Calling all Skipjack-class (SSN-585) fans!

[Woodstock74]

Yes, the five-bladed propellers had a diameter of 15'0". There were several seven-bladed propellers, some with 15'0" and some 12'4". If you want more information, look up the following numbers up on https://fsg-20-ship-marine.parttarget.com/

SSN588-203-2113387
SSN588-203-2113387PC1
SSN588-203-2500463
SSN588-203-2540029
SSN588-203-2478480
SSN588-203-4352714PC1
SSN588-203-4252643PC1

Note that these are for the Scamp "class" (i.e. every submarine in the Skipjack class except the Skipjack herself), which had different propulsion machinery. However, I doubt the Skipjack's propeller was any different.

I guess this begs a question...it appears one could order these screws. What else uses this design? Or, why would this be in the public domain?

[Vepr157]

I guess this begs a question...it appears one could order these screws. What else uses this design? Or, why would this be in the public domain?

It's a site intended for the companies that supply the Navy, so you would not be able to order anything off that website. Besides, they were made by the Navy's own propeller foundry in Philadelphia, so it's not like you can order them from a private company. Propellers are very specifically made. Even if they have essentially identical dimensions as propellers for other classes, like the seven-bladed propellers for the 598 and 616-class SSBNs, they will be marked as suitable for only a single class.

As to why it's in the public domain, this stuff isn't classified. All propellers up to the Sturgeon class have declassified exterior surfaces (the interior is still classified), so you will find that Los Angeles and Ohio class propellers are listed, but there is much less information in the listings.

[Woodstock74]

I guess this begs a question...it appears one could order these screws. What else uses this design? Or, why would this be in the public domain?

It's a site intended for the companies that supply the Navy, so you would not be able to order anything off that website. Besides, they were made by the Navy's own propeller foundry in Philadelphia, so it's not like you can order them from a private company. Propellers are very specifically made. Even if they have essentially identical dimensions as propellers for other classes, like the seven-bladed propellers for the 598 and 616-class SSBNs, they will be marked as suitable for only a single class.

As to why it's in the public domain, this stuff isn't classified. All propellers up to the Sturgeon class have declassified exterior surfaces (the interior is still classified), so you will find that Los Angeles and Ohio class propellers are listed, but there is much less information in the listings.

Wasn't planning on ordering one...but it IS tempting...

Not surprised they are bespoke, just confused why they'd bother listing parts for scrapped sub classes. Granted, it would make sense if they carry over to current. But the screws clearly do not...

[Vepr157]

Wasn't planning on ordering one...but it IS tempting...

Not surprised they are bespoke, just confused why they'd bother listing parts for scrapped sub classes. Granted, it would make sense if they carry over to current. But the screws clearly do not...

I think it's just some generic catalog that has info carried over from old parts. There are even listings for the WWII-era Fleet Boat propellers (which were still manufactured post-WWII for some of the GUPPYs, Fleet Snorkels, etc.).

[Woodstock74]

Never mind, think I found the answer!

[razgrizbsg27]

I'm Building the Moebius Skipjack in 1/72, and I'm planning to portray her as one of the Skips late in their life, probably USS Shark or USS Sculpin. So that means at least to my knowledge, a Towed array, and some of the extra blisters on her deck (PUFFs maybe?) and possibly a 7 bladed screw? Although I'm not sure if all the Skipjacks got 7 blades later or not.

I'm planning to either 3d print or make out of plasticard the Box that reels the towed array, or if before or later in their lives it was just a tube that ran further up the hull and got reeled inside like a ballast tank or something, I have another aluminum rod I can run up the hull if that's the case. I'm also thinking I'll probably 3d print the extra bumps and pods on deck, but I can't find any plans that show them or a definitive explanation of what they are.

[Tom Dougherty]

Yes, the Skipjacks were refitted with 7 blade J screws. See photo in dry dock, below

[Vepr157]

The box had a hinged cover that exposed a set of rollers so that the array could be fed down through the tube. The array was stored wrapped around a set of portable stanchions on the diesel exhaust spine. I presume the tube that runs forward from the box is for the cable and the winch/drum is somewhere in a ballast tank. I'm not sure what the little dome aft is for, although it definitely wasn't PUFFs. Perhaps it was a later form of GNATS, which you will more commonly see as a football-shaped fairing on a short strut.

Jacob

[razgrizbsg27]

Ok, thank you very much! And is GNATS the thing that was mounted on USS Cavalla's bow? Cause its shaped exactly like what you described.

[Vepr157]

Ok, thank you very much! And is GNATS the thing that was mounted on USS Cavalla's bow? Cause its shaped exactly like what you described.

GNATS looked like this:



The "wart" on the bow of the Cavalla (and Sturgeon and apparently one 594) was a fairing over the mechanically-steered, high-frequency component of the BQH-4 sonar array. The other outboard component was a thick-line towed array, the predecessor to the TB-16.

Jacob

[Tom Dougherty]

And is GNATs the thing that was mounted on USS Cavallas�s bow?

Do you mean the large installation on Cavalla, as pictured here:
https://www.pinterest.com/pin/334673816031009573/
https://www.history.navy.mil/bin/imageD ... .1280.jpeg

I know someone who was aboard when this was on bow. I�m not exactly sure of the function. It was only there for a limited period.

[razgrizbsg27]

Yes exactly, I never knew what that was, I just guessed it might have been GNATs based on the description of it.

[Woodstock74]

Can someone who has the Moebius 1/72 Skipjack kit reach out to me (direct message me), I need a dimension.

[Tracy White]

PM out.

[seaforce]

Near end phase of building, an 1/228 Monogram SSN Skipjack, next step is to base coat and paint.

The equiptment-systems on top of the sail not glued down yet, not decided what systems to keep in the deployed mode, I dont like the cluttered look.

not sure of the dates the model represents, I added fwd sonar intercept reciever, aft active sonar jammer, and towed array, the seven bladed propeller, guessing this would be late 1970s or early-mid 1980s, base on photos from online.

[Tom Dougherty]

Nice work on updating the much older Aurora/Monogram Skipjack kit! That is the one with the �reactor hatch� which is one of those 1960�s features back when we all had only tube glue and Testor�s paints. The late Ken Hart did major �plastic surgery� to correct some of the subtle errors of that kit. I still have that, along with his drawings.

Curious as to why you didn�t start with the later Mikromir kit. More accurate although the instructions have a major error in the rudder placement. The rudders trailing edge should match the trailing edge of the stern planes; not the leading edges.

As to your question about the propeller. The original �speed prop� was on both the Skipjack, George Washington SSBN class and even for a sh time on Thresher. The broad, fan blade shape interacted abruptly with the wake of the rudders and stern planes. This resulted in the blades vibrating, giving off low frequency blade rate noise. Low frequency noise Carrie�s for great distances in the deep sound channel. It has been reported that SOSUS hydrophones (which were positioned in the deep sound channel) tracked the Washington SSBN with her original propeller all the way across the Atlantic on her initial patrol.

Bottom line is the 5 blade speed props were replaced in the early 1960�s with the 7 blade skew back propellers. The skew back gradually entered and exited the disturbed wake area. That and other features led to a significant decrease in blade rate noise. So, my best advice is that an �as built� Skipjack would have the 5 blade speed propeller, but one with the early towed array is 99.9% certain to have the 7 blade skew back version. I would recommend Mike Fullers (Mulsanne Mike) 3-D 1/144 as the closest match for your kit.

[seaforce]

Thanks Tom Dougherty for the info; I picked up this monogram model of the skipjack few years ago, just decided now to build it, after glueing the two piece hull and the sail together, I was looking at it , said this thing needs some more work, after looking online mostly images, and the 1/72 scale moebius Skipjack photos online, plus, I have a copy of Norman Friedman's U.S Submarines since 1945, I decided to scratch build all the modifications.

[seaforce]

Finally painted the skipjack, ended up painting the hull: gunship gray, upper hull deck and sail is mixed of oily black and black, lower hull is hull red, decided to add the 585 number to sail (I know the USN left the numbers off sometime during late 1960s, I wanted something on the model as to show what boat this is). kind of flipped the color pattern that appear on the box top, left edge, which show hull and lower hull all black with light gray upper deck and sail.

[Tom Dougherty]

I hate to be the bearer of bad news, but the propeller should turn clockwise (as viewed from the rear) rather than counterclockwise. A better propeller might be one of Mike Fuller's 3-D printed propellers. These are not exactly the right scale (1/144) significantly oversized vs. the odd 1/228 (or so) Monogram kit. Possibly he might resize one if you contact him.

[seaforce]

Thanks Tom Dougherty for your input :That was my first attempt to scratch build a propeller, the kit came with a three bladed propeller, I guess I have do better research and figured this out, and attempt another scratch build propeller. odd ball kit anyways, If I acquire any more Submarines it be in 1/350 scale, I might willing to buy aftermarket parts for it in 1/350 scale, I do have a revell 1/253 scale George Washington class still in the build stack, it came with a five bladed propeller so I keep that as is.