about these and I'm very curious.

Thanks Gents - Jesse

[Jesse]

Second photo in the book.

As Joe said, there were alot of 6 bladed props used after the war. These that were used during the war must have some identifing marks on them I'd think. Maybe a manual with these will show up one day?

[Natter]

I see this same type of propeller on ebay all the time and in my humble opinion these are at best post war . If you look at any picture of the standard type G7a and G7e both use two twin blade blade propeller that turn in a counter rotation.

I'm sorry, but you are wrong...

This is a genuine german WW2 G7a propeller. The G7a's used also 4-blades early on, but this was soon replaced by the standard 6-blade. Brass was used as long as the raw-materials were available, but during the war it was replaced by steel.

The RNoN used the G7a until 1999 - designated "T1 mod 1" after it's initial wireguidance-modification in the late 60's (it kept this designation until it's retirement, although the guidance-system was modified 3 times later on, the last one in 1992).

I don't seem to have the priveleges of attaching photos, but you can see the tafel of the propellors from the german Marinedienstvorschrift "G7a zeichnungen" here:

http://www.uboatarchive.net/G7a-Plate24.jpg

[Natter]

I got it from a Norweigian man

that is a member onthis site, if I remember correctly. He works with a local museum and sent me

lots of photos of complete torpedos that the museum owned. I was suposed to get some special torpedo

tools with the prop, but that never materialized. I will look in my original torpedo manuals to see

if I can find more info on this. Here are photos of the torpedo tools.

I must say I find it a little disturbing that someone are selling properties of museums... As I'm currently involved in the work of restauring a norwegian (orioginally german established) shore torpedobattery, I would really like to get in touch with this guy - we need tools for the exhibition...

Personally I have a complete set og G7a brass-propellors, a gyroscope and some kartuschen-shells.

[Natter]

When I list a reply I try and base it on information / pictures that have . I attach some period pictures that clearly show two twin blades props . You can clearly see they are WWII u-boats and Kriegsmarine sailors .

You need to distinguish between the G7a (wet-heater with "whitehead-tail") and the electric G7e torpedoes. The latter was a simpler design, as they were intended for use by submarines (less stress on the torpedo compared to a surface-launch), and they had indeed 2-blade propellers.

[Natter]

I wonder if aircraft torpedoes and S-boats used a different type of torpedo ?

Luftwaffe and kriegsmarine had little cooperation during the war (although there were some cooperation in regards of pistol-design). Besides that, no aircraft could use a standard, heavy (G7a prepared for shot: 1582kg) "G7" torpedo (ie 53cm diametre / 7m length). Luftwaffe used "lufttorpedoes" (LT), all of 45cm diametres and 5 metres lenght (designated "F5"). I'm no expert on LT's but as far as I know, most had 4-blade propellors.

[Natter]

I too have seen this picture before ! I wounder as the color is not corrext and the shape of the tail section like different to me I wonder if this is a post war torpedo or a post war modification to a WWII torpedo ? I have a East German Navy Handbook on torpedoes and the 6 bladed prop looks almost the same as this picture . One must also remember that this boat was used post war for a long time with the Norwegian Navy and the boat was heavily modified.

First: I don't think the U-995 was that heavily modified in norwegian service, but as far as I know, the germans have made their best to restore her back to WW2-standard (still some norwegian text is ivisible on gauges etc. though :-) ).

The torpedoes in the U-995 are G7a having served post-war with the bundesmarine (easy to see as they were painted blue as an anti-corrosion effort - a problem not very relevant during WW2). Other than the paint, this is a original G7a though.

The G7a in norwegian service was modified with wire-guidance (the danish navy did a very similar modification to their G7a's in post-WW2 service) - as I mentioned above, but other than incorporating a 12km wire-spool and a box with electrnics and batteries, and some modification to the gyroscope, the torpedo was completely original also in Norwegian use.

[Natter]

You are right but it's the smaller prop you see more clear than the bigger prop below, so I have taken a few photos and uploaded them to my home page:

http://www.norbyhus....e/torpedos.html

The photo below is not from our sitting room (!) but from our Danish Naval Museum - as far as I remember. I couldn't find the mail with the link, though - but i'll find it later.

The pointed teeth are very sharp as the prop probably hasn't been in use ever. The bigger to the left seems to have been mounted and has some repairs here and there on the blades/wings.

Unfortunately, I can't see your photos (I realize this is an old thread), but ai have a good theory of the reason for the modified back G7a-propeller (the largest one showing signs of wear is the front propellor of the contra-rotating set). As we scarpped a lot of the over 1200 G7a's we "inheritated" from the germans after WW2, some parts were of course kept, and propellors and gyrscopes where especially populuar items used for gifts to retired officers etc. "New/unused" propellors were in particular good as they could be polished to a very high degree of finish (as your small/back propellor). It was very common to remove the material from the hub and put a clock or barometre etc. in there for the whole set to be mounted on a wall. I'm sure your propellor was intended for such use (I can assure you: That finish took a great del of work to accomplish - I haven't even considered starting on this for the propellors I have in the basement...).

[Natter]

Do you know if it was made by Norway ? Also any idea about what dates it may have been used ?

As posted above, these are original german WW2 propellors, used by both the norwegian and danish navies after the war. Norway used the torpedo on it's submarines, MTB's and shore torpedobatteries. It was retired from the submarines in the early 80's I think, and from the MTB's around 1990. The coastal artilley (torpedobatteries) used it until 1999.

[Natter]

"It is with 99% certainty a prop from a T1T. After the 2nd World War II the Danish navy "inherited" many T1T from the German Wehrmacht. In fact so many that they up in '70ties used them before we got a Swedish built TP612 which was TP613.

T1T was a battery-powered torpedo, while the Swedish, which was further developed of the German one, was steam-driven. Highly concentrated peroxide, approx. 96% pure, distilled water and pure alcohol may cause a combustion in a closed system, thereby creating steam. This way: The engine is a star engine, it is in a lot of trickery, but one thing stands out, the steam producing part which is a small case, it is the size of 2 ½ L soft drink bottles. Entering alcohol and water, and peroxide when contaminated with water and alcohol, split it with such force that it ignite and this creates a chain reaction where the alcohol is burned off with high heat and evaporate the water. The steam is now being carried out to the engine. The excess pure oxygen also through the "exhaust" intends to torpedo, and will shut off quietly, so the torpedo does not pull a bubble trail".

But that's another story even the props may be the same?

The danish and norwegian G7a-history are quite common (we also replaced the G7a with swedish TP612 on the submarines/MTB, and then TP613 on the MTB's and finally TP613 in the coastal artilley.

The explanation taken from the danish forum is somewhat confusing though: The german naval code for the G7a was T1, so "T1T" must be a danish designation (similary the "T1 mod 1" was a norwegian post-war desigantion). We (Norway) never used the german G7e (electric torpedo, german navy desigantion T2-T3-T4 etc. depending of variant), but I know Denmark did for at least some time after the war (I belive they stopped after a few years due to a lot of problems/ losses of these torpedoes). I suspect the danish authour might have mixed up G7a and G7e in his/her description, although the part on TP613 seems accurate.

[Natter]

Does anybody have any original KM Torpedo manuals or could perhaps point me in the right direction ? I'd like to reasearch these more. There seems to be alot of unknowns about these and I'm very curious.

There are some manuals available - I have several, although I miss some...

Typically, the germans had three M.Dv.'s (M.Dv. = Marine dienstvorschrift) covering each torpedo: "Bescheribung" (covering the construction and function of the torpedo), "Zeichnungen" (tables with drawings of the torpedo and it's components) and "Bedinung" and/or "Wartung" (covering maintenance routines).

I'm in particular looking for the "zeichniungen" vorschrift for the G7e torpedoes if anyone have an idea of a copy somewhere...

[Norby]

Unfortunately, I can't see your photos (I realize this is an old thread), .......

Hi Natter,

Sorry you couldn't find my page but I moved it when I changed internet provider early in 2010. Now you can find the page here: http://www.norbyhus.dk/maritime/torpedo/

Enjoy

Toke

[Natter]

Sorry you couldn't find my page but I moved it when I changed internet provider early in 2010. Now you can find the page here: http://www.norbyhus....ritime/torpedo/

Hi

Thank you. The photo from the danish musem ("Orlogsmuseet") shows a danish post-war modified G7a ("T1T"..?). The norwegian T1 mod 1 was a very similar modification. Btw: This particular torpedo have a warhead with a Pi2 pistol, and I would like to know if the danish really used these, as I find it a little hard to belive (we used only Pi1).

Your propellor nr. 3 shows exactly the typical work being done on propellors used for gifts/ decoration in Norway as well. The aft (smallest) propellor were preffered due to the size and weight). It's hard to tell from the photos, but it seems you have 2 aftpropellors ("1" and "3") and one front ("2"). On the drawing I posted a link to above, you can see how the set is supposed to align up (look at the propellor-shaft assembly on the bottom, with the hub of the propellors at the right). I could have posted some photos/ drawings, but it seems I don't have "posting-priveleges" here :-)

[Norby]

Natter,

My e-mail adresse is toke.norby@norbyhus.dk and feel free to send me the drawings etc. which could explain what I have :-) It seems that 1 and 3 are "a pair" even the outer diameter is different No. 1: 44 cm and 12.5 cm for the axle and for No. 3: 46 cm and 11 for the axle. No 2 is totally different from the two others. 1 and 3 are conical and 1 "fits" to 3.

Mvh

Toke

[Natter]

It seems that 1 and 3 are "a pair" even the outer diameter is different No. 1: 44 cm and 12.5 cm for the axle and for No. 3: 46 cm and 11 for the axle. No 2 is totally different from the two others. 1 and 3 are conical and 1 "fits" to 3.

Those measurements doesn't fit exactly with mine, but I guess it's a matter og how/where you measure. Anyway: I have sent you some photos and drawings, which I hope may be of some help to you.

[Natter]

Please see the new topic " TORPEDOBUCH " AND LOOK AT PICTURE NUMBER 8.

Hmm... I overlooked this post yesterday. I have searched for "torpedobuch" in here, but I can't find the topic. Has it been deleted??