Calling all Iowa-class (BB-61) fans

[Fliger747]

You are saying that the aft hull is asymmetric?

[Fliger747]

The hull form lines as shown in "Garzke and Dulin" do not indicate an asymmetry. The original hull form was hollowed out the area in front of the outboard propellers after model basin testing.

[chuck]

All information I have shows the hull shape is symmetrical but around the skegs the shapes are complex. At the point where outboard shaft exits the hull, the hull side is straight and inclined above waterline and curved in a convex manner all the way to the keel below waterline. At the of the outboard screw, the hull side is curved continuously in a convex manner to near the level of the screw, when it transition to concave.

More subtlety, however, references say the orientation of the propeller shafts are not completely symmetrical. The two port shafts exits the hull at a slightly greater angle below horizontal than the two starboard shafts, and the port outboard shaft toes outwards slightly more than the starboard outboard shaft. This is caused by the fact that the turbines for the 4 shafts are located front to back in the sequence of starboard outboard, port outboard, starboard inboard and finally port inboard. So the shaft for each propeller Has a different different length to run to its turbine compared to its counterpart on the other side.

[bigjimslade]

You are saying that the aft hull is asymmetric?

The shape of the hull is symmetric. My meaning is that the slope of the tunnel inside the twin keels is not the same as the the slope of the hull outside.

You can see on the Tamiya and Trumpeter kits that, if you cut the twin keels off, you'd have a constant hull curve upwards. On those kits the bottom of the twin keel is roughly the same width throughout. On the Iowas, the thickness gets much thicker forward and thinner aft.

Refer to the pictures I posted above of the kit and a computer image generated from the Iowa class plans. Compare the shape of the half siding on the baseline in the computer image with the same on the kit.

Here I have a sketch of the flat area at the bottom of the Trumpeter hull in read and below I have the actual shape of the flat area of the bottom of the Iowas as taken off the table of offsets.

[Fliger747]

After a bit of brain circulation figured out what you were referring to. The mold for this hull must have cost many hundreds of thousands of dollars? Perhaps it is just scaled up as you say and CNC'd in a larger size?

[bigjimslade]

You are saying that the aft hull is asymmetric?

I discovered that the hull plating is not entirely symmetric�and I'm not talking about hull openings.

I have not figured out why yet.

[Fliger747]

In what way is the plating asymmetric? Below or above the WL, for or aft etc? I noticed on Missouri that a different plating was "added" when the booms for the Jacob's ladders were removed. As Chuck pointed out, the internal arrangement is not symmetrical, though the depth of the side protective scheme would tend to reduce such necessity.

[Thomas E. Johnson]

Having just compared the hull stern area below the waterline of the MENG Missouri to the Trumpeter & Tamiya models, I see now where people are saying the hull is off. Unfortunately my build is to far along to correct, and I wouldn�t attempt surgery anyways. I still think it�s close enough where most folks won�t be noticing.

It would be nice though if someone were to create some 3D printed �drop in place parts� to be glued onto the hull to create a more correct shape.

[Fliger747]

Unfortunately it's a matter of removing materials. Does this paint make my Battleship's ass look fat? Some can be added at the bow, but the stern requires major liposuction.

[Thomas E. Johnson]

Unfortunately it's a matter of removing materials. Does this paint make my Battleship's ass look fat? Some can be added at the bow, but the stern requires major liposuction.

Yeah, and it�s not worth the aggravation. Now if someone were to make a 3D printed drop in place lower stern, that just involved cutting away the molded plastic at the waterline and just behind the #3 turret, and dropping in a new lower stern, then were on to something....

[bigjimslade]

In what way is the plating asymmetric? Below or above the WL, for or aft etc? I noticed on Missouri that a different plating was "added" when the booms for the Jacob's ladders were removed. As Chuck pointed out, the internal arrangement is not symmetrical, though the depth of the side protective scheme would tend to reduce such necessity.

So far I have found that the C strake (below the waterline) is different P/S. The difference does not appear to be the result of an opening.

[chuck]

Where did you get the strake diagrams?

[bigjimslade]

Where did you get the strake diagrams?

I have to assemble that from a lot of data collected from different places. The mold loft data is frequently unreadable. 3s look like 5's. 6's look like 0s. So I have to do trial and error with data points. I have to debug the points.

Then I have to compare with other plans I have collected.

From that I generated the diagram shown. I have not finished the entire hull.

[Fliger747]

Under the general heading of "Wild Ass Guess" with no corroborating evidence (no longer a modern requirement) would be that for structural reasons the butts of side plates were alternated such that they weren't aligned at the same frames?

[bigjimslade]

Under the general heading of "Wild Ass Guess" with no corroborating evidence (no longer a modern requirement) would be that for structural reasons the butts of side plates were alternated such that they weren't aligned at the same frames?

And the strake ends appear to generally be off a frame, typically either 21" or 12". My guess at this point is the reason is to allow butt plates to be inserted.

Let me throw out another detail that is not apparent from must plan sets or hull lines shown in the books.

There are a lot of linear sections in the hull. From frame 55 to Frame 171 the sides are straight (but at various angles. After Frame 171 the upper part of the frame starts forming knuckles. For illustration, this is Frame 188. There is a distinct knuckle at each segment.

[chuck]

I noticed the knuckles on drawings, and looked carefully on the New Jersey, Wisconsin and Iowa for them. I think for all practical purposes the knuckles are too subtle to be noticed on the real ship.

[Fliger747]

The butt straps joining the 60# plate in way of the citadel and above the WL was not in my understanding joined at frames. Yes the knuckles are shown in various drawings and would be I suspect a feature to speed production, requiring less compound rolling of the shell plating. a time consuming process requiring some expertise. Such detail design was often done by the lead production yard with mind to ease, materials and speed of completion.

[bigjimslade]

The butt straps joining the 60# plate in way of the citadel and above the WL was not in my understanding joined at frames. Yes the knuckles are shown in various drawings and would be I suspect a feature to speed production, requiring less compound rolling of the shell plating. a time consuming process requiring some expertise. Such detail design was often done by the lead production yard with mind to ease, materials and speed of completion.

Interestingly, the knuckles do not match the strake edges. In most places the edges are roughly parallel but offset (by as much as a foot). In others, the strakes go across the knuckles.

[Fliger747]

One always wonders if this was due to design or happenstance? Certainly the design was well along when it was discovered that Bu Or designed a turret and rotating assembly over a foot larger than Bu C&R had allowed in their hull design. Certainly a plate formed with a knuckle has more longitudinal stiffness than one without. Perhaps it was advantageous to not knuckle them at the joint?

[chuck]

It seems to me if the knuckles exactly align with strake edge, then that would complicate riveting because the two rows of rivets would be at a slight angle to eachother. It would be easier to fabricate to put the crease for the knuckle on the interior of a plate.