Where is diesel exhaust port on Type IXC/40 (U-190) ?

[GlennCauley]

Here is a comparison of the stern hulls of Type IXC/40  vs.  Type IXC.




The IXC has a round diesel exhaust outlet; the IXC/40 does not.


During below-surface operation with the schnorkel raised, the diesel exhaust would come out through the schnorkel.


Where is the diesel exhaust port on the Type IXC/40?
It would need one for surface operation when the schnorkel is retracted.

[GlennCauley]

Here is a pic of U-190, showing 6 small inline louvers at the back end of the main flooding channels.
Are these the diesel exhaust outlet?

[GlennCauley]

Unless told otherwise, I will be making the following mod to U-190 to create what I believe are louvers over the diesel exhaust outlet on both sides of the hull.
These look like a series of 6 louvers the height of the main flooding channels.   It looks like they end just short of the back end of the torpedo rolling rails atop the main deck.

Have started by blocking off the rearmost flooding channel with a block of strip styrene, will fill in & smooth, then drill holes & add louvers.
If anyone has ideas on how to create those louvers, please advise.

[Capt Kremin]

Hi Glenn,


don't fill the holes the original vent holes are behind the louvers/ducts, I will find a picture or 2 of these vents on the U 534 over the weekend, as to why the forward and aft vents had ducts, frankly I don't know.


Yes, you are right with the exhaust, there were some boats that had no silencers and exhausted below the water level, U 190 was not one of those, this is apparent by the exhaust fairings in the deck, those boats did not exhaust through the schorkel.


Regards
Jon

[GlennCauley]

Hi Jon,

Yes, pics please!     
Unfortunately, I don't know what you mean by "exhaust fairings in the deck" though, sorry.

Drat, I'll have to remove the plug I cemented into place in that last flood channel.

[dougie47]

Hi gents,

Jon, I think we discussed the big hole in U 858 but can't recall for sure what the conclusions were. Currently I'm thinking that the big hole was possibly for the diesel exhaust. Would that be right? The hole I am talking about is the great big one (you can't miss it) just below the waterline in this shot of U 858 in 1947 -



I'm thinking there would be several styles on IXCs and IXC/40s, with boats being upgraded to have different styles as time went by.

Style 1 - on pre war U 38 and early war U 124 - round hole above; (with a gap present in the main vents)
Style 2 - the normal one used on most boats in the war - rectangular hole high up, with two small squares low down; (with a gap present in the main vents). Note that U 530 and U 534 appeared to retain this style at the end of the war even though they both had snorts.
Style 3 - as style 2 but with a shroud over the rectangular hole; (with a gap present in the main vents) - U 505 has this one at the moment
Style 4 - In the final years some boats with the snort had the giant hole seen above on U 858 (I'm assuming this is an exhaust outlet but I may be wrong as it does seem unnecessarily large). Note that the main vents are an unbroken line, which is the only clue to this style in evidence in photos above the waterline. U 190 had the unbroken vents so it is quite possible that U 190 had this style with the giant hole.

Note: The IXD U 873 also had style 4 but with a shroud over the top.

The final diesel exhaust for VIICs was brought beneath the waterline in a very similar position to style 4 so I am thinking that this style was implemented to some (but not all) VIICs and IXCs at the end of the war.

Above is a quick study so I imagine there were others styles too.

As for those extra 6 ducts at the rear of the main vents (and the similar ones in the forward hull), could they be to improve diving times?

Cheers,

Dougie
 

[GlennCauley]

There are a few pics here that definitely show that there are no diesel exhaust outlets above the waterline:

http://www.forposterityssake.ca/GALLERIES/U-190.htm

But there are no pics here of louvers at the FRONT of the main flooding channels on this boat.

[Capt Kremin]

Hi Glenn, Dougie et al,


First let me say damn, the picture that I was thinking of must have been out of focus or something as I have deleted it.
Attached Hull-19 is the forward ducts which appear to have been cut away, if you look at the middle hole it can be seen that it has rounded corners, the same as the original vents in that location.
Hull-42 shows the aft it is possible to visualize the original vents behind the ducts, trust me they are there, (another photo to put on my list for my next trip), note that the ducts are formed from individual sheets, probably formed over a former judging by the  have curved edges.



Silencer fairings, seen either side of the center line in Image2, note this is U889 which has 8 holes per section, there are various patterns of holes, the fact that the U190 has these would imply that the silencers were still fitted.


Dougie, we came to the conclusion that the hole was a sub surface exhaust which may have had a fairing fitted to cover some of the hole.
In a report about sub surface exhausted fitted to U boats I found to said that the exhaust was used during surface and schnorkel operations, also there were no silencers fitted, presumably this must have something to do with back pressure as the underwater noise would have made any boat much more prone to being found by ASDIC at a large distance, possibly before a schnorkeling boat could detect a surface vessel.
I found an RCN report on the U190, but it is not available online, only from Kew and it seems to concentrate on the sonar and radar fit on the U190 and U889, so may not be much use, if it was a full technical report it would certainly contain information of a sub surface exhaust if fitted. The report was sent to both the Admiralty and the USN, maybe it is available from a US records site.


Regards
Jon

[Capt Kremin]

Hi Glenn,


Also the schnorkel that is fitted to U190 has an exhaust port, which it would not need if it had a sub surface exhaust, I would put money on the vent you arrowed on the model to be the exhaust, see attached. It may be more than coincidence that there is steam or white diesel fumes are exhausting from that area.


Regards
Jon

[GlennCauley]

I'm such an idiot.
The kit includes 2x of the 6 inline louvers, to cover the rearmost 2 flood channels.   They are shown in the 2nd last page of the instruction book, and I missed them.  Sorry. 

For the 3 front louvers (that your pic shows ½ cut away), it looks like they are molded onto the hull, up high near the deck and above the forward dive planes.  They are molded as trapezoidal forms, not cut open.

Still unsure about the diesel exhausts, though.  I am not convinced that the 1 arrowed channel is an exhaust.  The fumes do not seem to be coming from that, seem to be coming from much higher above (deck?).   Also it seems to me that on IXC and VIIC that the diesel exhausts were not directly in line with the flood channels, they were above or below.   (This is just observation on my part, though.)

The 2 long bulges on the back of the deck... with the small holes on their centerlines... I thought they were something else other than exhaust covers?

(Please excuse my ignorance on these boats... I am not used to them yet.)

[NZSnowman]

Style 4 - In the final years some boats with the snort had the giant hole seen above on U 858 (I'm assuming this is an exhaust outlet but I may be wrong as it does seem unnecessarily large).

When I was researching the final style of exhaust outlet on the Type VIIC’s. I draw up a few cross sections of the pressure hull and casting around the exhaust outlet. I noted to get the exhaust outlet down that low, there is very little room between pressure hull and casting, hence, the German’s increase the size of the outlet to get that volume of exhaust gas outside. Perhaps they had to do the same thing with style 4, as I imagine there very little room between pressure hull and casting.

[Capt Kremin]

Hi Glenn,


Most boats do have exhaust ports higher, but there were various experiments which I think the U 190 was one.I think the picture I posted is showing steam from a hot port exhaust pipe, like I've said before, I could be wrong.
The fairings with the small vent holes are just silencer covers, the deck is lower than the top of the silencers which goes with Simons point about the shape of the exhaust port. It' eaqually posible that the designer thought it was aesthetically pleasing to have the exhaust to match the shape of the drain holes
I looked through the instruction manual when my U190 arrived and I missed the louvers.


Regards
Jon

[GlennCauley]

I looked through the instruction manual when my U190 arrived and I missed the louvers.

LOL step 51, parts #200 & 201.   D'oh!
Well, at least I know how to make them from scratch if push comes to shove!   

[NZSnowman]

I think the picture I posted is showing steam from a hot port exhaust pipe, like I've said before, I could be wrong.

On the Type VIIC’ the exhaust piping outside the pressure hull has a water jacket around it to stop any steam happening. The same system is on the Type IX. If memory serves me correctly, I believe they use hot steam to heat the boat while at harbour and I believe the inlet was in the rear of the boat through the engine room.

A few things suggest this is hot steam to me, i.e. at harbour, the hoses, and the location of the steam.

[NZSnowman]

Style 4 - In the final years some boats with the snort had the giant hole seen above on U 858 (I'm assuming this is an exhaust outlet but I may be wrong as it does seem unnecessarily large).

When I was researching the final style of exhaust outlet on the Type VIIC’s. I draw up a few cross sections of the pressure hull and casting around the exhaust outlet. I noted to get the exhaust outlet down that low, there is very little room between pressure hull and casting, hence, the German’s increase the size of the outlet to get that volume of exhaust gas outside. Perhaps they had to do the same thing with style 4, as I imagine there very little room between pressure hull and casting.

I think this statement is wrong. There looks like there is heaps of room to put a pipe vertical down between the casing and the pressure hull in this area.
 
Perhaps it was something to do with the seaward pressure on the exhaust gases?

[Capt Kremin]

Hi Simon et al,


I hadn't considered a water jacket around the exhaust, makes sense on several levels, on the VIIs does the jacket finish at th end of the silencer or go all the way to the end of the exhaust?


There is definitely an issue with the water pressure on the exhaust as I said previously on the sub surface exhausts on the IXs (experimental) and the XXIs (production) they did away with the silencers all together. I assume that the exhaust would have to have a pressure differential valve in it otherwise the engines would flood, (no valve) or the manifold gaskets would blow, (manual valve). I am not saying that there wasn't a manual valve, but there would have been an automatic pressure differential valve as well.


regards
Jon

[NZSnowman]

I hadn't considered a water jacket around the exhaust, makes sense on several levels, on the VIIs does the jacket finish at th end of the silencer or go all the way to the end of the exhaust?

Finish at start of the silencer.

...but there would have been an automatic pressure differential valve as well.

I don't believe there is a automatic valve, but Tore will know.

[Capt Kremin]

Hi Simon,


I was thinking about the sub surface exhaust for the differential valve which would constantly under water pressure, not the normal systems or on U190.


Regards
Jon