@Al & Darren, old myself is wondering one thing, reading the magnet issue and the open torpedoes door open...

I can't help asking myself if you take the time to inform the company/builder of this model? Inform of this issue and the other one about the bulkheads distorting etc etc?

Just a thought I had while starting to read this thread.

Marc

ps: I'm starting to feel like helping Jim and his problem with "needing help building and blogging about a model given by a company" and I don't know the "do's or don't" in this subject.

One thing. The XXI and the XXIII had steel propellers not bronze. http://www.uboatarchive.net/DesignStudiesTypeXXI-S44.htm




So I guess bronze could work depending on which boat you are building and when she was fitted out.

Still a great build! I had lost track of it for a few months. I have a lot to catch up on.

- Leelan


http://put.url.here

My guess is that being forced to use steel for propeller material is the primary reason for all of those zinc anodes adorning the hull of the XXIII. It's starting to make a little sense; some of the hulls had none and some had just a lateral line of zincs ... and some sported them from amidships aft to shaft alley and then returning back up to the waterline.

The galvanic corrosion on those steel screws must have been terrible and they just kept adding zincs that were cast as semi-tubes in cross-section to increase surface area without adding undue drag to it. Stainless steel would have been just as scarce, I think, so the screw would have been high-grade structural steel. No paint or coating would last long whirring through salt water ...

... but perhaps they might have been able to plate the prop with copper and then temper that with chemicals. From one of the yacht forums:

"From the time that they are immersed into a marine environment, bronze propellers are prone to attack by marine organisms, such as barnacles, coral and algae, which attach themselves to the bronze metallic surface, creating lumps on the propeller, which adversely affect its balance and cause impedance and vibration of the propeller and its boat in the water. Anti-fouling paints are either too toxic for the marine environment or lack smoothness on the surface. These problems have been overcome by polishing the propeller to prepare it for electroplating, cleansing to remove dirt and grease, electroplating with copper, followed by spraying with a standard solution (5%) of sodium hypochlorite and sodium chloride and allowing sufficient time for a reaction of the hypochlorite solution with the copper to form a firmly adhering conversion coating of basic cupric chloride. The coating is blue-green in color."

http://www.cruisersforum.com/forums/f114/copper-plating-propellers-45927.html

All of the photos of XXIII screws appear to be a dark color ... so my bet's on copper-plated steel props with a sodium hypochlorite/sodium chloride treatment or similar coating ... and then tons of zincs on the after end of the boat.

My plan for my boat will be to treat the brass screw with cold-bluing solution for firearms. That will nearly blacken the brass with just a tinge of blue to it ... and then a light polishing to slick it up a bit.

I can't help asking myself if you take the time to inform the company/builder of this model? Inform of this issue and the other one about the bulkheads distorting etc etc?[quoted text]

Hello Marc, no, I haven't spoken to Bronco about this kit. The bulkheads were not distorted. The problem was that though there were internal bulkheads molded into the two larger front halves of the hull, there weren't any in the smaller rear halves. Because of the way the pieces were packed the edge of one rear half slipped inside the edge of the other. This resulted in one rear half being slightly distorted, but it was an easy fix. For such large moldings, the fit of the hull halves was quite good and required a very little putty work. The kit goes together well, IMHO where it falls short is in the amount of missing detail, particularly in the bridge area. Al

Thank you for your answer. [OFF-TOPIC]I had a problem once with a Revel plane, I know it's off-topic, but I did inform them, they phoned me back and in the end, I received a brand new model with the fuselage/wing joint fixed. I could put my little finger in the joint. And they had no idea how this could pass the quality dept, since they checked 2-3 models and they all had the same issue.

Take care,

Marc

==================================================

What difference would it make in having a bronze or a steel screw on a sub? My guess is it's not more speed. Could it be the time it takes to rust?

... some progress on the german Shipyard. The hull got some grey - XF-24. I think the 2 colours are a good match:






Michael

You painted the zincs!

Painted zincs do not corrode well, Michael! Their function is to corrode and they are left unpainted!

Yes, I've painted the zincs! But only in the first step of painting that beast. It's better to airbrush the large areas first grey and to do the detailing of the zincs later; they will get their metallic look asap.
Today it was time to start some weathering with a warm grey filter:





Using only two shades of grey and the result will be too uniform. But I think this filter was a good choice and I'm pleased with the effect.

But the very first work today was to alter the stand: some styreen plates added and the problem of clawing the paint was solved:




Michael

Ah, I see. You'll use, perhaps, a metalizer for them? Remember that they corrode and produce a spongy, whitish powder over the surface much like that formed on a battery post in a car ... shiny in spots and powdery in others.

Your model may very well be the first to show the correct depiction of submarine zincs, you know. I've never seen that rendered in any other models.

Nice job on the hull, by the way!

See http://rogercortesi.com/portf/uec/
for a depiction of U.S. Navy zinc anodes which are welded to the hull. No paint.

Before detailing the anodes with paint, here's a pic of the detailing already done there and now covered under a layer of grey: the Archer rivets in comparison with the real rivets:





Michael

Looking good Michael, she's coming along nicely. Al

Today the first pigments to get some rust to the hull:



I'm nearly pleased, but the track of the pigmentfixer... Will check it tomorrow at daylight.




Michael

Now some paint for the anodes: XF-56 Metallic Grey and a little bit of pigment (white ashes) to the spaces between the zincs:

   

   

...not so bad in some distance:

   


Michael

Looking great Michael, the rut streaking is very convincing.

Si

The zincs ... superb! It was always interesting to note that some zincs corroded more than others according to where they were. Probably had to do with what machinery was just behind the pressure hull at that point. The hull was never used as a ground, by the way.

The rusty trails should stop somewhere above the waterline, though ... where they would be diluted in the wash of the lapping waves. I assume you will wash below the waterline with simulated sea growth or barnacles and cover them up?

We could always tell which boats were returning from a northern run because their hulls below the waterline had no green algae growth swaying in the watery currents ... just black paint. Warm water patrols would quickly upholster the boats with a yellowish-green beard as far down as the eye could see. Any growth above the waterline died in a matter of an hour or so once surfaced.

Beautiful paint work, Michael ... masterfully done.

thx for your comments!
I will show my beast while docked. So it will be possible for some rusty streaks running down below the waterline. The tower interior and the silencer (hot metal/salty water) are the 'spring' of the rust to be washed out by rain e. g.


Michael

In the moment I'm trying to build a part of a floating dock as a display for my beast using styrodur, a kind of styrofoam. And this is the bassic design:



But all startet "creating" the pawls. As no H-profile was available I bought some T-profile and a lot of polystyrene sheets and balsa:



The first result:


Some PS-chevrons added:



Here's the whole outcome: 20 pawls


...and U-2336 on the styrofoam parts for a 1st impression:



Michael

That looks great, Michael. It will be a very impressive display when finished. Will you be adding figures? Al

Hi Al,
figures? At least a worker changing the anodes. And some crew members examining their dry boat.


Michael

Looks like a great beginning for a diorama, Michael. A few tips for you: whenever in drydock, subs nearly always lower the anchor down to the dock's deck for chipping and painting along with all of the chain as well. It's the only opportunity to do it. The hull is scraped and primed in swaths ... so there are patches of gnarly barnacled hull, patches of scraped hull, patches of primer, and patches of new paint. Flood vents grates are removed and men enter the ballast tanks from the bottom for sand blasting and painting. If the diesel will be worked on, a hose is connected to the sea cocks to supply cooling water to it. The periscope is usually hoisted clear of the boat to replace the scope shear's seals. That battery hatch would probably be opened too and a plywood chute inserted so borderline battery cells can be replaced. Large puddles of water everywhere underneath; it's never dry in the drydock! Hull access plates everywhere come off; scaffolding goes up around the screw and that torpedo loading skiff might be in place, too.

This could be a hulluva job!

?? Now that I think of it, I don't recall seeing an anchor on the XXIII! That may be related to the way she loads her torpedo tubes. Normally, the anchor windlass doubles as the power source for the forward capstan ... which is the power source for lowering torpedoes down the skid into the torpedo room. This boat, however, is a muzzle-loader, so no capstan ... and no anchor windlass! Weight and space savings.

...again some progress with my floating dock:

At first an overlay with 1.5mm styrene plates to cover the bubbles



And some Evergreen tubes (10x10mm) with a few holes drilled



For what? As stakes to support the docks front



Followed by stanchions (Robbe, 25mm, 3 eyelets) and florist wire (0,9mm):





By the way: my dock is only staffage, a nice background for my beast; therefore I beg for mercy



...will be continued with some detailing of the "wall" and the upper part


Michael

Hi Michael,

This will; make for an excellent display.

Al

Today only small potatoes: handrails with stanchions added to lower and upper stairway




Michael