bigjimslade wrote:
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.
Attachment:
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.