Military Forum for Russian and Global Defence Issues


    Pump jet propulsion system in russian submarines

    jhelb
    jhelb

    Posts : 618
    Points : 715
    Join date : 2015-04-04
    Location : Previously: Belarus Currently: A Small Island No One Cares About

    Pump jet propulsion system in russian submarines Empty Pump jet propulsion system in russian submarines

    Post  jhelb on Mon Jun 06, 2016 9:07 pm

    George1 wrote:Sixth Varshavyanka-class sub for Black Sea Fleet launched in Petersburg

    Russia will build diesel-electric submarines for the Pacific Fleet, fifth-generation conventional submarines for the Northern and Baltic fleets

    George, since you keep track of all the latest development in the Russia, I had one question. A couple of yers ago there were several reports about  a lot of R & D & some mature technology demonstrations on propulsors done in Russia.

    Given the fact that  Pump-Jet Propulsor & MHD-based drives are the way of the future how soon can we see Russian subs with these features?  (France has already incorporated it in the Shortfin Barracuda that it is selling to Australia) Thanks.
    GunshipDemocracy
    GunshipDemocracy

    Posts : 4913
    Points : 4943
    Join date : 2015-05-17
    Age : 77
    Location : fishin on Stalin´s Strait between Mexico and Canada

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  GunshipDemocracy on Mon Jun 06, 2016 9:54 pm

    jhelb wrote: George, since you keep track of all the latest development in the Russia, I had one question. A couple of yers ago there were several reports about  a lot of R & D & some mature technology demonstrations on propulsors done in Russia.

    Given the fact that  Pump-Jet Propulsor & MHD-based drives are the way of the future how soon can we see Russian subs with these features?  (France has already incorporated it in the Shortfin Barracuda that it is selling to Australia) Thanks.


    Pump jet propulsion system in russian submarines SMX_Ocean_141029_01

    I see a conventional propeller here no pumpjets. MHD? anybody isntelled this yet? What a Face
    avatar
    Singular_trafo

    Posts : 113
    Points : 105
    Join date : 2016-04-16

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Singular_trafo on Mon Jun 06, 2016 10:09 pm

    jhelb wrote:
    George1 wrote:Sixth Varshavyanka-class sub for Black Sea Fleet launched in Petersburg

    Russia will build diesel-electric submarines for the Pacific Fleet, fifth-generation conventional submarines for the Northern and Baltic fleets

    George, since you keep track of all the latest development in the Russia, I had one question. A couple of yers ago there were several reports about a lot of R & D & some mature technology demonstrations on propulsors done in Russia.

    Given the fact that Pump-Jet Propulsor & MHD-based drives are the way of the future how soon can we see Russian subs with these features? (France has already incorporated it in the Shortfin Barracuda that it is selling to Australia) Thanks.

    Pump jet creating an optimal speed range, so doesn't make so much sense for a diesel sub. It wants to go as fast as possible when using diesel, and can't go fast anyway on batteries.
    jhelb
    jhelb

    Posts : 618
    Points : 715
    Join date : 2015-04-04
    Location : Previously: Belarus Currently: A Small Island No One Cares About

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  jhelb on Tue Jun 07, 2016 9:08 am

    GunshipDemocracy wrote:I see a conventional propeller here no pumpjets. MHD? anybody isntelled this yet?

    DCNS had stated that the Australian Shortfin Barracuda will have Pump Jet propeller. Re MHD, like I said Russia was working on it as was France & Japan. I don't think it has been installed on any sub yet. Back in 1990, the Soviet Union tried to fit a pump-jet of 5,500 hp to one of the Kilos of Black Sea fleet, with the designation 877V

    Singular_trafo wrote:Pump jet creating an optimal speed range, so doesn't make so much sense for a diesel sub. It wants to go as fast as possible when using diesel, and can't go fast anyway on batteries.

    Pump jets are indeed heavier, but so much quieter. The big advantage pump jets offer is providing the submarine with a higher tactical 'silent speed'. A conventional propeller submarine may have a silent speed of 7 to 9 knots, the pump jet submarine much higher - speculating in the 'teen' speeds or more
    avatar
    Singular_trafo

    Posts : 113
    Points : 105
    Join date : 2016-04-16

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Singular_trafo on Tue Jun 07, 2016 6:18 pm

    jhelb wrote:
    GunshipDemocracy wrote:I see a conventional propeller here no pumpjets. MHD? anybody isntelled this yet?

    DCNS had stated that the Australian Shortfin Barracuda will have Pump Jet propeller. Re MHD, like I said Russia was working on it as was France & Japan. I don't think it has been installed on any sub yet. Back in 1990, the Soviet Union tried to fit a pump-jet of 5,500 hp to one of the Kilos of Black Sea fleet, with the designation 877V

    Singular_trafo wrote:Pump jet creating an optimal speed range, so doesn't make so much sense for a diesel sub. It wants to go as fast as possible when using diesel, and can't go fast anyway on batteries.

    Pump jets are indeed heavier, but so much quieter. The big advantage pump jets offer is providing the submarine with a higher tactical 'silent speed'. A conventional propeller submarine may have a silent speed of 7 to 9 knots, the pump jet submarine much higher - speculating in the 'teen' speeds or more

    The pump jet increase the required power for the same speed for a sub.

    The increase of speed require three magintude more power, so if the sub can go 200 km with one charge then by doubling its speed it can go for 25km.


    Means that a pump jet diesel sub can be used only for short dashing, not for partoling.
    avatar
    Singular_trafo

    Posts : 113
    Points : 105
    Join date : 2016-04-16

    Pump jet propulsion system in russian submarines Empty Marine propulsion technology for SSKs

    Post  Singular_trafo on Wed Jun 08, 2016 6:13 pm

    Singular_trafo wrote:
    jhelb wrote:
    GunshipDemocracy wrote:I see a conventional propeller here no pumpjets. MHD? anybody isntelled this yet?

    DCNS had stated that the Australian Shortfin Barracuda will have Pump Jet propeller. Re MHD, like I said Russia was working on it as was France & Japan. I don't think it has been installed on any sub yet. Back in 1990, the Soviet Union tried to fit a pump-jet of 5,500 hp to one of the Kilos of Black Sea fleet, with the designation 877V

    Singular_trafo wrote:Pump jet creating an optimal speed range, so doesn't make so much sense for a diesel sub. It wants to go as fast as possible when using diesel, and can't go fast anyway on batteries.

    Pump jets are indeed heavier, but so much quieter. The big advantage pump jets offer is providing the submarine with a higher tactical 'silent speed'. A conventional propeller submarine may have a silent speed of 7 to 9 knots, the pump jet submarine much higher - speculating in the 'teen' speeds or more

    The pump jet increase the required power for the same speed for a sub.

    The increase of speed require three magintude more power, so if the sub can go 200 km with one charge then by doubling its speed it can go for 25km.


    Means that a pump jet diesel sub can be used only for short dashing, not for partoling.

    Sorry, my mistake.I should spend a bit more to think andcalculate prior of writing. : )

    The reqired power of the motor increasing cubicaly with speed, the range decreasing by sqare of the speed.

    so twive as high speed means quoter the range, so from 200 km to 50 km.
    avatar
    Arrow

    Posts : 427
    Points : 427
    Join date : 2012-02-12

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Arrow on Fri Nov 02, 2018 9:27 am

    Yasen-М has a higher noise level than Virgini, Seawolf, Astute. Still use standard screw. Modern nuclear submarine use pump jet propulsion which is more efficient and quieter. Very expensive design and it has old technologies like standard screws and is not equal in terms of stealth to western submarine.
    Hole
    Hole

    Posts : 2268
    Points : 2266
    Join date : 2018-03-24
    Age : 43
    Location : Merkelland

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Hole on Fri Nov 02, 2018 10:39 am

    You have some proof for your claims? Personal recordings of the sound levels?
    avatar
    Arrow

    Posts : 427
    Points : 427
    Join date : 2012-02-12

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Arrow on Fri Nov 02, 2018 10:47 am

    Simply Pump jet is quieter than a traditional screw. Therefore, everyone except Russians apply this to their SSN.
    GunshipDemocracy
    GunshipDemocracy

    Posts : 4913
    Points : 4943
    Join date : 2015-05-17
    Age : 77
    Location : fishin on Stalin´s Strait between Mexico and Canada

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  GunshipDemocracy on Fri Nov 02, 2018 11:25 am

    slasher wrote:Not a very flattering assessment at all of the Project 885M.

    and that's assessment for admin of forum komandir k-244. about author of article: Maxim Klimov:

    http://komandir.k-244.ru/index.php?option=com_content&view=article&id=139&catid=44&Itemid=137


    Mr. "2503", "Maxim", "vpk-news.ru/articles/6766", "Maxim Klimov"! I do not know what your pseudonyms are, but what is the real name. You are probably a very secret developer of underwater weapons that you are afraid to introduce yourself. You are so secret that even correcting me in the device and the combat use of torpedo weapons, speak in hints. It can be seen that you are afraid that the imperialists may kidnap you, introduce a “truth serum” and you will tell those “trifles” without which torpedoes will not be fired. Do not be afraid, even your “Aunt Frosya” knows that before a torpedo shot it is necessary to equalize the pressure in the torpedo tube with the outboard and open the front cover.


    Your snobbery, eloquent language, aplomb, unwillingness to listen to the interlocutor prevents you from being an interesting interlocutor at the Forum. Asking me a question: “Where does the aerodynamic lift force in the atmosphere go when firing ballistic missiles?” And sending me to teach “a simple physics textbook,” you thereby demonstrate the elementary stupidity. Do you, in general, imagine what it is about? Can you tell a plane from a ballistic missile? After such statements, there is a doubt in your competence in military matters


    Justt I would not go extreme with one negative (in most of his publications) anonymous guy.
    GunshipDemocracy
    GunshipDemocracy

    Posts : 4913
    Points : 4943
    Join date : 2015-05-17
    Age : 77
    Location : fishin on Stalin´s Strait between Mexico and Canada

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  GunshipDemocracy on Fri Nov 02, 2018 11:26 am

    Arrow wrote:Simply Pump jet is quieter than a traditional screw. Therefore, everyone except Russians apply this to their SSN.

    and surely without the reason, you must be a sub designer? Why Russians bother with 2 engines fighters when perfect F-35 can fly with one? (barely tho)




    Hole wrote:You have some proof for your claims? Personal recordings of the sound levels?

    Nope, he doesent. How cam you have any signature of top secret subs? from "The Sun"?
    avatar
    slasher

    Posts : 49
    Points : 49
    Join date : 2015-09-28

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  slasher on Fri Nov 02, 2018 12:51 pm

    GunshipDemocracy wrote:Justt I would not go extreme with one negative (in most of his publications) anonymous guy.

    I really hadn't done any background research on him. I agree of course that's very important, especially in understanding what an author's narrative agenda is about. Other articles I've read from him are critical in nature as well.
    That said, he does appear to be somewhat well researched, and I do expect that with his critical p.o.v. he will have many detractors.

    In examining his assertions, here's an article (for some balance) in response to some of his claims from an alleged former submariner.

    The Failure of Russia’s Submarine Fleet

    All in all, the fact that the Ru Navy has seen it necessary to upgrade to improved versions of both the 955's and 885's shows that they appreciate the need to try to stay ahead on the technological curve. Even now, improvements to these are being worked out in the so-called Husky sub project. That's a good sign showing they accept improvements are needed in order to at least maintain a level of parity with their contemporaries into the foreseeable future.
    GunshipDemocracy
    GunshipDemocracy

    Posts : 4913
    Points : 4943
    Join date : 2015-05-17
    Age : 77
    Location : fishin on Stalin´s Strait between Mexico and Canada

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  GunshipDemocracy on Fri Nov 02, 2018 2:45 pm

    slasher wrote:

    All in all, the fact that the Ru Navy has seen it necessary to upgrade to improved versions of both the 955's and 885's shows that they appreciate the need to try to stay ahead on the technological curve. Even now, improvements to these are being worked out in the so-called Husky sub project. That's a good sign showing they accept improvements are needed in order to at least maintain a level of parity with their contemporaries into the foreseeable future.

    Very true.

    As for guy: I dont say his arguments are not relevant. In order improve solutions one always needs constructive critics. But between critics and constructive critics I can see important difference. In Ru Navy perhaps things are not perfect but his constant complains make either RuN is not knowing what to do or he is just too grumpy Suspect Suspect Suspect

    I'd just prefer to be remain prudent abut both saying 885M is perfect or failure. Just is nice if arguments form both sides are balanced. Truth is usually somewhere ein between ;-)
    PapaDragon
    PapaDragon

    Posts : 8306
    Points : 8390
    Join date : 2015-04-26
    Location : Fort Evil, Serbia

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  PapaDragon on Fri Nov 02, 2018 8:37 pm

    slasher wrote:Not a very flattering assessment at all of the Project 885M.

    https://vpk-news.ru/articles/45818

    .........................................
    https://www.cna.org/CNA_files/PDF/IOP-2018-U-018268-Final.pdf?fbclid=IwAR2qPqYW2SJytdWyv6HFCOtXnoKWJC1zFdMs_vcAJWZAuijYP_o3BpxuZ4k


    This is that same BS article I posted a while back in my infinite curiosity and whole thing has been proven to be load of crap.


    This suggestion you refereed to is peak stupidity in itself:

    slasher wrote:........ He contends that way too much funding for the navy is being eaten up by a submarine project like this, and instead proper completion of R&D and testing should be carried out, thus slowing production and freeing up resources for surface ships and the naval aviation....


    So idea is to defund only component of Russian Navy that even remotely works in favor of decrepit, hopelessly obsolete and outclassed surface fleet and barely existing carrier aviation that could never be able to counter even a single 2nd tier western Navy let alone something like USN?

    I will say what I said before: if submarine fleet is not good enough then any investments in any kind of navy, surface one especially are nothing more than criminal negligence and treason.

    Operating surface navy under conditions described in that article is tantamount to mass murder of Russian naval personnel.
    Singular_Transform
    Singular_Transform

    Posts : 738
    Points : 728
    Join date : 2016-11-13

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Singular_Transform on Fri Nov 02, 2018 8:54 pm

    Arrow wrote:Simply Pump jet is quieter than a traditional screw. Therefore, everyone except Russians apply this to their SSN.

    Pump jet works only in a narrow range of depth.

    It increase the pressure of the water , and due to that it decreased the aviation.

    Problem is as the sub dive deeper the pressure increase, so the sub could be capable to go faster, but above the optimal design speed the pump jet assy is decrease the maximum speed, and (potentially ) even can increase the noise as well.

    And it means at the same time the maximum speed of a boat due to pumpjet is decreased.
    avatar
    kumbor

    Posts : 286
    Points : 284
    Join date : 2017-06-09

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  kumbor on Tue Nov 06, 2018 7:38 pm

    Singular_Transform wrote:
    Arrow wrote:Simply Pump jet is quieter than a traditional screw. Therefore, everyone except Russians apply this to their SSN.

    Pump jet works only in a narrow range of depth.

    It increase the pressure of the water , and due to that it decreased the aviation.

    Problem is as the sub dive deeper the pressure increase, so the sub could be capable to go faster, but above the optimal design speed the pump jet assy is decrease the maximum speed, and (potentially ) even can increase the noise as well.

    And it means at the same time the maximum speed of a boat due to pumpjet is decreased.

    And also, pump jet is less efficient when sailing at slow speed.
    Big_Gazza
    Big_Gazza

    Posts : 1603
    Points : 1605
    Join date : 2014-08-25
    Location : Melbourne, Australia

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Big_Gazza on Wed Nov 07, 2018 4:13 am

    Arrow wrote:Simply Pump jet is quieter than a traditional screw. Therefore, everyone except Russians apply this to their SSN.

    What simplistic empty-headed tosh...

    Its not a black and white engineering issue. Pump jets may be quieter at mid-high speeds (they are actually less efficient at low speeds), but they reduce the effective available power at high reactor settings. Russian philosophy seems to be that stealth is only useful until the first torpedo is fired. On contact with enemy SSN, the Ruskies probably consider stealth to be no longer useful and that raw kinetic performance, powerful active sonar, and effective counter-measures are the key to victory & survival. Once in combat, SSNs are not going to trade torpedo salvoes at low speed while trying to run silent. Active sonars will be switched on to maximise situational awareness of the enemy, and if it lights up your own boat like an underwater Motorhead concert, well so be it as long as it paints the bogey so he can't continue to hide. I think a pump jet is a disadvantage in this scenario for an SSN engaged in a high-energy knife fight.

    SSBNs are a different case as they need to maximise stealth to avoid detection over their full cruising speed ranges. The need to operate at high speed is limited to specific scenarios like attempting to flee from a hostile enemy SSN (rather than attempting to fight), but this is less important than stealth maximisation to optimize the chance of no-detection in the first place.

    The use of pump jets by USN/UK/French SSNs, and the lack of such on Yasens, is most likely to be a doctrinal issue, not technological.
    avatar
    kumbor

    Posts : 286
    Points : 284
    Join date : 2017-06-09

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  kumbor on Sat Dec 08, 2018 11:44 am

    Big_Gazza wrote:
    Arrow wrote:Simply Pump jet is quieter than a traditional screw. Therefore, everyone except Russians apply this to their SSN.

    What simplistic empty-headed tosh...  

    Its not a black and white engineering issue.  Pump jets may be quieter at mid-high speeds (they are actually less efficient at low speeds), but they reduce the effective available power at high reactor settings.  Russian philosophy seems to be that stealth is only useful until the first torpedo is fired.  On contact with enemy SSN, the Ruskies probably consider stealth to be no longer useful and that raw kinetic performance, powerful active sonar, and effective counter-measures are the key to victory & survival.  Once in combat, SSNs are not going to trade torpedo salvoes at low speed while trying to run silent.  Active sonars will be switched on to maximise situational awareness of the enemy, and if it lights up your own boat like an underwater Motorhead concert, well so be it as long as it paints the bogey so he can't continue to hide. I think a pump jet is a disadvantage in this scenario for an SSN engaged in a high-energy knife fight.

    SSBNs are a different case as they need to maximise stealth to avoid detection over their full cruising speed ranges.  The need to operate at high speed is limited to specific scenarios like attempting to flee from a hostile enemy SSN (rather than attempting to fight), but this is less important than stealth maximisation to optimize the chance of no-detection in the first place.

    The use of pump jets by USN/UK/French SSNs, and the lack of such on Yasens, is most likely to be a doctrinal issue, not technological.

    @Big gazza. I agree with you! While pump jet is quieter on mid/high speed, it is less efficient and makes sub less manoeuverable at low speed. The question is one of doctrine and not of technology, that`s true.
    GarryB
    GarryB

    Posts : 22039
    Points : 22583
    Join date : 2010-03-30
    Location : New Zealand

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  GarryB on Sun Dec 09, 2018 2:59 am

    Regarding the pump jet stuff... Russia has a sub with a pump jet... a model of the Kilo class was fitted with a pumpjet and it was tested thoroughly... they have had plenty of time to learn all the features of such a propulsion system, and yet clearly they have not chosen to fit them to Yasen class subs.

    The reason might be as mundane as the areas where Yasen is expected to operate has lots of seaweed and old fishing nets that could easily jam up a pump jet and render it useless, or it might not be as wonderful as everyone claims and have some serious issues that make it not worth it.... you know... like a 100% focus on stealth for aircraft...
    avatar
    kumbor

    Posts : 286
    Points : 284
    Join date : 2017-06-09

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  kumbor on Sun Dec 09, 2018 10:02 am

    GarryB wrote:Regarding the pump jet stuff... Russia has a sub with a pump jet... a model of the Kilo class was fitted with a pumpjet and it was tested thoroughly... they have had plenty of time to learn all the features of such a propulsion system, and yet clearly they have not chosen to fit them to Yasen class subs.

    The reason might be as mundane as the areas where Yasen is expected to operate has lots of seaweed and old fishing nets that could easily jam up a pump jet and render it useless, or it might not be as wonderful as everyone claims and have some serious issues that make it not worth it.... you know... like a 100% focus on stealth for aircraft...

    If inflow to pump jet is constructed properly, with sufficient opening at the fore end, pump jet is easily cleaned by simply reversing pump jet! Otherwise, classical propeller must be stopped and divers sent to free the propeller of clogged objects. That`s what I think. May be i am wrong!?
    chinggis
    chinggis

    Posts : 44
    Points : 49
    Join date : 2015-06-11
    Age : 52
    Location : karlovac, croatia

    Pump jet propulsion system in russian submarines Empty Pump jet propulsion system in russian submarines

    Post  chinggis on Sun Dec 09, 2018 12:01 pm

    If inflow to pump jet is constructed properly, with sufficient opening at the fore end, pump jet is easily cleaned by simply reversing pump jet! Otherwise, classical propeller must be stopped and divers sent to free the propeller of clogged objects. That`s what I think. May be i am wrong!?[/quote]

    No, it is like any other classical propeller, if it is something clogged, propeller must be stopped and manually cleaned. Pump jet is similar to jet engine, you have a blades on rotor and a blades on stator, if you do not have this type arrangements you have a ducted propeller and that is other story. Only good thing with pump jet is higher speed and lover noise, actually it produce high frequency noise which is more muffled in water than low frequency noise produced by classical propeller. Explosion of 1kg TNT at Gibraltar strait, you can hear in entire west Mediterranean up to West coast of Greece because explosion produce low frequency noise and low frequency noise have a better propagation than high freq. noise.
    Big_Gazza
    Big_Gazza

    Posts : 1603
    Points : 1605
    Join date : 2014-08-25
    Location : Melbourne, Australia

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Big_Gazza on Sun Dec 09, 2018 11:33 pm

    GarryB wrote:Regarding the pump jet stuff... Russia has a sub with a pump jet... a model of the Kilo class was fitted with a pumpjet and it was tested thoroughly... they have had plenty of time to learn all the features of such a propulsion system, and yet clearly they have not chosen to fit them to Yasen class subs.

    The reason might be as mundane as the areas where Yasen is expected to operate has lots of seaweed and old fishing nets that could easily jam up a pump jet and render it useless, or it might not be as wonderful as everyone claims and have some serious issues that make it not worth it.... you know... like a 100% focus on stealth for aircraft...

    Furthermore, the 3x in-service Borei I and the new Borei II all have pumpjets... It's crystal clear that Russia has pump-jet tech in their pocket, and if they are not using it on Yasens then there is a good reason. That will not stop the usual Russophobe trolls and seppo flag-wavers from being stupid however, but thats OK. They should be allowed every opportunity to make fools of themselves Twisted Evil
    Big_Gazza
    Big_Gazza

    Posts : 1603
    Points : 1605
    Join date : 2014-08-25
    Location : Melbourne, Australia

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Big_Gazza on Sun Dec 09, 2018 11:37 pm

    kumbor wrote:If inflow to pump jet is constructed properly, with sufficient opening at the fore end, pump jet is easily cleaned by simply reversing pump jet! Otherwise, classical propeller must be stopped and divers sent to free the propeller of clogged objects. That`s what I think. May be i am wrong!?

    No chance. Suck in a fishing net, and you won't rid yourself of it by reversing prop rotation. By the time you know you have a problem the net will be well and truly ingested and entangled beyond hope. Divers in the water will be needed as a minimum, and that a bit of a problem on a combat mission Very Happy
    avatar
    kumbor

    Posts : 286
    Points : 284
    Join date : 2017-06-09

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  kumbor on Mon Dec 10, 2018 12:50 pm

    Big_Gazza wrote:
    kumbor wrote:If inflow to pump jet is constructed properly, with sufficient opening at the fore end, pump jet is easily cleaned by simply reversing pump jet! Otherwise, classical propeller must be stopped and divers sent to free the propeller of clogged objects. That`s what I think. May be i am wrong!?

    No chance.  Suck in a fishing net, and you won't rid yourself of it by reversing prop rotation.  By the time you know you have a problem the net will be well and truly ingested and entangled beyond hope.  Divers in the water will be needed as a minimum, and that a bit of a problem on a combat mission Very Happy

    Britts use pump jet for over 25 years. Are there any practice how to deal with clogging, if it occured, or if it was admitted!
    chinggis
    chinggis

    Posts : 44
    Points : 49
    Join date : 2015-06-11
    Age : 52
    Location : karlovac, croatia

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  chinggis on Mon Dec 10, 2018 7:16 pm

    kumbor wrote:
    Big_Gazza wrote:
    kumbor wrote:If inflow to pump jet is constructed properly, with sufficient opening at the fore end, pump jet is easily cleaned by simply reversing pump jet! Otherwise, classical propeller must be stopped and divers sent to free the propeller of clogged objects. That`s what I think. May be i am wrong!?

    No chance.  Suck in a fishing net, and you won't rid yourself of it by reversing prop rotation.  By the time you know you have a problem the net will be well and truly ingested and entangled beyond hope.  Divers in the water will be needed as a minimum, and that a bit of a problem on a combat mission Very Happy

    Britts use pump jet for over 25 years. Are there any practice how to deal with clogging, if it occured, or if it was admitted!

    Ship is going into shipyard with floating dock, workers remove clogging material, put new paint on ship, repair what is not repaired last time and when everything is finished, ship sail away, workers got pay and all live in happiness Smile There is no other options because you need special tools and cranes and in many cases you do not have in on ship because it is big, heavy, cumbersome and you dont need it in 99% when ship is sailing.

    Sponsored content

    Pump jet propulsion system in russian submarines Empty Re: Pump jet propulsion system in russian submarines

    Post  Sponsored content


      Current date/time is Thu Oct 17, 2019 11:41 pm