Calling all Russian submarine fans

[Neptune]

Perhaps better for the fin type sensor:


On Gepard, the last Akula, the fin appears to be slightly more centred towards the conning tower, while it also seems to stand upright. on the others it's slightly angled outboard.

[Tom Dougherty]

Thanks, Neptune! Great photos.

There is a "device" on the 688 class (which I have never seen represented on a model) that is almost certainly a countermeasure for these wake detection systems. I inadvertantly got to see this "device" several years ago. It took some additional time for me to put 2 and 2 together....

[Patman]

I�ve downloaded these images from a French website, that shows a Brit Trafalgar class SSN with something that clearly looks like a ripoff SOKS system. I have no clue into how did they get it, but everyone here knows about the British intelligence service reputation.

Saludos

[Neptune]

The Traf looks in a rather deplorable state... Never seen that test though, pretty funny.

As for how it works, I'm not sure. I always sort of thought it would detect the higher water temperatures from cooling water outlets.
Never quite thought about pressure differences. The issue is this, considering the very close position of these sensors (around the hull and sail), they'd have to be EXTREMELY directionally sensitive at any relatively long range, otherwise your triangulation will be crap.
The other solution to this is that it would only work at very short ranges, giving you bigger angle differences again.
I always thought they'd get closer on sonar and then switch to SOKS to trail a sub at close range, although it wouldn't make much sense, as passive sonar isn't making any noise itself.

All the above is just speculation though.
To get back to the Victor, there is a possibility that the fin on the sail, without any drop shaped sensors on the deck, could also mean that on the bottom it has just a fin type sensor as well, . Like half of the Akula system.

The test of the whole system was in fact performed on a converted Victor-I, the K-147. She had the later Victor III sail, with the big and small fin. On the lower hull she appears to have had a fin on each side. On the top hull she had one drop shaped antenna on starboard and two on port ( the latter two just next to each other). On the bottom there appears to be no sign of any drop shaped sensors.
All in all it's a big mystery, what is the function of each sensor and why all the different configurations? In any case, if you want a proper model of a Russian sub, there is a lot of things to pay attention to!

[Patman]

Hi Neptune

I�m sorry, but my understanding of French is poor, so I had to use the crude Gooogle translator. The French site where I got these pictures, when describing the SOKS system, said the system detects several factors beyond density and salinity, it also detects residual redioactivity in the water caused when this water goes through the reactor cooling system, leaving that trace on the wake of the nuclear sub that can be traced hundreds of miles.
This is the link to that forum:
http://www.air-defense.net/forum/index. ... =10890.180

Saludos

P

[Tom Dougherty]

it also detects residual redioactivity in the water caused when this water goes through the reactor cooling system, leaving that trace on the wake of the nuclear sub that can be traced hundreds of miles.

Despite the link (it's on the internet, it must be true!) that seems rather unlikely to me. The reactor water in the primary loop that passes through the reactor is recirculated and never vented overboard. It is highly purified water and passes through a resin to remove impurities, so you wouldn't want to dump it (besides teh fact it is radioactive). In the reactor heat exchanger loop, the primary reactor water (which is radioactive) heats the secondary steam propulsion water, but the two never mix. Hence the secondary loop is not radioactive. If it were, it would be a problem in the engineering spaces. To cool the secondary (steam) loop, seawater is run through the condensers, but those are tubes within tubes, again with no mixing of the cooling seawater and the secondary steam loop water. In this case you don't want the corrosive chlorides mixing with your secondary steam loop water. Hot chlorides are not kind to metals that the steam loop is constructed from. So, 1.) the secondary (steam) loop is not radioactive and also 2.) under normal circumstances, it never mixes with the condensor steamwater. The seawater that cools the steam condenser is continually brought in and then vented overboard and is warmer than the surrounding seawater, but not "hot" as in radioactive.

With virtually no radioactive material going overboard, it would be hard to trace a submarine for hundreds of miles.

[Neptune]

That's at least one option less then.
The mentioning of the bubbles might be one of the functions of one of the sensors, perhaps the drop shaped ones.
The reason I was thinking in that direction is that the Russians are quite known for their wake-homing "fat" torpedoes. These are actually following a wake's bubble path as well. They cross it and when they leave the bubble zone, they turn at a set amount of degrees back, like this they zig-zag their way to the target. From which range they can actually detect those bubbles I don't know.

Thought I'd drop in a couple more. While I was thinking about it, the Chakra (Ex-Nerpa) was in fact completed to a basic Akula I version, except perhaps the slightly lengthened hull and sail, but in outfit she's pretty close to the Kashalot and Delfin. A second group has the 6 extra torp tubes (I think "Volk" is one of these), the third group has SOKS and extra torp tubes with sometimes a lengthened sail.
Some of the fully equipped ones are Samara, Kuzbass, Pantera. The last ones Tigr and Vepr appear to be slightly longer and have the longer sail, they "could" be named the Akula II class. Gepard is again totally different and would be an Akula III.
Here are some pics of Nerpa/Chakra:




And here Kuzbass and Samara:




And the Gepard (which was dry docked not too long ago with prop and shaft removal etc.)






Talking about Chakra, anybody know of any Charlie (I and II) class plans or material? It appears to be a ghost ship. Lots of crap written about them, but very little real source material to be found. Most plans and drawings still depict them with twin props while I know for sure (from the little stuff that is available) she had a single prop... Up till now very few pics available and nothing really credible on plans.

[Patman]

it also detects residual redioactivity in the water caused when this water goes through the reactor cooling system, leaving that trace on the wake of the nuclear sub that can be traced hundreds of miles.

Despite the link (it's on the internet, it must be true!) that seems rather unlikely to me. The reactor water in the primary loop that passes through the reactor is recirculated and never vented overboard. It is highly purified water and passes through a resin to remove impurities, so you wouldn't want to dump it (besides teh fact it is radioactive). In the reactor heat exchanger loop, the primary reactor water (which is radioactive) heats the secondary steam propulsion water, but the two never mix. Hence the secondary loop is not radioactive. If it were, it would be a problem in the engineering spaces. To cool the secondary (steam) loop, seawater is run through the condensers, but those are tubes within tubes, again with no mixing of the cooling seawater and the secondary steam loop water. In this case you don't want the corrosive chlorides mixing with your secondary steam loop water. Hot chlorides are not kind to metals that the steam loop is constructed from. So, 1.) the secondary (steam) loop is not radioactive and also 2.) under normal circumstances, it never mixes with the condensor steamwater. The seawater that cools the steam condenser is continually brought in and then vented overboard and is warmer than the surrounding seawater, but not "hot" as in radioactive.

With virtually no radioactive material going overboard, it would be hard to trace a submarine for hundreds of miles.

Tom; I�ve just mentioned what the french forum posted. It doesn�t mean I buy everything internet says. But besides that, your further explanation clarifies the issue throughly. Thank you for that.

Saludos

P

[peppe]

neptune, i have some drawings and foto of charlies send pm your email so i can send you (are too big for the forum) the images
in the last book of apalkov on russian submarines (vol 2) it is a chapter on the two charlies
in the review taifun #25 6/2000 it is an article on the class with plans and fotos
ciao peppe

[Tom Dougherty]

Tom; I�ve just mentioned what the french forum posted. It doesn�t mean I buy everything internet says.

Didn't think you had necessarily believed it; I knew it was a repost.

My understanding is that the disturbance coming off of submarine propellers leaves a detectable underwater wake for some distance. In fact, there are some reports (See: Polmar & Moore's Cold War Submarines: The Design and Construction of US and Soviet Submarines) that the wakes can be detected by millimeter wave synthetic aperture radar from space, by the very tiny disturbances caused by the wake at the water surface.

"The Seasat satellite launched in 1978 effectively imaged ocean surface features such as internal waves and ship wakes using SAR20. Subsequent reports claim that Russian scientists have demonstrated a way of detecting submerged submarines using microwaves reflected from internal wave generated surface effects. These claims were further investigated in July 1992 by an unclassified joint US/Russian experiment which clearly detected waves beneath the surface, although no submarines were used in the experiment. The experiment made use of, among other things, SAR imagery from the ERS-1 satellite which was complimented by in situ and other remotely sensed data." Australian Defence Force Journal NO. 127 NOVEMBER/DECEMBER 1997.

I think the equipment on the Russian submarines can detect some of the disturbances left by a submarine moving through the water. Polmar mentions in his book an incident in the early 1990s where a 688 class was trailed by a Russian SSN using equipment that was non-acoustic and novel. I believe that since that time, certain equipment has been added to US submarines that mitigates in part the waves generated by the propeller. I have not seen it on any submarine scale models to date, but I have seen grainy photos of an unusual "object" on a 688 stern.

[Patman]

Thanks for your insights Tom

Didn�t know about how far millimeter wave technology can go.
Were the soviet navy the first to deploy something like the SOKS?
It seems the Royal Navy at least tried a similar array of sensors but only recently and on the HMS Trafalgar.
We�ll never know if they did follow the russian approach, something of their own, or abandon de idea completely.
I keep thinking around this issue, not because of the visibility of the antennas on my model, but also because I�m tring to figure out how this could be modeled in a wargame or simulation.
Probably you have already seen this upcoming game / tactical sim:

http://www.warfaresims.com/forum/viewforum.php?f=50

Saludos

P

[Tom Dougherty]

Probably you have already seen this upcoming game / tactical sim:

No, I'm afraid I don't really follow simulation games.
I leave that to my son, who actually devises military sim games with Larry Bond & is a co-founder of Shenadoah Studios:
http://boardgamegeek.com/boardgame/7648 ... -incursion
and: http://www.shenandoah-studio.com/art-di ... ing-bulge/

[RTBS]

Loooong time lurker. Not sure if this is the right place or not, and apologies if the answer is easily found somewhere on the forum. I did a search and didn't come up with what I was looking for. Anyway...

I'm looking for aftermarket Russian Submarine Decals. I figured a google search would give me a plethora of choices and yet I'm finding little to nothing. I'm guessing some of the sponsors might sell them, but I honestly don't have time to visit them all and see. Any of you fine folks have an suggestions? Primarily looking for 1/700 and 1/350th.

Thanks.

[Neptune]

Sure is the right place to ask you question.
I don't know of any real aftermarket for this kind of decals though. In 1/700 there are the Hobby Boss kits, they don't really cost much, so I guess, depending on class, that you could either use those decals or build the kit and apply the decals on the kit.
It all depends on class and scale.

Regarding our SOKS "research", I've found the Sierra class to have the SOKS mounted in, once again in different fin composition. The drop shaped sensors are present as well, but they seem to either retract, or stay in a partly "submerged" position in the hull. Pictures will follow soon.

For Peppe,
The real reason I'm looking for actual dry dock pics of that class is that something is absolutely missing on all drawings that I've seen for now. All Russian nuclear subs have scoops for the cooling water, no scoop is shown on any Charlie drawing... They also seem to indicate a creeper arrangement like the Kilo class, which would somehow surprise me for a class of this size (although I don't deem it entirely impossible either).

And some more pics for Tom. The Akula shown in these pics appears to be the Samara. The bow material doesn't appear to be metal as you can see it's somehow laminated. Not sure if the inside of the bow is normally filled with water, it would seem to be, considering the condition of the inside compartment (barnacles seem to be present).


Better view of the SOKS lower hull arrangement.

[subvariant]

And some more pics for Tom. The Akula shown in these pics appears to be the Samara. The bow material doesn't appear to be metal as you can see it's somehow laminated. Not sure if the inside of the bow is normally filled with water, it would seem to be, considering the condition of the inside compartment (barnacles seem to be present).

The bow would not be made of metal, since you are looking at the submarine's sonar system. Yes, this section would have been filled with water as well.

[Patman]

Am I crazy or the sonar dome is made of laminated plywood?
Is plywood a good sound permeable material? (Despite the predominance of GRP, ply is still used in yacht construction.)
Remember how good the Russians were making thousands of plywood aircraft during WW2.

[subvariant]

It does look like plywood, doesn't it? This area would see no differential pressure, so maybe it is possible.

[Tom Dougherty]

I believe it is GRP or some other similar plastic. As mentioned the area is flooded to permit sound coupling to the hydrophones, so it doesn't have to be as strong as the hull. The original Permit class US subs did have a steel bow cap, but the plastic caps are much better at sound tranduction. I'm not sure if marine plywood would have the same strength as some of the laminated plastics.

I am not seeing the barnacles mantioned in the pictures. I do see the extension from which th hydrophone sphere is hung, and some of the sound deadening material on the forward bulkhead to help isolate the bow sonar from the sub's own noise.

This looks to be some sort of accidental bumping. The entire bow cap is removable, and if the sonar transducers need work, the entire cap would be removed.

[Neptune]

Hi Tom (and others),

Agreed, I must say I was thinking the same at first. It looks a lot like wood, considering the edges of the "cut". But I guess wood would really rot away and/or deteriorate too fast to be used in this kind of appliances, even with a cover of some different material.
I kind of expected something like a different type of steel, but didn't quite think of something as vulnerable as GRP to be used. I wonder now if that side area, which is supposed to contain a side looking sonar is made of the same material. I guess so, since it's also strongly marked to avoid any tug contact there. On the other side it does raise some questions on the overal construction of these boats, I assume that sonar would be outside of the pressure hull mounted in between the hulls in this case?
Another thing to see on the above pics is that her creeper props are also extended, seen more often than the diving planes, but still a special sight.

Here is a series of the Victor III, including a close-up of the fin mounted on the sail.
A sight of the Vic III stripped of most of the tiling, you can clearly see how thick it is and also the upstanding edges around the ballast vent arrangement.




Always expected that those diving planes were "both in - both out", didn't quite think of them being seperately controllable. Perhaps a defect since the sub later on entered port with a partially extended plane as can be seen in next pics.










Considering the above pics and what you have Patricio, what is the overall accuracy of the Hobby Boss kit you have? Is it any good?

Looking at the fin of the Victor III, which contains different sensors from the Akula's, I think the top part of the fin, with the rounded cap, would be the same sensor as the drop shapes which are separate on Akula and Sierra. I'm looking at the Mike class for now as well, and that ship has fins on the back, I'm not sure weather it is SOKS or some sort of stabilisers, the fins don't seem to have anything sticking out of them, so I guess they are there for stabilisation. Anybody have good pics on that?

[Patman]

As I mentioned in a previous post, Hobby Boss kit captures very well the shape and proportions. I haven�t checked how dimensionally accurate is compared to plans and measures.
Detailwise the kit captures most notable panel lines well, including the grills on the sides of the sail. The kit brings the SOKS sensors mounted on each side of the cockpit, but don�t expect to differentiate the shapes of the probes, that part is vey tiny at 1/350.
The kit is somewhat lacking in decals. Some hatch markings, hull numbers, post Soviet era badges, etc. I�m surprised that no one is providing custom decals of postwar Russian subs given the increasing diversity on the subject.
It also comes with two potoetched two blade creep propellors, but no axis and hub are provided (they should be very small and I have no clue into how to simulate them at that scale)
The 4 bar RDF retractable antenna is an awfully tiny PE part that needs extra careful manipulation. getting the two rectangular pieces glued together using bare eyes is painful. Fortunately I�ve got those magnifying glasses with a led light.

I�ll post some update pictures of the sail details soon.

Saludos

P