Calling all Iowa-class (BB-61) fans

[Fliger747]

My WAG is that it's easier to get the frames to fit the shell plating than get the shell plating to fit the ribs.

[bigjimslade]

Here's one of the Iowa. The hull plating at the side is nearly to the 3d deck and has no framing. Framing is being attached at the bow but notice the frames are not supporting anything. The internal structured added stiffness but did not hold the shell together.

The highest priority in construction was the machinery spaces. The transverse bulkheads in that area were erected as soon as the the shell was wide enough to accommodate them and the holding bulkhead was added to the side.

Pictures show the machinery spaces up to the third deck before the bow was ever started.

In some cases the shell was way ahead of the rest of the ship in the vicinity. In others, it was at the same pace.

[chuck]

But is the scaffolding holding up the shell plating?

[Fliger747]

I don't think so, as the ship was riveted (mostly) somebody has to work on both sides. I wonder if some of the seemingly strange jointing and lapping had to do with this construction method?

[bigjimslade]

I wonder if some of the seemingly strange jointing and lapping had to do with this construction method?

Without computers, it would be effectively impossible to design frames for the hull shell that could take into account the myriad of joints and joint types as well as different plate thicknesses. Even with a computer, it would be impracticable to design such frames while taking into account the amount of error that would occur in normal construction. A single frame can have more than 60 notches cut into to it for joints. Multiply the margin error by sixty and one can see the problem frame and bulkhead construction would create.

Instead the hull served as the template for cutting the frames. The system of construction was backwards from that used in the age of sail.

If the hull plating were flush and welded, the weld gaps provide sufficient tolerance for small deviations.

[bigjimslade]

Here is a structural detail that did not make it into the recent book. The lower part will be familiar but the upper part may not. This is the forging for transmitting the force of the rudder to the ship.

The rectangular area forms part of the ship's hull. At the center rectangle is its 2-1/2" thick. It was machined so that it is 1-1/2" at the middle rectangle and 1-1/8" at the edge. It is actually 4 plates. Draw lines from the outer corners to the inner corners and extend them to the center to get the cut lines.

The diagonal line shown going through each plate marks the limit of the half siding where the hull bottom is flat in cross section.

The cones at the top poke up through the first platform where the rudder machinery is located. Frames and longitudinals pass over the plate and join the central forging. The horizontal structure with moon curves supports them at their ends.

The entire assembly was welded and welded to its neighboring plates.

This an example that refutes the idea that that hull is riveted because the designers did not trust welding. In fact, the key structural parts of the hull shell are welded.

It also illustrates some of the labor-intensive construction that went into the ships. Take a 2-1/2" plate. Bend it to shape. Machine it in steps down to 1-1/8. Weld it in place. Then machine the edges to match the thiner plates surrounding it.
That's a lot of work.

I guess the $1000 toilet seat is nothing new in defense projects.

[bigjimslade]

Here's a plan that I found that may be of use to modelers. It is for asbestos mats on bridge decks. Someone had asked about the deck covering previously. I have no idea of what the color would be. The asbestos mats we used in chemistry were white.

This the highest resolution I can post here.

[chuck]

Here is a structural detail that did not make it into the recent book. The lower part will be familiar but the upper part may not. This is the forging for transmitting the force of the rudder to the ship.

The rectangular area forms part of the ship's hull. At the center rectangle is its 2-1/2" thick. It was machined so that it is 1-1/2" at the middle rectangle and 1-1/8" at the edge. It is actually 4 plates. Draw lines from the outer corners to the inner corners and extend them to the center to get the cut lines.

The diagonal line shown going through each plate marks the limit of the half siding where the hull bottom is flat in cross section.

The cones at the top poke up through the first platform where the rudder machinery is located. Frames and longitudinals pass over the plate and join the central forging. The horizontal structure with moon curves supports them at their ends.

The entire assembly was welded and welded to its neighboring plates.

This an example that refutes the idea that that hull is riveted because the designers did not trust welding. In fact, the key structural parts of the hull shell are welded.

It also illustrates some of the labor-intensive construction that went into the ships. Take a 2-1/2" plate. Bend it to shape. Machine it in steps down to 1-1/8. Weld it in place. Then machine the edges to match the thiner plates surrounding it.
That's a lot of work.

I guess the $1000 toilet seat is nothing new in defense projects.

Rudder Bearing V2 02.jpg

That doesn�t refute it at all. Whether a hull structure is key does not say whether it is expected to be highly stressed either with normal or shock load in service, or whether the joints are expected to flex or deform.

We know even the Germans, who accepted welding much earlier, and to a much higher degree, than the US or anyone else for large warship construction, welded the entire hull of the bismarck class everywhere but the torpedo defence system because the bulkheads there were expected to see the highest shock loads and greatest deformation anywhere in the hull. They trusted welding around the rudder but didn�t trust welding where stress is really high

In a capitalship the strength deck, bottom and the strokes of hull side shell strakes close to them between end turrets experience the greatest load in rough sea, while the torpedo defence system expthe greatest deformation. So on the Iowa these were all riveted.

[Fliger747]

Several German Capital ships had their stern sections cleanly fall off due to damage. I believe even Bismarck ended up on the sea floor minus her stern section.

[BB62vet]

Jim,

Regarding your plan for the asbestos bridge/conning tower level deck mats:

Thanks for posting! Very interesting. One note - they are WWII era only, as the bridges were added/modified after this drawing was published. I couldn't find any dates due to the low res. of the picture, but I doubt any of this applied post-war. We certainly never had any in the late 1960s. My guess as towards color would be a med/dark brown or possibly deck gray/black.

Hope this helps,

Hank

[bigjimslade]

The date on the plan is 11-16-42. Unfortunately, I cannot post here at a high enough resolution to read it. It's after the design for the Missouri and Wisconsin but before the New Jersey and Iowa were updated.

It would be great to know what color these were.

[Fliger747]

Is there any evidence these were used on the Iowa's or any other capital ship?

[BB62vet]

Jim,

Thanks for sending me the .tif file - I am still unable to make out some of the very small text and did not see any material descriptions other than asbestos. I also did not find any color or descriptions of painting instructions, etc. although that could be there (just illegible). The date is 11/16/42 and various details on the drawing indicate which of the ships that particular detail refers to.

Hank

[bigjimslade]

I am still unable to make out some of the very small text and did not see any material descriptions other than asbestos.

Sadly, the person doing the microfilming was high on LDS at the time.

[Fliger747]

It's a popular church group in Utah.

[BB62vet]

[bigjimslade]

LDS?

You folks need to watch more Star Trek!!!

https://www.youtube.com/watch?v=pgHxFNFWlZc

[chuck]

Load Duration Curve

[bigjimslade]

On the Iowa and NJ, the bottom edge of the boot topping sloped up towards the stern so that it was 6' 11-1/2" thick at the bow and 29-1/2" at the stern.

On the Missouri and Wisconsin the boot topping was 41-1/2" wide the entire length.

The painting instructions suggest that the Missouri and Wisconsin sat around 20" deeper than the Iowa and New Jersey.

[chuck]

On the Iowa and NJ, the bottom edge of the boot topping sloped up towards the stern so that it was 6' 11-1/2" thick at the bow and 29-1/2" at the stern.

On the Missouri and Wisconsin the boot topping was 41-1/2" wide the entire length.

The painting instructions suggest that the Missouri and Wisconsin sat around 20" deeper than the Iowa and New Jersey.

Was the difference in boot topping width present during WWII?

Back of nevelope calculation suggest 20" of added imersion would correspond to 3000 tons of added displacement. were Wisconsin and Missouri 3000 tons heavier?