The Ship Model Forum

Ditto! Beautiful work on a Sub with some rather "exotic improvements".

I hope we will get some posts regarding the Scoops. The ISW rendering looks very cool. ( Pun intended)

Nino.

Nice job on a unique hull Tom!

USS [i]Narwhal[/i], SSN 671 prototype kit from Iron Shipwrights. The final kit will feature a resin hull and 3-D printed sail, planes, rudders, screw, and masts.

[b]Narwhal Background:[/b]

The Navy challenged Electric Boat to build a quieter submarine. A unique design under project SCB 245, Narwhal was her own class. Forward of the reactor compartment she was broadly similar to the contemporary Sturgeon-class submarines, but with a slightly larger diameter to accommodate the natural circulation reactor setup.
Electric Boat identified reduced sound signature improvements. The first was the main reactor coolant pumps. These large, high-pressure pumps spin under heavy load and can be the most significant acoustic source of any nuclear-powered submarine.

General Electric designed Narwhal’s unique S5G power plant with the reactor vessel situated low in the submarine’s hull and the two steam generators situated above the reactor, cocked slightly to fit into the hull. This arrangement facilitated a natural flow of the reactor’s primary coolant. This pressurized-water reactor (PWR) design heated its primary loop in the reactor and convection moved the water into the steam generator near the top of the loop where energy is exchanged into the secondary loop system to generate steam for propulsion. After heat transfer, the primary coolant flows back down towards the reactor vessel in a return loop.

Both initial low power conditions as well as when high power for maximum speed require the reactor coolant pumps. However, there is a wide region of power between these two conditions that allow the main engines and turbines to run normally without the main reactor coolant pumps working.

To address acoustic noise from the standard propulsion turbines which required a large reduction gear system to slow the propeller to usable, efficient turns, a revolutionary, direct-drive main engine turbine that was mechanically linked to the shaft was installed. This system operated at a lower RPM and was larger than the original reduction gear design, 12 feet in diameter and 30 feet in length, resulting in a slightly wider submarine than the Sturgeon class design, on which Narwhal was based.

The main seawater intake system is used to cool and condense the steam from the drive turbines. Two seawater scoops were added to the stern planes that would force water into the main seawater system as the Narwhal moved forward. During low speed, slow approach operations these scoops moved enough water to cool the condenser loads. Also, new ship service turbine generators which operated at a lower RPM (quieter).

In a subsequent overhaul, sonar was upgraded to the AN/BQQ-5D spherical bow array system along with a long line TB-23 towed array was added on the starboard side, with a deploy tube on the upper stern plane.

The natural circulation reactor design was incorporated into the Ohio SSBN S8G design, as well as the Seawolf class S6W and the Virginia S9G reactors. Other aspects, such as the direct drive turbine were not repeated in subsequent classes. Also, the condenser cooling scoops violated SubSafe principles by having long internal piping runs under sea pressure, so short direct runs with pumps were employed.

If you get a chance, post some photos of your Nautilus here. I would love to see it in 1/72! What new hulls are in progress? (Besides RBR, that is)

I just wrote a three part article for American Submariner magazine on the establishment of Raborn’s Special Projects office for Polaris. And that indeed was the first use of “Special Projects”. Most of the article (part 1 has published) concerns the challenges of building the Polaris system (submarine, missile navigation, guidance, etc.) employing mid-1950’s technology.

Special Projects is a broader term for sure, but Ocean Engineering, another term I have seen used is probably a bit more obscure, although for the kinds equipment and modifications carried out, more specific. Some under the NURO sponsorship .

Losing MINSY, as you have mentioned, was a big mistake. Now there is a shortage of Naval shipyards, and the expertise of Mare is long gone.

The term "Special Projects" is used pretty loosely. It was originally assigned to denote the Polaris program office under Raborn.

Any submarine can perform CNO-designated Special Projects. My first boat, a boomer was involved in one, and it was study performed by some scientists we had onboard for a few days.

Narwhal conducted many Special Projects due to her low acoustic signature. TB-29 testing was but one that has been acknowledged publicly. The array was much longer than a TB-16, and the pronounced hump on the stern likely housed the array and some of its handling equipment. It was assigned to an East coast DevRon.

The Ocean Engineering program was called CNO Special Projects on my transfer orders. I didn't have a clue as to what OE meant until after I checked in. All OE boats and other assigned assets on the West coast were assigned to COMSUBDEVGRUONE, based in San Diego. The MINSY platforms were assigned there because of the cleared shipyard work force and industrial and design capabilities MINSY offered. They pulled off some amazing feats that may someday be revealed.

Nautilus was a hit and I'm on the the next set of hulls.

CC, Very nice work on the sail! The idea for a Narwhal originated with you, since you pointed out that it was a "forgotten" Special Projects boat. I suggested it to the manufacturer based on your comments.

How did the 1/72 Nautilus project go?

[attachment=0]Parche_81_Sail_v5.jpg[/attachment][quote="Vepr157"]USS Richard B. Russell (SSN 687) was the fourth American special projects boat and she had a fairing aft of the sail for a towed communications buoy (it was called a bustle, as in "Russell's bustle"). Parche had a very similar fairing from the mid 1970s to the late 80s.[/quote]

1/72 Sail WIP

Model kit of Narwhal coming soon. Stay tuned.

Here is my 1/700 Narwhal, made out of a 1/700 HB Los Angeles, removed center section approx 20.9 mm, moved sail up and raised it, trimmed and moved fair water planes, still need to add towed array tube between fairing and stern plane, and a brass etch screw and paint.

[img]https://i.imgur.com/mfxixmL.jpeg[/img]

[img]https://i.imgur.com/BbdTOQ8.jpeg[/img]

[img]https://i.imgur.com/4UOOJVK.jpeg[/img]

[img]https://i.imgur.com/eWIXja7.jpeg[/img]

[img]https://i.imgur.com/j2SNTQm.jpeg[/img]

[img]https://i.imgur.com/TePmbuK.jpeg[/img]

[img]https://i.imgur.com/3l3IuMX.jpeg[/img]

[img]https://i.imgur.com/5sPx6S4.jpeg[/img]

[img]https://i.imgur.com/yYsxXoQ.jpeg[/img]

Awesome, thank you v much

The PUFFS fairings (end plates) are pretty much identical to those of a 637, and yes, the diameter of the hull is 33' just like a 688. The sail is about in the same position as a 637 and is nearly identical to that of a 637. The towed array fairing is on the starboard side and looks just like one on a 637. The scoops are just small oval holes in the leading edge of the stern stabilizers. Another little detail is that her propeller had a diameter of 12'6" in diameter instead of 15' like a 637.

Jacob

So to check, Narwhal is the width of a 688, a bit longer than a long hull sturgeon, towed array fairing on the port side, sail a further aft than on Sturgeons, and she does have the sturgeon type end plates on her stern planes? in addition to the scoops of course.

I'm checking cause my plan to build a 1/700 USS Narwhal is to get a hobbyboss Los Angeles class, with the incorrect stern planes that have the end plates, chop a section out of her middle to shorten her the right length, fill the recess for the sail and move it to the right place, plus some plasticard elements to enlarge it, then some thin brass for the towed array tube to run from the fairing to the end plate on the port side, and I'll probably notch or drill small ports In the stern plane fins for the seawater intakes, since no one has found actual dry dock pictures, that's our current best guess.

Does that sounds like a solid plan for a 1/700 Narwhal?

[quote="Timmy C"]Pintrest links don't always play well (I get a 404 error with the one you posted), so I believe this is the page it was referencing: http://www.usmilitaryart.com/submarines.htm

There, it cites the following right after the text you posted:[quote] Much of the information used to accurately portray NARWHAL is this profile drawing by George Bieda came from a member of her commissioning crew (a Plank Owner).[/quote]
Whether that refers to just the drawing or also the text description, though...[/quote]

After reading the statements about the reactor plant (which is nonsense) "...natural circulation not pressurized" S5G was a PWR, which means pressurized water reactor. There are coolant pumps but like the later S8G core they were used to start circulation and then only for High Power operation. While i was never at Idaho Falls, I was at KAPL and was EEOW and Engineer qualified on S5W (S3G core three) and S8G submarines along with the MARF (S7G) prototype, MARF was the "Rodless Wonder" in it didn't have control rods and was one of Hymies pet projects. I interviewed with him prior to my Naval Career, he was to say the least different. I can't really believe the linked post which shows a lack of knowledge by the person who set up that site. If one this is definitely wrong everything else is also suspect.

I might be going crazy, but if I squint my eyes, it looks like the [i]Lipscomb[/i] has a dark oval on the leading edge of her stabilizer:

[url]https://i.imgur.com/A1po5Ow.jpg[/url]

Could this be a seawater inlet? I have never heard any references to the [i]Lipscomb[/i] or any other American submarine besides the [i]Narwhal[/i] having seawater intakes, and I believe that the [i]Lipscomb[/i] was identical to the other Sturgeons besides the power plant. It might be that the [i]Lipscomb[/i]'s design was begun after the SUBSAFE regulations and she wasn't able to have them, but it's possible her design originates from before big seawater intakes were outlawed. Unfortunately, I have no other photographs or plans of the [i]Lipscomb[/i] to investigate further.

Jacob

Thanks, Tim for the link correction. Looking closely at the drawing, I can see the inlet on the horizontal stern plane.

Pintrest links don't always play well (I get a 404 error with the one you posted), so I believe this is the page it was referencing: http://www.usmilitaryart.com/submarines.htm

There, it cites the following right after the text you posted:[quote] Much of the information used to accurately portray NARWHAL is this profile drawing by George Bieda came from a member of her commissioning crew (a Plank Owner).[/quote]
Whether that refers to just the drawing or also the text description, though...

Found this little write up online:
[quote][i]USS Narwhal SSN 671 was a very unique submarine. Although built as part of the Sturgeon Class in the late 1960s, very little of the NARWHAL’s design was based on the design of other boats in that class of nuclear-powered attack submarine. Her propulsion plant was one of her unique features. It was based on the ability to scoop seawater in through inlets on the rear stabilizer fins, and use this as coolant for the natural circulation (rather than pressurized) reactor plant. This, along with the small reactor coolant pumps, and a directly coupled turbine, made her the quietest submarine of the era.[/i] [/quote]

How authoritative is that description of the scoops? I have no idea. I know the direct turbine drive is correct. Scoops on the stabilizer fins would make for a long piping run internally, with the pipes under sea pressure. No wonder SubSafe ruled out any followup builds with that design.

Here's the site URL: [url]https://www.pinterest.com/offsite/?token=246-75&url=http%3A%2F%2Fwww.usmilitaryart.com%2Fsubmarines.htm&pin=6755468165952242&client_tracking_params=CwABAAAADDY4MDE3ODY1NjQ1NwA~0[/url]

Does anyone have a photo of the Narwhal's aft planes?

I read that the Narwhal's seawater scoops might have been part of her aft planes, as on the British Swiftsure, Trafalgar, and Astute-class submarines. This would make sense given that the British also told the US Navy about rafting.

Jacob

USS Richard B. Russell (SSN 687) was the fourth American special projects boat and she had a fairing aft of the sail for a towed communications buoy (it was called a bustle, as in "Russell's bustle"). Parche had a very similar fairing from the mid 1970s to the late 80s.

There was another Sturgeon that had a small superstructure behind the sail but i cant remember off the top of my head. Nice fact about the fairwater planes. I suppose it would make sense since they would need to be bigger with the hull not tapering in below them like a standard sturgeon.