? "Early" magnetic compass mount

[SG]

Hi, I've been doing some research on U-48 and after checking pics showing the magnetic compass mount fitted to the aft surface of the attack periscope base of U-47, 48 and 51, the idea that most of the early type VIIB boats (the early Germania Werft ones i mean) were equipped with an "early type" mount has been taking grip on my brain.
I mean a mount which was different from the curved,"hook"-shaped mount we're used to see in most of the pics of the VIICs and VIIBs from other batches and shipyards (such as U73-74 and 86) and that u can see in the pics below
(U-373)

(U-94)

 
A mount, the "early type" one, which appears to be semi-circular or circular in shape and flat.
VIIB's which might have been sporting the "early type" mount:
(U-47)




U-48

U-51

 
I found a pic of a type IX which could be sporting this kind of mount (U-106, below),

but I need confirmation from you Gentlemen in the forum that my conjectures are right and so that:
a) what i call the "early type mount" really existed
b) that earlier batches of  VIIB's were equipped with it
If my hypotesis is right and you have clearer pictures showing the flat "early mount" in details, please don't hesitate to post them in ur reply or as a PP to me!! I would be really grateful for that .
Cheers
SG
 

[Mr. Bill]

Very good question.  I looked everywhere for this information on U-45 at the time of commissioning and could not find any conclusive evidence.  It appears that other early VIIB boats had a compass mount installed on the periscope housing at some point, but it is unclear if they were commissioned that way.  I don't believe that U-45 had one at commissioning, but I am not 100% certain.  Being the prototype VIIB, U-45 had some unique features not seen in other early VIIB's and may not be a good example.

Cheers,

Bill

[SG]

Hi Bill, First of all thanks for the reply. I've been reading all of your threads about early VIIBs features and U-45 and consider them as fundamentals for any VIIB modelling. You've been doing a hell of fine research, congrats! After doing a lot of photographic research myself i came to the conclusion that pre-war VIIB's weren't initially fitted w the attack periscope compass. By mid-1940, the time am trying setting my U-48 in, most of the boats from that famous batch U45-U55 from Germania Werft had been equipped w it and the compass mount, barely visible in most of the pictures, seems not to be of the curved type (which was sported by the boats from Flenderwerft and Bremer Vulkan though). I agree w you that U45 could be an exception, and being the first boat of the series and having had such a short career, just didn't make it in time to get the changes the other boats would undergo by 1940 or had had some improvements done which can't be confirmed due to lack of photographic evidence (her second and last patrol started on Oct 1939). Anyways, as always this is just my humble guess. I need evidence i cant easily reach to have my suppositions confirmed. I am confident that most of the experts in the forum will be able to make light on the subject...and probably to show details of the phantom "early mount".


Most of the turret deck features of my tiny U-48, if i will ever be able to start working on it again, will be based on your outstanding U45, which i hope to see completed soon. I'll probably ask you additional infos on VIIB details in the future, if you agree Bill


Thanks again
on standby for more infos

[Mr. Bill]

I will be pleased to help in anyway I can and I am sure that others here will do the same.  I agree with you about the pre-war VIIB's not having the compass on the periscope housing - it would be helpful to have this confirmed.

Cheers,

Bill

[SG]

Ha! found nothing among those boats?...change type of boat!
And so, searching among IX's..
 
(U-130)

[dougie47]

Hello gents,

Excellent discussion, well done on noticing this.

Firstly I think you are right that there was an "early mount" fitted to the early Germaniawerft VIIBs. It was clearly different to the mount on U 99, U 94 etc. in the manner that you described.

What I think happened was this. The early VIIBs from Germaniawerft all had the 20mms originally on the aft deck. They also had an early style of attack periscope base with a vertical ridge along the rear of the base (see page 71 of Wolf Pack). They also had a magnetic compass mount that SG calls the "early mount".

When the decision was taken to move the 20mm to the tower, the existing boats all had the 20mm moved to the tower but their attack periscope base and "early mount" remained the same.

However, the new build VIIBs (U 99, U 100 etc) and VIICs (U 551, U 94 etc) were all launched with the 20mm on the tower; they were all fitted with a new type of attack periscope base (see page 88 of Wolf Pack) that I called the standard base. This new base was slightly thinner and allowed more movement by crew moving around the tower. This new design of base came along with a new style of magnetic compass mount (SG called this the curved,"hook"-shaped mount) - these bars were thicker and presumably made for a more solid mount.

So I'd say you are completely right about the early mount, SG.

I can't be certain but I think you are also right on the question of whether the earliest VIIBs had the magnetic compass mount or not. This is what I can see -

U 46 - unidentified pre-war - did have the magnetic compass mount
U 48 - 22 April 1939 - commissioning - did have the magnetic compass mount (at least I think so - it did have the bendy bars at the rear of the attack periscope)
U 49 - 12 August 1939 - did have the magnetic compass mount
U 51 - 6 August 1938 - commissioning - can't tell for sure but does NOT look to have the magnetic compass mount (the bendy bars are not there at the rear of the attack periscope so this hints at no magnetic compass mount)

I would guess that the early magnetic compass mount was not fitted on the very earliest VIIBs such as U 45 and U 51 when they were commissioned. But they were fitted on VIIBs at some stage prior to April 1939. Can anybody provide any more info?

SG - U 48 in mid-40 had the early magnetic compass mount for sure.

Hope this helps,

Dougie

[SG]

Dougie, I was hoping you would turn up! I've been reading and reading your excellent study on U-47, actually the first pic of U-47 in this thread comes right from that study!    This discussion wouldnt have been complete without your precious effort.
Outstanding analysis, as usual.
Do you think the "early" compass mount sported by the VIIs was the same as the one equipping the IXs shown in the two pictures posted above? It could reasonably be to me (though in that 1st U-47 picture it looks like there's some lateral fixing arm to the main ring mount), a standard periscope base compass mount for subs in 1938-39 maybe?
 
Two more pics. Details, details.. if this is the guy, he's got no secrets anymore!

U-38, first war patrol, Aug-Sept 1939

U-38, 1939

 

 
 

[dougie47]

Hi SG,

Thanks for your words, glad the article can be of use.

I think the "early" compass mount looks very similar for the earliest Type VIIs and IXs but there may have been small differences.

Here are three photos of U 47 -


Above: U 47 8th October 1939


Above: U 47 6th July 1940


Above: U 47 24th October 1939

The green arrows points to the round ring surrounding the bottom of the compass mount. A similar ring can clearly be seen on the U 38 photos. The question is whether this ring is exactly the same on U 38 and U 47. The U 38 ring clearly has a rim around the top. This rim appears to be just visible on the 8th October 1939 image of U 47 but for some reason it does not look to be there on the 24th October 1939 image. Other that the rim it looks pretty similar, if not the same, on U 38 as on U 47.

You have already identified the main difference between U 38 and U 47 - the fixing arm - which I've pointed to with the blue arrows. It is clearly there in the U 47 photos and was on U 46 and U 48 too. It is clearly absent from U 38.

The red arrow points to where the black rubber hose thing enters the attack persiope base on U 47.

Type IIs did have the same type of magentic compass mount but the means of securing it to the tower was quite different due to alternate location of the mount(s).

While we are on the subject, it was normal for the compass mount to be roughly level with the top of the attack perisope base. However, this was not the case with U 94 and U 99 - both these boats had the compass mount raised to a higher level above the top of the attack persicope base. U 94 and U 99 were among the first to receive the new type of mount so perhaps the new design was not finalised by the time it was implemented upon U 94 and U 99. Note that U 95 had the mount on the same level as the periscope base so there cannot have been many boats with this "higher" mount.

Hope this helps.

Cheers,

Dougie

[SG]

Excellent, this is getting really awesome! A few more questions and thoughts, Dougie:
 
-the fixing arm you pointed to w the blue arrows looks like "horse-shoe" shaped to me with the convexity pointing upwards (so a single two-pronged piece rather than two separate arms linking with the ring mount), what do you think?

-And do you know what's that mess of unimaginable stuff attached to the periscope base, just below the free end of the (?horseshoe/)fixing arm, from which another thin arm connects to the hatch holder? (a propos is the black image projecting itself on the main hatch the shadow of the hatch fixing arm? it seems so)
 
- Do you have pictures of U-48 periscope base showing both the compass mount and the hatch fixing arm? now something a little off-topic: did U-48 have the mobile voice pipe just like U47 had?  am sorry but U-48 turret deck still hides a lot of secrets from me! 
 
- About the compass mount level: I had always thought the "hook-shaped mount" had some degree of mobility allowing the compass to be set to different heights thus being more operator-friendly. For example in that picture of U-94 the first man from the left, the shortest of the 3 SAs on the turret deck i mean, would have found it quite difficult to look at the compass, unless if leaning from a pedestal.. quite an uncomfortable thing.
Anyways i must reconsider and agree w you that the mount on U-94 (and most probably the one on U-99 too) could be a fixed one. it looks like there's a weld where the "hook" links w the plate connected to the periscope base.
 
Incredible pictures and an outstanding contribution. Details (whose existence i would have never imagined of) revealed!
A thousand T H A N K S !
 

[dougie47]

Hi SG,

Interesting discussion this, but its getting a bit more difficult now!

I'll address each of your points in order -

1 - Yes, it looks like it is one-pieced and horse-shoe shaped. I think the 6th July image shows convexity pointed upwards, possibly.

2 - Yes, I see the thin arm which looks like it goes to the hatch. It could be a latch because there must be a hatch latch somewhere. If this is indeed a latch then it is thinner to the hatch which would be found on VIICs later on.

3 - I'll have a look for photos of U 48 and get back to you on that. I'm pretty sure U 48 had the mobile voicepipe (it would be extremely surprising if it didn't) but I don't have a clear photo giving positive identification.

4 - I think you are correct about the mobility of the compass providing different height levels, this makes perfect sense.

Cheers,

Dougie

[dougie47]

Hi SG,

Here are photos of U 48 you might like -


Above: U 48 January 1940, Kiel Canal



Above: U 48, note air trunks are in place.

Cheers,

Dougie

[SG]

These are G R E A T pics, Dougie !!!
thanks a lot!!

[SG]

A giant "d'oh" for me! the compass mount of U-47 shown in a beautiful picture was here: http://www.u47.org/english/u47_pho.asp?page=18 (pic X02)
D'oh!!!