And finally, one more observation and then I'll stop. I posted earlier about using diesel exhaust gasses to pump down the main ballast tanks while running on the surface ... saving your air banks. Well, in the ventilation diagram above, I see a separate valve that routes diesel exhaust in 3 different directions ... shown internally inside the pressure hull! Very unlikely! I submit that this 3-way valve may actually route diesel exhaust gasses to the main ballast tanks for compensating for MBT air leakages while on the surface dieseling. Very effective use for the exhaust.

...there were 3 ways to clean the 3 ballast tanks:

1. air from the pressure tanks
2. diesel exhaust
3. e-motor driven diesel engine used as compressor

And here the time needed to dump the 3 different ballast tanks
1. ballast tank 1 = 22 sec. 2 = 25 sec. 3 = 28 sec.
2. ballast tank 1 = 38 sec. 2 = 60 sec. 3 = 113 sec.


Michael

That last option for blowing down the MBTs ... the electric motor driving the diesel as an air compressor ... might just be the key to that "D AbluftMast" question earlier. That might be why the aftermost vertical tube appears to have two titles. One might be with the diesel engine running on fuel and pulling in good air through the main induction and exhaust flowing out that aft pipe. The other might be the Propulsion motor powering the diesel as a pump and exhausting the bad air through the same pipe. Fascinating boat, this XXIII!

Part # B14 is the exhaust outlet and Bronco would have you cement it to one of the tower halves before cementing those two halves together and joining the tower to the hull. This seemed like asking for trouble so once again I deviated from the instructions and cemented it to the hull instead.



I taped the tower into position first to help align B14 before applying the cement. I also painted the area on top of the hull that will be under the duck-board decking flat black.



I wanted to provide some shadow contrast under the decking once it's applied. I couldn't decide whether I wanted to use the decking or not. It seems a lot of boats had it removed, for streamlining I guess. In the end I decided it just looked more interesting with the decking and the life-line mounted. Al

Well I managed to get some painting done between thunderstorms. I used Testors' rattlecans, Gunship Gray for the upper hull, and Panzer Gray for the lower.













It's really starting to come together and actually look like a submarine. Al

Cool Will we see some RN chaps on Board? lol.

Cheers

Al

Gotta admit, that possibility had crossed my mind. Al

Painted the inside of the Tower and the bridge area, also the inside of the navigation light housings. The two halves of the tower aren't cemented together yet.







The outside of the tower hasn't received a coat of paint yet, just some over-spray. I have to mask the inside of some of the openings to prevent paint from going where I don't want it when I do join the two halves and paint the complete tower. Al

Hi Al,

Nice start on the paint job, what colour are you using?

Alan

Nice paintjob Al!
...and here's some progress from my dockyard - but again only bits and pieces.
I found a the pic in Rösslers booklet: FuMB 26 "Tunis", a submarine radar search receiver for the S-Band and X-Band signals, of 1944/45.
In the begining only small parts:



Assembled:



The later position, instead of the flag pole:



Finally with a guard bracket:



I hope you like this gimmick...


Michael

Michael, That looks like something Rube Goldberg might have come up with, but I do like it. Very nice scratch-building of an interesting piece of equipment. Al

Thanks Alan, I'm using Gunship Gray for the upper hull and the tower, and Panzer Gray for the lower hull, below the waterline. Both are Testors, from rattle-cans. Al

Ahoy Al,

That is turning out just amazing.

I am eager to see her with a crew in the tower!

Keep up the great work,
Cheers,
Joe

Al,

Very tidy and understated paint job on the hull, excellent.

Michael.

Great bit of scratchbuilding on the radar.

impressive work guys.

Si

Great to see some colour going on. She is looking great.....Cheers mark

Boys ... my congratulations are doing an excellent work!!!

Im extracting notes for the mine!!

Regards

Question: Starboard side, just above the flood ports for the amidships main ballast tank ... there's a round indentation just forward of the small hull penetration in the hull. I'm taking that to be the ballast tank vent. Page 57 in the book shows a slotted grate in that indentation ... so I'm fairly sure that's the air vent. Anybody got any plans to render that grating ... and, if so, how?

Also, that hull penn aft of it seems too small for scale if you compare it to the photo on page 57.

Yet another observation regarding the bridge lockers: With a test depth of 590 feet at the keel, this boat could withstand about 255 psig sea pressure ... or about 220 psig in the bridge area. My comment regards the apparent construction of those lockers: do you guys think those were water/pressure tight? My guess is that they were convenience lockers for the bridge crew ... but that when submerged, bridge items such as the UZO, binoculars, very pistol, semaphore lamp, or oilskins would be hauled belowdecks rather than kept in those lockers. Otherwise, they would have to be built like a gun safe to withstand sea pressure. There IS a possibility that they contained pressure-proof storage cylinders inside them ... I've considered that possibility as well. Even so, the lockers themselves were probably not waterproof.

The point I'm making is that these lockers in all likelihood would have free flood holes top and bottom to allow the air inside to rapidly escape and prevent them being crushed on a crash dive.

Anybody got any thoughts?

Beautiful job on the hull, by the way!

I'm no engineer or any kind of submarine expert. The boxes just above the lockers in question are the housings for the navigation lights. Wouldn't they be exposed to the same pressure as the lockers? I don't think they were built like a safe. Maybe there is some kind of pressure equalizing system, or holes, but I can only go by what little references that I have available and use them to get as close as I can to the real thing. Al

The light housings would need to be pressure-proof or else there'd be all kinds of algae inside the windows, so I think they were. The main difference between the lockers and the nav light housings are the hinged doors which would require seals and dogs to clamp them down tight ... and some kind of long lever or a wheel to draw the dogs down, just like a hatch or watertight door.

See how the liferaft compartment's sealed? No door knob on that baby; it's a proper watertight door.

I wish we had more references on this boat because a lot of things just don't click for me.

Another point is the two ventilation pipes in the sail right next to each other. You never put exhaust air or diesel exhaust right next to an induction pipe or you end up drawing that exhaust right back into the induction. Maybe they didn't use the two simultaneously; maybe air was drawn in through the main hatch in the sail whenever they used the exhaust pipe in the sail ... and maybe they only used the induction pipe when they were using the port side exhaust silencer.

Figuring this boat out is going to be a challange. I hope they raise 2359 and I live long enough to get a look at her!

Some more work on the Tower. I decided to consign the kit supplied ladder rungs to the scrap box and replace them with new ones made from brass rod. First, I drilled the appropriately sized holes in the front of the tower.



The rungs were made using my Hold & Fold and then super-glued into position. One of them is just inserted (not glued) into place to make it easier when I do the ID stripe that goes around the tower.





I also added the storage compartment hatch. You may have noticed that some putty work was needed after cementing the tower halves together. There were no gaps, just a minor step at the seam in a few places. There should be a 'Bull's Horn' shaped cleat on the aft end of the tower's turtleback. Bronco molded the football shaped base but forgot the 'horns'. An easy fix using some more brass rod.



I've had to spend a lot of time and effort on the tower, but, (IMHO) it's been well worth the effort. Though I am surprised, and a bit disappointed, that Bronco made it necessary in the first place. Al

...small steps for mankind, but giant steps for Al
Well done! Don't forget the that little bars guarding the holes:





Michael

Handholds, I believe.

Maybe - or guards not to step into that holes...

A small update, I thought the kit supplied handrails for the tower were a little flimsy looking. So, I made my own.



Michael, the openings in that photo appear to be larger than the ones molded into the turtleback, I would need to enlarge the holes a bit to add the bars across them. Since there seems to be a lot of variation between boats mine just won't have them. I do think William is right about them being handholds seeing as there is nothing else back there to grab on to. I can't think of a reason anyone would be climbing up there. Al