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Topic review - Calling all USS Iowa BB-61 class fans
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  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
One of the weirdest kinks in the plating is about 10' below the main deck right at the front of the 60 lb splinter plating at the ends of the citadel.
Post Posted: Mon Jan 27, 2020 8:35 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
BJS wrote:
Quote:
In all my looking at the plans, I have not been able to figure out the mindset at work on the hull. OK, they did not want to weld everything. But why does a single seam have multiple joints and transitions and even reversals of overlaps? The N-O seam, starts out butt welded, shifts to riveted N over O, flips to riveted O over N, then transitions to a rabbet joint, the width of the rabbet changes twice, then it switches to O over N riveted, then N goes on top, and finally at the stern, they are but welded.

I can't answer that but give a possible similar type of planking technique used on the wooden hull warships of the 18th/19th century, etc. - when viewing the hull planking laid out by a draftsman all in a flat plane, these planking strakes look like a very weird pattern of parallel boards in various curves and alignments. They do so to conform to the shape of the inner framework of the hull so that the maximum amount of each board comes in contact with it's associated frame(s) and then trenneled with wooden dowels to hold in place. It's quite possible that the over/under lapping of the N-O plating on the IOWA class hull is done to accommodate that same idea. I often wondered when looking at NEW JERSEY's hull why those particular joints were lapped the way they are and can only figure that this was done to closely keep the plating against the inner frames and maintain the overall shape desired by the designers. I'm certainly no steel fabrication guy and have no experience in this field, but what I've just written seems to me to at least partially explain the variations of the plating, at least for this particular strake. I associate this in steel with the old "stealer" wooden planks that were used in ages past to fill in where a strake above and below would either leave a void or open space and could not be pulled either down or up and reshaped to fill that space. Not knowing in what order the hull plating took place, I could possibly see that this might have been the planking strake that was designed in the first place to be odd in shape just for this singular purpose.

Just a conjecture, nothing more.

Hank
Post Posted: Mon Jan 27, 2020 8:04 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
So most of the ship is welded, but some areas along the upper hull were riveted instead due to the plates being thicker and overlapping?[/quote]


Almost all of the long horizontal exterior hull seams were riveted. So the majority of the total length of exterior hull seams were riveted.[/quote]

Unfortunately, I cannot upload my diagrams showing welds, rivets, rabbets, overlaps, and scarfs here at a resolution that is visible. Stuff that is welded:

1. All transverse seams except in the upper four strakes midship.
2. The bow.
3. The forward 1-2 plates aft of the bow section below the waterline.
4. At the keel at the very stern.
5. Along the forgings and castings
6. At the aft end of the twin keels.
7. N strake at stern.

In all my looking at the plans, I have not been able to figure out the mindset at work on the hull. OK, they did not want to weld everything. But why does a single seam have multiple joints and transitions and even reversals of overlaps? The N-O seam, starts out butt welded, shifts to riveted N over O, flips to riveted O over N, then transitions to a rabbet joint, the width of the rabbet changes twice, then it switches to O over N riveted, then N goes on top, and finally at the stern, they are but welded.

The joints and transitions are extremely complex and must have been expensive to produce. But why? That goes way behind a mistrust of welding.
Post Posted: Sun Jan 26, 2020 8:43 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
Thomas E. Johnson wrote:
bigjimslade wrote:
I have been trying to find sources that address the welding v. riveting question. Dulin has a page on welding but it does not really address the question of why. None of the other standard references address it. If anyone knows of a source(s), let me know. I have asked in other fora to no avail.

We do know that there was some level of distrust of welding. When Liberty Ships and T-2 Tankers were breaking in half, weld quality received the blame initially. It turned out the quality of welds had little to do with it and poor quality steel that became brittle with cold and poor design for welding (e.g., hatches with square corners) were to blame. The latter is similar to the problem the Comets had.

On the Iowas, the bow is welded. All but the upper four strakes are welded end to end. The structural members are welded. The hull is welded where riveting would have been impracticable. And the Superstructure is welded.

So a lack of trust in welded joints does not appear to be the concern.

I have been puzzled that they butt welded the hull strakes but in much of the ship there appears to have been a distrust of butt joints. In the barbette supports, there are butt plates welded over the butt joints; something that is weaker than a simple but joint. Then, oddly, the turret supports are riveted.


So most of the ship is welded, but some areas along the upper hull were riveted instead due to the plates being thicker and overlapping?



Almost all of the long horizontal exterior hull seams were riveted. So the majority of the total length of exterior hull seams were riveted.
Post Posted: Sun Jan 26, 2020 6:05 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
bigjimslade wrote:
I have been trying to find sources that address the welding v. riveting question. Dulin has a page on welding but it does not really address the question of why. None of the other standard references address it. If anyone knows of a source(s), let me know. I have asked in other fora to no avail.

We do know that there was some level of distrust of welding. When Liberty Ships and T-2 Tankers were breaking in half, weld quality received the blame initially. It turned out the quality of welds had little to do with it and poor quality steel that became brittle with cold and poor design for welding (e.g., hatches with square corners) were to blame. The latter is similar to the problem the Comets had.

On the Iowas, the bow is welded. All but the upper four strakes are welded end to end. The structural members are welded. The hull is welded where riveting would have been impracticable. And the Superstructure is welded.

So a lack of trust in welded joints does not appear to be the concern.

I have been puzzled that they butt welded the hull strakes but in much of the ship there appears to have been a distrust of butt joints. In the barbette supports, there are butt plates welded over the butt joints; something that is weaker than a simple but joint. Then, oddly, the turret supports are riveted.


Lack of trust in welding was a concern. But welding offer advantages because it is faster, saves steel, and produces a lighter finished structure. So where production rate is of greater concern than durability, like building liberty ships faster than the Germans can sink them, the lack of trust is accepted as a necessary price to pay.

On capital assets like battleships, welding is also accepted in parts where the individual members are not highly stressed, or where failure would not be critical. Butt joints within each strake are not critical, because the butt joints do not line up across different strakes, even if one butt joint fails, the load will be transferee to areas of adjacent strakes where there are no joints, and the rip will stop.

Joints across strakes are critical, because the seams align across the top and bottom edge of all plates within a strake, If a welded seam fail at one location, it can propagate across multiple plates, leading to the entire seam unzipping.


So it is common for battleship hills started in mid to late 1930s to be a mix of welded and riveted parts. The percentage of hull that is welded appears to correlate with experience the navy had with welded ships, and the state of welding technology and availability of metal alloying elements required to make steel weldable in a country.

For example, on the Bismarck, most of the hull was welded. But the Germans had been building largely welded warship hulls since the 1920s, and had a lot of experience. But the torpedo defence system, which are expected to be subjected to the greatest load and experience the largest deformation, were still riveted.

On Yamato, parts of the hull outside the citadel was welded, but the hull around the citadel was riveted. The Japanese were also early adopters of welding, but japan had some bad experience with welding that required completed warships to be rebuilt replacing welded seams with riveted seams. So they became more conservative.
Post Posted: Sun Jan 26, 2020 5:48 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
bigjimslade wrote:
I have been trying to find sources that address the welding v. riveting question. Dulin has a page on welding but it does not really address the question of why. None of the other standard references address it. If anyone knows of a source(s), let me know. I have asked in other fora to no avail.

We do know that there was some level of distrust of welding. When Liberty Ships and T-2 Tankers were breaking in half, weld quality received the blame initially. It turned out the quality of welds had little to do with it and poor quality steel that became brittle with cold and poor design for welding (e.g., hatches with square corners) were to blame. The latter is similar to the problem the Comets had.

On the Iowas, the bow is welded. All but the upper four strakes are welded end to end. The structural members are welded. The hull is welded where riveting would have been impracticable. And the Superstructure is welded.

So a lack of trust in welded joints does not appear to be the concern.

I have been puzzled that they butt welded the hull strakes but in much of the ship there appears to have been a distrust of butt joints. In the barbette supports, there are butt plates welded over the butt joints; something that is weaker than a simple but joint. Then, oddly, the turret supports are riveted.


So most of the ship is welded, but some areas along the upper hull were riveted instead due to the plates being thicker and overlapping?
Post Posted: Sun Jan 26, 2020 3:52 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
With the Victory Ships I have some recollection that the frame spacing was too close, giving a rigid hull which then trying to work in a seaway created a lot of extra stress. Being a wartime project I suppose there was an "acceptable loss rate".
Post Posted: Sun Jan 26, 2020 12:10 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
I have been trying to find sources that address the welding v. riveting question. Dulin has a page on welding but it does not really address the question of why. None of the other standard references address it. If anyone knows of a source(s), let me know. I have asked in other fora to no avail.

We do know that there was some level of distrust of welding. When Liberty Ships and T-2 Tankers were breaking in half, weld quality received the blame initially. It turned out the quality of welds had little to do with it and poor quality steel that became brittle with cold and poor design for welding (e.g., hatches with square corners) were to blame. The latter is similar to the problem the Comets had.

On the Iowas, the bow is welded. All but the upper four strakes are welded end to end. The structural members are welded. The hull is welded where riveting would have been impracticable. And the Superstructure is welded.

So a lack of trust in welded joints does not appear to be the concern.

I have been puzzled that they butt welded the hull strakes but in much of the ship there appears to have been a distrust of butt joints. In the barbette supports, there are butt plates welded over the butt joints; something that is weaker than a simple but joint. Then, oddly, the turret supports are riveted.
Post Posted: Sun Jan 26, 2020 11:37 am
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
Apparently riveting was still used in European ship building as late as the late 1950s.
Post Posted: Sun Jan 26, 2020 8:54 am
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
I always thought all ship construction by 1940 or so was predominantly welded.....

This is very enlightening.
Post Posted: Sun Jan 26, 2020 7:53 am
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
One really tricky aspect of using masking tape to paint overlapping hull seams is at several locations on the Missouri, the direction of overlap abruptly reverses. The horizontal seam transitions from bottom strakes overlapping top strake abruptly to top strake overlapping bottom strake. But otherwise the strakes themselves continued without any vertical seams. It is impossible to abruptly transition from masking the top strake to making the bottom strake without leaving a discontinuity in the paint. I though about sanding away the discontinuity when I am done. But I found it was impossible to do without marring the intended horizontal strake overlap.

The way I found around it it to hold a piece of paper about 1/3 inch away from the model at the location where overlap reverses. You mask the overlap one way up to the paper. Spray until you get the depth of overlap right. The paper ensures where the transition is, the paint feathers to nothing rather than abruptly end leaving a discontinuity. Then move the paper to the other side of discontinuity, and make the side with the reverse overlap. This way, at the location where the reverse is, the paint making up the strakes feather into eachother.
Post Posted: Sun Jan 26, 2020 12:16 am
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
Referring to the above 2 posts re. hull painting techniques - I used that same technique with my 1:200 NEW JERSEY only I had a scaled plating pattern that was developed by another modeler for his 1:200 MISSOURI (Same Trumpeter kit) by drawing this up in CAD (3D Solidworks, I think). I used a wide fan brush with bottle paint and I believe I detailed this in my build over on Completed Models, etc. Using the brushed, flat, lacquer paint it only took a couple coats to achieve the weld lines that I had laid out with masking tape.

Welding, in regards to the IOWA Class, was minimal on the initial 4 ships actually completed, while KENTUCKY and ILLINOIS were almost completely welded with minimal riveting as things by 1944 onward had progressed a great way in accuracy, quality, and technique. I think this is fairly well documented in U.S. Battleships, an Illustrated Design History (Friedman), but it could be Battleships: U.S. Battleships in World War II (Dulin, Garzke, Sumrall).
Post Posted: Sat Jan 25, 2020 8:44 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
chuck wrote:
On 1/200 scale I used paint masking technique to produce what I consider realistic and scale accurate plating patterns on the Missouri. It takes maybe 5-6 coats of Tamiya spray can lacquer applied Fairey lightly to achieve it for midship underwater plating overlap, and 3 coats for bow and stern.

Regarding welding, there was not enough experience with welding in 1938. Welding was considered suspect with higher strength steel. Welds were considered intrinsically less suitable for containing battle damage in high value structures because tears in steel can rip right across welded seams, where as riveted seams form nature rip stops that prevents propagation of tears across seams.

The US also wasn’t the world leader in warship ship welding, the Germans and the Japanese were. It was well known the German and Japanese experienced major structure failures in welded members, and failed ships were rebuilt with riveted seams. The Germans had by far the most experience with welding in naval construction, and were comfortable using welding to a far higher extent in major warships than anyone else. But even they were not confident enough to use welding on very high strength steel


I used the same method on my 1/200 hull.
Post Posted: Sat Jan 25, 2020 2:27 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
On 1/200 scale I used paint masking technique to produce what I consider realistic and scale accurate plating patterns on the Missouri. It takes maybe 5-6 coats of Tamiya spray can lacquer applied Fairey lightly to achieve it for midship underwater plating overlap, and 3 coats for bow and stern.

Regarding welding, there was not enough experience with welding in 1938. Welding was considered suspect with higher strength steel. Welds were considered intrinsically less suitable for containing battle damage in high value structures because tears in steel can rip right across welded seams, where as riveted seams form nature rip stops that prevents propagation of tears across seams.

The US also wasn’t the world leader in warship ship welding, the Germans and the Japanese were. It was well known the German and Japanese experienced major structure failures in welded members, and failed ships were rebuilt with riveted seams. The Germans had by far the most experience with welding in naval construction, and were comfortable using welding to a far higher extent in major warships than anyone else. But even they were not confident enough to use welding on very high strength steel
Post Posted: Sat Jan 25, 2020 10:43 am
  Post subject:  Plating  Reply with quote
I've received some requests on information on plating. I am trying to put together a reference on this. Assembly the data requires piecing information from many different sources together. It is not practicable for me to do a giant document jump and provide anything meaningful.

I have come to the conclusion that the hull was largely riveted in a misguided belief that the greater flexibility of a riveted hull than a welded hull was necessary for a ship of this size. I have not come across any references to that effect but that is the only conclusion I can come to. Some of the strake plates are welded. The structural members are welded. So inexperience in welding does not explain why the navy went to the cost and time of riveting the hull.

Here is a photo of the bow. I have labeled the strakes. There are several Q and R strakes at the bow. The current top of the boot topping is slightly below the designed waterline. So the K1 strake would not have been visible at all. The M strake is at the waterline for most of the hull length.

In this zone between about Frame 40 to Frame 2 the strakes are arranged in an inverted clapboard manner where the lower strake overlaps the strake above. Just forward of frame 40, the N strake overlaps the O strakes but aft this reverses with the O strake overlapping the N strake. Farther aft they switch to a butt alignment. The lower side strake switch to a butt alignment in this region as well.

A feature that is not visible is that the thickness of the strake plates vary. They are all 1/4" at the bow. They tend to get thinner immediately aft then get thicker aft. The visible plates range from 7/16" to 1-1/4". There are chamfers at the thickness transitions so the thickness variations are not apparent.

For modelers at 1:200 - 1:350 scale the thickness of the overlaps are around 1/1000" (hardly visible). The butting seams midship are hardly noticeable on the ship until you get really close.

For most of the length, the M and N strakes have a scarf joint.

The same kind of arrangement is at the stern as well.

Attachment:
Bow.jpg
Bow.jpg [ 221.57 KiB | Viewed 363 times ]
Post Posted: Sun Jan 12, 2020 7:08 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
I know maybe 20 years ago Remington made an electrically fired sporting rifle with the idea of reducing lock time. Not sure what primers were used.
Post Posted: Sun Jan 12, 2020 7:08 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
Fliger747 wrote:
It looks quite tapered. How are they extracted?


It is very tapered. The primer automatically ejects when the breach opens.
Post Posted: Sun Jan 12, 2020 4:36 pm
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
It looks quite tapered. How are they extracted?
Post Posted: Fri Jan 10, 2020 1:15 pm
  Post subject:  Primers  Reply with quote
Here is a picture I took of a primer and a 7.62 case. They look similar to "assault weapons" types but are quite different in shape. A major technical difference is visible here. Note the dark ring at the base of the primer. That is insulation so that a circuit can form from the case to the center of the base. The center is not a percussion cap like on the 7.62 case and is smaller. The center is a plunger that can mechanically trigger the primer.

Attachment:
P1050521 Primer.jpg
P1050521 Primer.jpg [ 261.97 KiB | Viewed 160 times ]
Post Posted: Fri Jan 10, 2020 10:17 am
  Post subject:  Re: Calling all USS Iowa BB-61 class fans  Reply with quote
I'll go out on a limb and a-s-s-u-m-e that these drawings have all now been de-classified for public consumption.

I would hate to think that the Spublovians might have access to some of our most top secret tools and formulas :doh_1: :censored_2:
Post Posted: Thu Jan 09, 2020 3:20 pm

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