Calling all Sturgeon-class (SSN-637) fans

Grandahi · Post by **Grandahi** » Mon Jul 26, 2021 12:10 pm

Tom Dougherty wrote: As I mentioned above, it is the 1966 �as built� USS Sturgeon in the kit. In order to do a late model, you will need to lengthen the hull, add a dome aft (I believe this is the WLR-9A) and a towed array hull fairing, tube, tube support structure and deployment tube on the port side. I have never seen a vortex attenuators hub on a 637 class screw.

As far as lengthening the MikroMir 1/144 Sturgeon hull, it is about 1/8 inch thick glass reinforced resin (GRP), not polystyrene. Not impossible, but a tougher job to lengthen than if it were polystyrene.

My bad, when I said �late model� I really meant late period, i.e. �90s 637s, but didn�t realize it until it was 1am and I was on a train in the middle of nowhere and no way to edit the post.
As for doing a stretch, nope, most I will do is add the necessaries like towed array, etc. The 1/350 can represent my stretch.

As for attenuators (we called it �the device� cuz hush-hush at the time), we had them on Aspro and Tunny, probably on the other boats too but I can only vouch for those two. A semi-interesting story about Aspro�s device, during availability when the torpedo-damaged screw was replaced (a story for another time and place, perhaps), shipyard lost it! It was going to be a big deal with NIS coming down with charges of sabotage, etc, and putting out to sea with a dunce cap instead. We had to get a talk about it since technically it was our equipment (Machinery division), but hey we didn�t take it offf, ask the crane operators! Anyway it turned up somewhere and all was right with the world once more.

Scott

Vepr157 · Post by **Vepr157** » Mon Jul 26, 2021 1:56 pm

Grandahi wrote: As for attenuators (we called it �the device� cuz hush-hush at the time), we had them on Aspro and Tunny, probably on the other boats too but I can only vouch for those two. A semi-interesting story about Aspro�s device, during availability when the torpedo-damaged screw was replaced (a story for another time and place, perhaps), shipyard lost it! It was going to be a big deal with NIS coming down with charges of sabotage, etc, and putting out to sea with a dunce cap instead. We had to get a talk about it since technically it was our equipment (Machinery division), but hey we didn�t take it offf, ask the crane operators! Anyway it turned up somewhere and all was right with the world once more.

Scott

Was that similar to the hub vortex diffuser on the 688s (a boss with a number of blades), or the propeller boss with a straight taper (see drawing)?

Jacob

Grandahi · Post by **Grandahi** » Mon Jul 26, 2021 2:40 pm

Vepr157 wrote:

Was that similar to the hub vortex diffuser on the 688s (a boss with a number of blades), or the propeller boss with a straight taper (see drawing)?

Jacob

We had 11 blades on the device, (a question I asked of the nubs when they came for a propulsion train checkout), similar to what the internet shows on the 688s. As far as any other details, I didn't have a tape measure or a protractor with me, alas, so I am useless for providing any other details. The straight taper was the dunce cap we were going to be saddled with otherwise, if I am interpreting your question/drawing correctly.
Scott

Vepr157 · Post by **Vepr157** » Mon Jul 26, 2021 5:02 pm

Great, thanks for the info! The 688 one has 11 blades as well. Funnily enough you can look its naval stock no. up online:

https://www.parttarget.com/2010-00-106- ... B35ACCC521

One thing that's always mystified me is why the 585s and 637s had that unusual straight-taper boss, but the 594s had a regular conical boss.

Jacob

Woodstock74 · Post by **Woodstock74** » Mon Jul 26, 2021 9:11 pm

Grandahi wrote:
Vepr157 wrote:

Was that similar to the hub vortex diffuser on the 688s (a boss with a number of blades), or the propeller boss with a straight taper (see drawing)?

Jacob
We had 11 blades on the device, (a question I asked of the nubs when they came for a propulsion train checkout), similar to what the internet shows on the 688s. As far as any other details, I didn't have a tape measure or a protractor with me, alas, so I am useless for providing any other details. The straight taper was the dunce cap we were going to be saddled with otherwise, if I am interpreting your question/drawing correctly.
Scott

Well this is extraordinarily interesting!

Woodstock74 · Post by **Woodstock74** » Mon Jul 26, 2021 9:19 pm

This isn't going to get me a visit from the goon squad is it?

Tom Dougherty · Post by **Tom Dougherty** » Tue Jul 27, 2021 7:07 am

That�s an interesting factoid! I have never seen a J screw with the 11 blade attenuator on it. How widespread was it employed? What time era (1990�s?) was the attenuator added to the 637�s? Any idea on the effectiveness?

My understanding is it was a response to the Russian installation of the SOKS wake detection system. The attenuator seemed to come and go in a short period. I was never clear on whether the 688I ring screw was to control tip vortices or to protect the prop tips under ice. Or both.

Build Report on the 1/144 Sturgeon
As far as the MikroMir Sturgeon kit, I joined the two halves of the bow cap. I ran small amounts of microweld along the interior of the cap to join the pieces. Unfortunately, although the two pieces are close matches, but you end up with a slight, �overbite� lip at the very front. So, out came the 400, 600 & 1000 wet sand paper to make the two pieces meet smoothly. I was very careful to frequently change sanding directions so as not to end up with a flat spot. I also had to use Tamiya putty to hide the seam. I placed tape very close on either side of the seam to limit the putty spread. So that simple process took two hours to get to a decent result.

Tom Dougherty · Post by **Tom Dougherty** » Tue Jul 27, 2021 11:05 am

Woodstock74 wrote:This isn't going to get me a visit from the goon squad is it?

Jethro Gibbs is on his way!

CC Clarke · Post by **CC Clarke** » Wed Jul 28, 2021 5:24 am

The Los Angeles made their homeport in Pearl in '78. Soon after their arrival, I attended a class with the lead sonarman who gave us a tour of the boat. I remember him mentioning they had an 18-bladed screw - a standard 7 blade model with an 11-bladed vortex dissipater, so it was installed very early on. He said they experimented with a five-bladed screw and while the speed was significantly greater, it was a lot noisier, so the 18 bladed screw was adopted.

Compared to the 637's on the waterfront, the LA was like the starship Enterprise.

Nino · Post by **Nino** » Wed Jul 28, 2021 12:12 pm

Folks, I am on the "slightly uninformed" list as to propellers.

Are these examples of the "stuff" being talked about?
( Top Pic a Type 212 prop)
( Middle Pic: 3D printing. Thank You Mike.)
(Bottom pic a 688 class prop example)

Nino.

P.S. Top photo I will attribute to J Gibbs. (Ya know, In case)

And take a look here if building 1/350 Subs: http://www.steelnavy.net/FullerPropelle ... herty.html

Grandahi · Post by **Grandahi** » Wed Jul 28, 2021 2:08 pm

Tom Dougherty wrote:That�s an interesting factoid! I have never seen a J screw with the 11 blade attenuator on it. How widespread was it employed? What time era (1990�s?) was the attenuator added to the 637�s? Any idea on the effectiveness?

My understanding is it was a response to the Russian installation of the SOKS wake detection system. The attenuator seemed to come and go in a short period. I was never clear on whether the 688I ring screw was to control tip vortices or to protect the prop tips under ice. Or both.

Unfortunately I cannot comment on how widespread the employment was, only physically seeing it on two different boats, Aspro and Tunny. I was on board and decommissioned Aspro from 1992-1995, and Tunny from '95-'96. This was in Pearl Harbor btw. Other boats that were there at the time besides the usual 637s and 688s, were USS Kamehameha (SSBN/SSN-642), undergoing conversion to SSN (and the reason we never carried the DDS on Tunny during my time on her), and USS Haddock (SSN-621), which came to Pearl for inactivation and decommissioning. Fun factoid, ex-USS Aspro and ex-USS Haddock were towed together in 1995 back to Washington for recycling.
I always figured the device was installed as part of Aspro's overhaul at Mare Island ca. 1989-90, which I believe is when she got SHT, sonar and fire control upgrades, etc. With those upgrades we could do all and more than 688s, except go as fast.
For the most part we were too busy keeping her (Aspro) in a state of readiness to really delve into when which equipment got put on. Tunny was in MUCH better shape, even for being just a few years younger . . .

Grandahi · Post by **Grandahi** » Wed Jul 28, 2021 4:48 pm

Woodstock Mike had a mockup of an example, looks like the post has since been deleted. Anyway I was unable to chime in at the time, but it looked like reality to me. Although I think it should have more pitch on the attenuator blades, as in the upper left of the attached pic. But otherwise who is going to rivet-count it?
We had the tech manual with profile and pitch drawings for the screw, and it indicated it was the same on a slew of different classes of boats, as we all know now. Of course the 688s had a bigger and newer design, to account for their larger power-plant. No books on the device.
Cheers.

Woodstock74 · Post by **Woodstock74** » Wed Jul 28, 2021 7:34 pm

Based on Grandahi's description:

Grandahi · Post by **Grandahi** » Thu Jul 29, 2021 6:33 pm

Woodstock74 wrote:Based on Grandahi's description:

Screenshot 2021-07-28 193909 Sturgeon_w_the_device.jpg

Screenshot 2021-07-28 193834 Sturgeon_w_the_device.jpg

Looks as good as anything out there! Two thumbs up.

Woodstock74 · Post by **Woodstock74** » Fri Jul 30, 2021 2:39 pm

Wish we had some photo evidence. There are precious few images of Sturgeon screws. And zero of this.

Grandahi · Post by **Grandahi** » Fri Jul 30, 2021 5:41 pm

Woodstock74 wrote:Wish we had some photo evidence. There are precious few images of Sturgeon screws. And zero of this.

Agreed! But in the meantime here are some pics that you may or may not have already, they are handy for seeing the variable pitch (twist) if nothing else .

Woodstock74 · Post by **Woodstock74** » Mon Aug 02, 2021 6:38 pm

Grandahi wrote:
Tom Dougherty wrote:That�s an interesting factoid! I have never seen a J screw with the 11 blade attenuator on it. How widespread was it employed? What time era (1990�s?) was the attenuator added to the 637�s? Any idea on the effectiveness?

My understanding is it was a response to the Russian installation of the SOKS wake detection system. The attenuator seemed to come and go in a short period. I was never clear on whether the 688I ring screw was to control tip vortices or to protect the prop tips under ice. Or both.

Unfortunately I cannot comment on how widespread the employment was, only physically seeing it on two different boats, Aspro and Tunny. I was on board and decommissioned Aspro from 1992-1995, and Tunny from '95-'96. This was in Pearl Harbor btw. Other boats that were there at the time besides the usual 637s and 688s, were USS Kamehameha (SSBN/SSN-642), undergoing conversion to SSN (and the reason we never carried the DDS on Tunny during my time on her), and USS Haddock (SSN-621), which came to Pearl for inactivation and decommissioning. Fun factoid, ex-USS Aspro and ex-USS Haddock were towed together in 1995 back to Washington for recycling.
I always figured the device was installed as part of Aspro's overhaul at Mare Island ca. 1989-90, which I believe is when she got SHT, sonar and fire control upgrades, etc. With those upgrades we could do all and more than 688s, except go as fast.
For the most part we were too busy keeping her (Aspro) in a state of readiness to really delve into when which equipment got put on. Tunny was in MUCH better shape, even for being just a few years younger . . .

Just to clarify, you only saw this screw on those two boats (Aspro and Tunny)?

Grandahi · Post by **Grandahi** » Thu Aug 05, 2021 11:40 am

Woodstock74 wrote:
Just to clarify, you only saw this screw on those two boats (Aspro and Tunny)?

That is correct good sir.

CC Clarke · Post by **CC Clarke** » Sun Nov 03, 2024 12:36 pm

Last batch of a half-dozen resin-printed 1/72 18-bladers. Installed on one on my favorite Sturgeon class boats, destined for one of two museums. (I'll build another one when I clear out my current workload . . . measured in years . . .)

CC Clarke · Post by **CC Clarke** » Sun Apr 06, 2025 9:27 am

This section of the forum has been far too quiet lately!

Parche is complete, with the exception of a five-foot acrylic cover for the base. I'll save up and have one custom-built prior to shipping it to its new home in the Fall. I have two other hulls to complete for a Seawolf reunion in Vegas and have made getting those knocked out in 1/144 scale the highest priority since they print faster and several can fit in my car.

Attached are a few P-boat renders with a shot of the final product displayed at a recent USSVI event. The hand you see covering the screw is attached to the admiral who was our guest speaker.

There are 90 keel blocks with pads on the mating surface to protect the exterior paint. Each block has it's ID number stamped on the bottom. I'll remove the hull once more for weathering prior to shipping it out.

CC