Calling all Iowa-class (BB-61) fans

[Fliger747]

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".

[Thomas E. Johnson]

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?

[chuck]

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.

[chuck]

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.

[bigjimslade]

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.

[BB62vet]

BJS wrote:

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

[Fliger747]

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.

[bigjimslade]

Below the waterline there are several places where strakes divide. This creates a T-joint where, say, the end of a G-strake plate butts to a G-strake and H-strake plate.

Longitudinal seams are lap joints. The transverse seams are but joints.

Imagine the mess this creates as the corner where two welded butt joints are crossed by a lap joint (with all plates the same thickness).

[stevegallacci]

After a long pause, I'm getting back into working on my Trumpeter conversion of the Iowa in spirng of '43 configuration. Have pretty good images and such for most of the details, including the new "Anatomy of the Ship" book. A little finishing question (may have brought this up here some years ago before I dropped out). It appears that there was unpainted (?) linolium (?) on the unplanked decks during the '43 shake down. Only have a few photos that suggest it, most clearly in the 40mm tubs and maybe elsewhere. Any insight?

[BB62vet]

Steve Gallacci wrote:

It appears that there was unpainted (?) linolium (?) on the unplanked decks during the '43 shake down. Only have a few photos that suggest it, most clearly in the 40mm tubs and maybe elsewhere. Any insight?

Without seeing those photos my comments are simply generalized - I seriously doubt the Navy would have sent the ship to sea without proper painted exterior surfaces. That simply (from my naval experience) wasn't done. Linoleum is an INTERIOR flooring material, not exterior. As far as I know, 40mm gun tubs would have been painted with deck gray or whatever camo paint the shipyard was instructed to use at that time.

Hope this helps,

[stevegallacci]

Steve Gallacci wrote:

It appears that there was unpainted (?) linolium (?) on the unplanked decks during the '43 shake down. Only have a few photos that suggest it, most clearly in the 40mm tubs and maybe elsewhere. Any insight?

Without seeing those photos my comments are simply generalized - I seriously doubt the Navy would have sent the ship to sea without proper painted exterior surfaces. That simply (from my naval experience) wasn't done. Linoleum is an INTERIOR flooring material, not exterior. As far as I know, 40mm gun tubs would have been painted with deck gray or whatever camo paint the shipyard was instructed to use at that time.

Hope this helps,

I was wondering about the use of linoleum on decks. However, going from period photos, famously the overhead shots, it appeared that the gun tubs in particular had that brownish color, and what appeared to be thin joint strips. Maybe the tubs were still in primer and the strips were just bright weld lines. However, in later shots when she was out to sea, the tubs, at least, were still in a dark (and depending on the color quality of the print) brownish color. Then, whatever color it was, it was clearly darker than the top side color on other items.

Not looking for an argument, just a clairification of what actually was, rather than what should have been. Been doing research for a lot of years on other subjects, and what was versus what should have been often come up.

[Fliger747]

Was the deck planking painted at the time?

[chuck]

Linoleum is not strictly an internal deck material. The British used linoleum in some of the exterior decking on superstructures, while the Japanese used linoleum almost exclusive as decking material for the hull on destroyers and cruisers. In the IJN only battleships Ana carriers get wooden deck planking.

[Fliger747]

Just hadn't seen it exterior for USN. My understanding is that some ships removed it as well as interior paint to reduce fire hazard.

[BB62vet]

I think there was some question a while ago on older U.S.N. battleships about the use of linoleum (brown) in exterior spaces for deck covering. Don't know there was any final proof or answer to that thread.

Steve - can you provide a copy of the photos you mentioned? It's quite possible that the ship still had primer paint in the gun tubs when the photo was taken although a dk. brown primer paint I've not come across; who knows what was done in the '40s!

[Fliger747]

Any color photos of the era would be highly suspect. Reds might be rendered muddy browns with age.

[Guest]

Was the deck planking painted at the time?

During the shakedown cruise, the decks had not yet been painted, yet another reason to model the Iowa in that time frame. More interesting than most of the wartime schemes. But, I also wanted to do it as originally designed, and plan to build the Missouri in end-of-war configuration to show the evolution. Given enough time I considered doing the other sister ships at other times in the class's history. Also doing the 1/350 Yamato in its shakedown cruise configuration (though am doing the Musashi and Shinano in fantasy configurations)

[bigjimslade]

The only non-wood exterior deck covering I am aware of is the black rubber mats placed on top of adhesive over the wooden decks in the vicinity of Turret No. 3.

I have seen no signs of British style covering over the exposed steel.

[Fliger747]

Is there a difference between the original design and the original construction? How much change was there between shakedown and trials and initial service?

BJS: What was the purpose of the mats?

[chuck]

I believe in the original design, the area between funnels were intended for stowing the typical prewar complement of boats. These would have been serviced by cranes located on either side of the aft funnel. The base for the crane and the boat chocks were actually installed before the decision was made to build the mid ship triplex bofor tower over them. According to Friedman, when the midship bofor towers were removed from the Iowa and New Jersey during the 1980 modernization, the workmen discovered the original boat chocks and crane base still there under the tower.

When the Iowa was ran her trials in March 1943, she had a different arrangement of bofors and oerlikon than what would become standard on the lowa class. She had no oerlikon tub on top of the bullnose. instead of a pair of bofor tubs in front of A turret, she had a triangular oerlikon tub there for three oerlikom mounts. The base of the triangular oerlikon tub were uncovered when as part of museum sponsored restoration, the deck planking were replaced. The main turrets didn�t have any AA guns on them, and the pair of bofor tubes flanking aft end of the superstructure were not there either. In their place were 2 oerlikon mounts. These original features were all gone by nov 1943, when she ferried FDR to the Tehran conference.