Calling all New Orleans-class (CA-32) fans

[CWatson]

It is my understanding after reading this thread that of the Trumpeter 1/700 kit. the San Fransisco is the most accurate compared to the real ship and the New Orleans is a close second?


Thanks again,
CW

[Dick J]

It is my understanding after reading this thread that of the Trumpeter 1/700 kit. the San Francisco is the most accurate compared to the real ship and the New Orleans is a close second?

The 1942 San Francisco, Astoria and Minneapolis are all close to accurate. However, each needs detail corrections. New Orleans is just a bit less accurate, but is still close. Quincy and Vincennes have serious issues, while the Tuscaloosa kit is a clone of the Quincy, which is wrong for Tuscaloosa. She was closer to the San Francisco, but still had significant differences. The 1944 San Francisco kit had its own issues. While most of the problems with these kits can be corrected, it is frustrating that you have to do that. If you want to do Tuscaloosa, though, start with the '42 San Francisco, or the Astoria or Minneapolis kits. That is easier to correct than the actual Tuscaloosa kit.

[CWatson]

Dick J,

Thanks for the answers. So the Astoria is pretty close? I have the 42 San Fransisco and BOOB. Hearing the Astoria kit is close is good news since I can get on and finish with here camo scheme (MS 12 Mod?).

What changes would be needed on the Astoria kit?


Thanks,
CW

[Dick J]

It is more meaningful to list ship differences than kit differences. However, one issue with the San Francisco kit is the back edge of the hangar roof. San Francisco was the only one of the sisters where the rear of the hangar roof extended beyond the edge of the structure walls. (All originally had extensions under the boats, but these were removed with the boats very early in the war.) The kit depicts this, but incorrectly mounts a splinter screen along its length. The only splinter screens back there in '42 were the tubs for the 20MM. That said, some of the other parts in the kit are aimed more at San Francisco than her sisters. For example, Astoria didn't have the splinter screens at the back of the bridge level with the 1.1" guns. http://www.navsource.org/archives/04/034/0403412.jpg San Francisco had a splinter screen across the back that essentially connected the gun tubs, and the kit piece is molded with this. There were other minor variations on the splinter screens of this bridge level that can be made out in the referenced photo.

And as I already mentioned, on Astoria, the hangar roof didn't overhang the back of the structure (except directly under the 20MM tubs). Astoria, San Francisco and Minneapolis all had small rangefinders mounted on the back of the hangar structure extending out over turret 3. On San Francisco, it was at the level of the hangar roof. On Astoria, it was above that level (http://www.navsource.org/archives/04/034/0403406.jpg) while on Minneapolis, it was below the level of the hangar roof. Astoria only received her first 10 20MM guns between Coral Sea and Midway, but had the last two (either side of the "birdbath" rangefinder forward) added immediately after Midway. At the same time (after Midway), she added the FC (MK-3) radar to the main battery directors and received directors for the forward 1.1" guns. When she was lost, the after 1.1 director tubs were still empty. Of course, San Francisco carried the flat-faced 8" gun turrets while the faces of the turrets on Astoria and Minneapolis were curved top-to-bottom. Both types of turrets are included in the kits. Another minor difference was the positioning of the foremost 20MM guns - the ones at the O-1 level forward of the elevated 5" mounts. On San Francisco and Minneapolis, the outboard splinter screen for this gun aligned vertically with the bulkhead of the underlying structure. On Astoria, the tub was extended out, overhanging the bulkhead and moving the gun more in front of the 5" mount. Minneapolis had these guns moved outboard during her post-Guadalcanal repair/modernization. San Francisco did not.

One other point, at Guadalcanal, all three (Astoria, Minneapolis and San Francisco) were all in MS-11, modified with navy blue paint replacing the sea blue. The only ships of the class wearing MS-12 (mod) in the Pacific were Quincy and Vincennes. Tuscaloosa also had MS-12 (mod), but not while she was in the Pacific.

Hope this helps.

[CWatson]

Hope this helps.

It does, very much and I would like to thank you for taking the time to post it.



CW

[scots navy]

My next build is the 1944 San Francisco so I have been doing research...so far so good until I got the floating dry dock 44 San Francisco plans which have me baffled by the fire control set up shown in the plans. They show fore and aft mark 31 directors with mark 3 fire control radars for the 8 inch main battery which makes sense and closed top mark 33 directors with mark 25 radars for the (8) open 5/25 guns which also makes sense but when I got to the mark 51 directors I get lost. I've always assumed a 1 to 1 relationship of mark 51 directors to 40 mm mounts, a lot of fellow ship modelers I've asked thought the same thing. The plans however seem to show 10 mark 51 directors to only 6 quad 40 mm mounts. The plans also show 4 mark 24 "target designators" which I've been unable to find any reference to. As I dug deeper I did find reference to mark 51 directors used for close in support of open 5 inch mounts. While this has little or nothing to do with building an accurate 1/700 trumpeter 44 San Francisco I would be curious to know if anyone in this group can clear up my confusion as to how the fire control system on the 44 frisco actually worked. One further point to my build is that while the 44 trumpeter San Francisco kit includes the same open mark 33 directors as the 42 kit, all the pictures I've seen show it as having the closed director by 44. Fortunately 3D offers both the closed and open top versions of the mark 33 director. For me a large part of the enjoyment of building ships is the knowledge I gain along the way about how the ships systems actually worked. Anybody know anything about this subject?

[Dick J]

The first 5 New Orleans class ships were built with MK-28 AA directors. Only Quincy and Vincennes were equipped with MK-33's. The main difference was that the MK-33 had power drives while the MK-28 was hand-cranked. That meant that the MK-28 could not add the weight of radar and still be hand-cranked at a speed that could keep up with target aircraft. So in order to add radar, the directors were upgraded to MK-33's; CA's 32, 36 and 38 during their 1943 post-Guadalcanal repairs/modernizations while CA-37 received hers in early 1944, The fully enclosed model was the only one in production at the time, and fully enclosed was thought to be necessary anyway. So when the San Francisco refitted in late 1944, she upgraded the radars to MK-25's, but the directors themselves were not changed at that time. By late 1944, the Japanese tactic was to overwhelm the director systems on US ships by having the attacking aircraft outnumber the directors on the target ship. There was no easy way to add more MK-33's for both space and weight reasons. In fact, the MK-25 radar was chosen for being lighter than the alternatives, allowing the added weight of the smaller MK-51's on the topweight-limited ships. The USN had decided that a 5" gun directed by a MK-51 was more effective than one guided just by the eyeballs on mount, so 4 MK-51's were added to allow the 5" to engage more than two aerial targets (only two MK-33's) in a pinch. I am not sure what the "MK-24 target designator" was.

[DrPR]

Looking over ship plans I have found several references to main battery and secondary battery "target designators" and "target designation transmitters" (TDTs). Are these the same thing?

I have found photos on Navsource of Mk 1 TDTs on some battleships. I have photos of the Mk 23 Mod 0 TDTs on the USS Little Rock CG-4 museum ship. I have found no information or drawings for "target designators."

Anybody have information about these?

Phil

PS: I have posted images of the Mk 23 Mod 0 TDT here:

viewtopic.php?f=27&t=70810&start=20

Go back to 20 Jan 2016.

[scots navy]

Thanks for answering my guestions about the u.s.s. San Francisco's fire control. Your answer of course raised more questions. Am I correct in thinking then that a Mark 33 director with mark 25 radar can only direct one plane at a time? with more directors than guns does it work like a switchboard with someone linking up the best director with the best gun? In looking at other models ie. the South Dakota I realize there are more directors than guns. I'm assuming a mark 51 director can link up with a 5" gun or a 40mm gun. Still curious...

[scots navy]

my previous post should say that can one mark 33 and on mark 25 only direct one "gun" at a time? Same fingers I build with I type with. go figure.

[DrPR]

The director signals go to a switchboard in gun control, and the signals to the guns go to the same switchboard. They could switch one or more guns to any of the directors. The Combat Information Center or Forward Air Control decided which targets to engage and with how many guns.

Generally there were main battery directors for the big guns, secondary battery directors for the next smaller guns and anti-aircraft battery directors. Each director was more or less optimized for a particular type of gun. However, in my day we could switch any director to control any gun.

At the end of WWII some 40mm mounts had their own radar control director mounted on the guns.

I think the target designators or target designator transmitters (TDTs) could be used to aim larger directors at specific targets.

Phil

[bwross11]

So, I have a little bit of a mystery; in the picture below, what is that attached to the aft starboard side of the superstructure? This is from Dec 42 upon her return from Guadalcanal.



Better pictures from her departure in May 42 seem to indicate this was on the port side as well, but apparently by the next pictures in Dec 42 after her return the port side was gone, you can see lighter paint hinting that the thing was removed.

So, any ideas? And, if you have any ideas, do you know of any better pictures, maybe from a sister that could aid in building a replica?

thanks
Bruce

[DavidK]

So, I have a little bit of a mystery; in the picture below, what is that attached to the aft starboard side of the superstructure? This is from Dec 42 upon her return from Guadalcanal.



Better pictures from her departure in May 42 seem to indicate this was on the port side as well, but apparently by the next pictures in Dec 42 after her return the port side was gone, you can see lighter paint hinting that the thing was removed.

So, any ideas? And, if you have any ideas, do you know of any better pictures, maybe from a sister that could aid in building a replica?

thanks
Bruce

I sure don't know. They look like fins that you'd find in heat exchange designs, but no reason for cooling fins there. Perhaps they were a poor man's attempt to reduce air flow over the top of the aft main turret for some reason (i.e. they were wind baffles)? Maybe to improve conditions for an AA battery. Then they were later removed because they really didn't do a very good job of it? The angular superstructure shape aft of the hanger suggests air could wrap around the hanger and converge behind the aft bridge about where the aft turret is when the ship is moving.

Dave

[Angeliccypher]

Looking closely at the photo and realizing the angle it was taken at, could they be hinged panels of some kind that are sitting open?

[Rick E Davis]

I don't have a clue what this structure is, but I couldn't find it on any of her sisters.

Also, whatever it is, stayed with her through at least October 1944 on both portside and starboard side views. But, what is really interesting, is that it appears to be located at a lower height from the main deck by 1944!!!

Several sisters had Life Floats located in this general area, but among my limited number of SAN FRANCISCO views, she doesn't have floats there.

The views below date 4 December 1942 at Pearl Harbor, 9 November 1943 off Hawaii , and 13 October 1944 and 15 October 1944 ay MINY.

[MatthewB]

This is just a thought about those thingies on the side of the hangar on the SF (great, another thing to take into account on my re-build of that ship).

They look like sleds of some type to be pulled in the water, with the fins made to stabilize them.

Could they then be a part of the sleds used to recover the float-planes?

If you had one of those on the end of the netting, it would keep the netting flowing out directly behind it, and help keep the wake from flopping the netting about.

I have absolutely no idea about this, I am just shooting at the sky for possibilities.

MB

[bwross11]

MB,
That's what I thought at first as well. But, then thinking about it a couple of thoughts came up. I think that they are placed outside of the reach of the cranes. If they are made of some material substantial enough to be used in the sled job they'd be relatively heavy. That means, those things would have to be manhandled up and down by the crew; at sea that could be a challenge.
The problem with modeling them without more substantial pictures is that it appears that there may some shape to them other than just a flat sided shape. Since the model I'm working on is destined for museum display I need to either get the shape right, or just not include it.

Rick, once again, thanks for the pictures. Question for you sir; in your library of pictures of SF (understand it's limited) do you have any pictures that show the area immediately aft of the second stack? I know there was an incinerator in that area but don't know exactly what it looked like.

And the mystery goes on.......

thanks
Bruce

[Rick E Davis]

Sorry Bruce, I don't have any overhead shots close enough to provide any good details of the area aft of the stack.

I have some info for a sister USS TUSCALOOSA that I can't post because of the size, but I don't know if that applies to SAN FRANCISCO since it seems many of the NEW ORLEANS class varied from their sisters.

[Dick J]

The area aft of the second stack did vary somewhat. The navy yard built ships were largely similar as built. (CA's 32, 34. 36 and 38) San Francisco differed from the other three mainly in the turrets and related armor thicknesses. But the four were otherwise similar. All but New Orleans had similar bridge mods and similar early war configs. Aft of the second stack, all four had a single rectangular "mushroom" vent that ran athwartships. The trash burner was a squarish box forward of the vent to starboard of centerline. The trash burner stack was the starboard pipe up the back side of the second stack.

Tuscaloosa had two square vents in this area that angled back and down. The trash burner was between the two vents adjacent to the port vent. The stack crossed centerline and was still the starboard pipe up the back of the second stack. Quincy and Vincennes also had two vents, but they were enclosed in a larger structure that extended more to starboard than to port. Their trash burners were forward of the port side vent and their trash burner stacks were the port side pipe up the back of their second stacks.

Of course, once war modifications set in, all bets were off for uniformity.

[bwross11]

Dick good information, thanks.

Do you think that the basic shapes of the incinerator would have been fairly common, location withstanding? I knew that it vented up the starboard stack pipe, but I'm thinking that if I can find at least some representation of the basic shapes I can at least fill the space with some kind of representation.

Any thoughts on the mystery structures on the aft superstructure?

best,
Bruce