September 27, 2019

Larger diesel sections better for long range submarines. A Dutch Type 212CD?


Following the article of September 23, 2019 Anonymous has kindly provided, in late September 2019, further comments and links here and here. This is on submarine (diesel section) hull diameter matters. Pete has done some editing to put the comments into standard English and added some extra comments in [...] brackets.

The article below is most useful in calculating the probable diameters of the “double hull” (ie. pressure and light outer hulls) of the future Norwegian and German TKMS designed and built Type 212CD (Common Design) and possibly a larger Type 212CD design for the Netherlands.

The German and Norwegian Type 212CD will be designed for short to mid range missions. [But the Netherlands might in future purchase an enlarged (eg. wider diameter (aka beam)) long range (for Caribbean and Middle East missions) version of the Type 212CD. This is noting that the diameter of a double hull around the diesel section, discussed here, may be less than the largest diameter (published beam) measure. The largest diameter published as “Beam: 8.4m” for the Walrus class may be around the crew quarters and/or control room of a submarine, with a small diameter/beam around the diesel section.]

On long range (oceanic) submarine missions diesels must be capable of a relatively complex level of maintenance at sea. [The maintenance crew need space to use large tools and to slide bulky spare parts into the diesels.] This requires sufficient space in the diesel section. The space inside the double hull of the Netherlands’ Walrus submarines is extremely tight for the Walrus’ 3 diesels [1]. Therefore, this space must be improved/enlarged for the Netherlands’ “Walrus Replacement” future submarine.

Case 1: for the fuel cell air independent propulsion (FC AIP) system oxygen tanks and (hydrogen storing) metal hydride cylinders are placed, for safety, outside of pressure hulls (Type 212A style). The outer diameter of the diesel section should be at least 1m wider than the pressure hull [2-4]. This means the [diesel section] diameter of a 212CD is 7.8m ( = 6.8m + 1m). In this case, the maintainability of diesel will not be as good as case 2 (but still better than the Walrus current diesel section beam?). Still having hydrogen and pure oxygen outside the pressure hull is safer.


Case 2: oxygen tanks inside the pressure hull and metal hydride cylinders outside the pressure hull [but still within the light outer hull] (Type 214 style). For better maintainability, the space between each of the 3 diesels should be 400mm-500mm wider (ie. diesel section diameter of 7.5m-7.8m = 6.3m + 400-500mm x 3 [5] [6] ). [This is greater than that of a [2 diesel, maximum 6.3m beam] Type 214 submarine.

Considering Cases 1 and 2, a diesel section diameter of approximately 8m is reasonable (= around 15% wider). Increase of 15% in beam means an increase of 30% in displacement (2,000t for Type 214 becomes 2,600t for a wider beam) [for a Netherland’s Walrus Replacement/future submarine 212CD]. 

[Note this is not suggesting the smaller/standard Type 212CD for Norway and Germany will be 2,600 tons – more likely their 212CDs will be approximately 2,000 tons maximum/submerged].



[1] from https://naviesworldwide.com/navy-news/do-conventional-submarines-need-diesel-engines/ (above) Diesel engines in the Netherland's Walrus class submarine take up a lot of space, require staff and maintenance. [The engine maintainer in the photo looks exposed to the danger of hot engines.] (Photo courtesy Jaime Karremann / Marineschepen.nl)


[2] above is a cutaway diagram from http://gentleseas.blogspot.com/2019/02/tkms-type-212cd-submarine-propulsion.html The complexity of hull diameters along the single diesel 212A above is evident. The maximum diameter of the light outer hull (the "Beam") is known to be 6.8m and the diameter of the pressure hull may be approximately 5.5m. If a 212CD had 2 diesels its pressure and outer hull measures would need to be approximately 1m greater.

[3] https://en.wikipedia.org/wiki/Type_214_submarine
Beam of Type 214 submarine is 6.3m (General characteristics).




[4] from https://ameblo.jp/calorstars/entry-12157790493.html (above) the lower 2 pictures show the installation of the 2 side-by-side diesels into a South Korean Son Won-II (Type 214 variant). These pictures show the tightness of the diesel section [which may be adequate if South Korea's Son Won-II 's are only used for short missions, close to South Korea's naval bases.]

[5] (see an Oyashio engine room below) For Japan's medium range mission 
Oyashio and Soryu class submarines there is more space (perhaps >400mm) between the 2 diesels than in the South Korean Son Won-II/Type 214 engine room in [4]. This permits a higher level of maintenance at sea in the Japanese submarines.


[6] http://japanese.china.org.cn/politics/txt/2012-09/16/content_26536166_12.htm (above) Inside the diesel section of a Japanese Oyashio class submarine. The double hull structure consists of an outer light hull (diameter 9.1m) and inner pressure hull (approximately 7.2m?) for the diesel section. A KAWASAKI diesel is on each side of the metal walkway. 12 square-shaped dark metal cylinder head covers can be seen. 

For Japan's newer generation Soryu submarines 2 x KAWASAKI 12V/25/25 diesels are installed, with a bore of  250mm. The width of the passage is approximately 1.2 m which is considerably bigger than those of a Type 212A [2] or the Walrus sub's crowded and dangerous (?) engine room [1]

A larger space for the diesel section facilitates maintenance of diesels during the long mission (such as 10 weeks) of an oceanic submarine [like Australia's Collins class. With the Collins having 3 diesels but only within a beam of 7.8m is the Collins' engine room crowded?]

Mainly Anonymous (and Pete)

9 comments:

  1. In Collins-class, “one diesel plus two diesels” arrangement is adopted.

    Three diesels (V12 version of 8 PA4 V200 SM [1]) are arranged in parallel in Walrus [2]. Three diesels may be installed in SAAB-DAMEN submarine for Walrus Replacement Program (WRES). In the case of 212CD, if oxygen tanks are installed in the pressure hull, three diesels-arrangement is possible.

    In submarine with a periscope, the control section is always under the bridge, which results in useless movement of crew. For example, if the crew section is in bow side, maintenance crew must pass through the control section.

    A26 (Blekinge-class) submarine equips with optical mast instead of conventional periscope, and the crew comfort and control sections are placed at middle and bow side of submarine, respectively [3]. As a result, there is no useless movement of crew. SAAB-DAMEN submarine for WRES will be non-periscope type.

    212A has two batches (first batch : U31-34, second batch: U35, 36). The latter is 1.2 m longer than the former thanks to additional optical mast. If periscope is abolished in 212CD, more efficient arrangement of the sections like A26 is possible.

    [1] PA4 SM & SMDS, Man Diesel and Turbo
    https://marine.man-es.com/docs/default-source/shopwaredocuments/pa4-sm-smdsfba3ca1740b144429518d4e002fd7d6f.pdf?sfvrsn=6f128e3a_3
    Mechanical output of 12 PA4 V200 SM might be 1050PS (output of 8 PA V200 x 1.5 = 700PS x 3). Then, total output of three diesels in Walrus might be 3150PS. As SAAB-DAMEN submarine will equip with LIBs instead of LAB, two-diesels system (ex. 1300PS x 2= 2600PS for two MTU V12 4000s) is not enough to achieve massive and quick supply of electricity to LIBs.

    [2] “CO2 on Walrus Class Submarines”, LCDR Jos Bogaert, page8, Royal Netherlands Navy, 10/12/2015, https://www.sonistics.com/wp-content/uploads/10-CO2-on-Walrus-Class.pdf

    V12 version of “8 PA4 V200 SM?” is used 12 Man and Diesel (12 P
    [3] “Sweden's Notorious Little Carrier Killing Sub Just Got Some Major Upgrades”, Tyler Rogoway, Jun/20/2018, The Drive.com, Figure “Gotland – > A26”, https://www.thedrive.com/the-war-zone/21662/swedens-notorious-little-carrier-killing-sub-just-got-some-major-upgrades

    ReplyDelete
  2. Thanks Anonymous

    For your comment of September 28, 2019 with links.

    Australia may have done one thing right with the arrangement of its diesels for Collins - that is "Collins-class, “one diesel plus two diesels” arrangement" that you describe. This may have avoided diesel crowding-maintenance problems.

    Meanwhile the Netherlands new sub (Walrus replacement) selection issue may continue for years. This may be a process of very slow elimination of each of the contenders: ie. Naval Group, TKMS, Navantia and Saab - each foreign company allied to a Dutch shipbuilder.

    If the Netherlands wants a LIBs submarine this may suggest the new sub may be non-AIP. Therefore TKMS may offer a small (non-AIP) Type 216 rather than a large Type 212CD (with AIP).

    Regards

    Pete

    ReplyDelete

  3. The chance that the Germans are going to build the Dutch subs are low

    The SAAB-DAMEN team got reinforced with the Britsh Babcock and got the exclusive deal for the UK`s Sonar 2076 suite. This deal will give SAAB-DAMEN (Babcock) team huge leap forward on the Germans.


    (in Dutch)
    https://marineschepen.nl/nieuws/Exclusieve-deal-met-Britten-is-voor-Damen-Saab-belangrijke-stap-031019.html

    ReplyDelete
  4. Based on information from Norway Defense [1], Type 216 [2] and Type 212A, I think Type 212CD is short version of Type 216 with features of Type 212A.

    Propulsion motor: Siemens Permasyn x 1

    Diesels: two V12 4000s (=1300kW x 2)

    Displacement:<3000t (as same as displacement of future Netherlands submarine)

    Beam: 8.1m (same as 216)

    (After correction) Length: 65m [length of 216) x (displacement of 212CD)/(displacement of 216)=89m x 3000t/4000t]

    [Fuel Cell AIP]
    Oxygen tanks: inside of pressure hull (bottom of bow and stern side?)
    Metal hydride cylinders outside of pressure hull (top of pressure hull?)
    Non-CO2 reforming Fuel Cell: 34kW x 9 (same as 212A).
    [120kW x 4 (216) and 120kW x 2 (214) are possible]

    [Additional comment on Non-CO2 reforming Fuel Cell)]:
    Soryu MKI (4,200 ton), Type 212A (1,830 ton) and Type 216 (4,000 ton) equip with 4 Stirling generators (60kW x 4 = 240 kW), 9 FCs (34kW x 8 = 272kW, and one spare) and 4 FCs (120kW x 4), respectively.

    9 FCs may supply enough power in low speed operation of 212CD.

    Pressure hull: non-magnetic stainless steel

    [1] “Gigant investering under vann (Giant investment underwater)”, Forsvarsmateriell, https://forsvaret.no/forsvarsmateriell/prosjekter/prosjekt-nye-ubåter
    “MILESTONES” shows that timing of the offer (212CD) from TKMS to Norway overlaps with that of TYPE 216 to Australia in SEA1000. In the case of submarine design from scratch, its takes 10 years to building and delivery. 212CD is contract in 2019 and its first batch is delivered in 2025. This suggests basic design of 212CD is achieved in mid 2010s. These facts suggest 212CD is based on 212A and 216.

    [2] “Marine Systems Royal Australian Navy datasheet pictures images photos video specification”, Navy Recognition, Dec/29/2011 17,
    http://www.navyrecognition.com/index.php?option=com_content&view=article&id=264

    ReplyDelete
  5. Hi Anonymous [your October 4, 2019 at 3:07 AM]

    Yes certainly a SAAB-DAMEN has been more discussed in the Netherlands than any Dutch company alliance with TKMS or with Naval Group.

    I wonder if the Dutch will decide not to have any AIP. One reason is the longer the typical missions the less likelihood AIP will be economical. Netherlands-Dutch Caribbean and return and Netherlands to Middle East monitoring and return being two typical long range missions.

    Also if SAAB-DAMEN follow the LIBs-Soryu example - LIBs in some ways provides longer full submerged performance between snorts. So there is less need for AIP providing longer full submerged performance between snorts.

    Regards

    Pete

    ReplyDelete
  6. Hi Anonymous [your October 4, 2019 at 4:06 PM]

    I have now added "(After correction) Length: 65m" and "[Additional comment on Non-CO2 reforming Fuel Cell)]" to your original comment

    I agree the Type 212CD could be a short version of Type 216 with features of Type 212A.

    Thankyou for the likely Type 212CD specifications and different AIP arrangements for Soryu MKI, Type 212A and Type 216.

    https://forsvaret.no/forsvarsmateriell/prosjekter/prosjekt-nye-ubåter is interesting

    From http://www.navyrecognition.com/index.php?option=com_content&view=article&id=264 TKMS may have made a feature of AIP in the Type 216 offered for Australia but Australia was not/does not seem to be interested in AIP.

    Therefore TKMS had competitive advantage in offering AIP. Hence TKMS did not win the SEA 1000 competition in 2016. Australia's typically long range mission profile makes AIP uneconomical.

    Regards

    Pete

    ReplyDelete
  7. Hi Pete

    RAN originally did not appreciate TKMS and caviled about noise problem of simulated Type 216.

    SAAB does not like to give up ridiculously expensive Stirling gen. I believe SAAB-DAMEN submarine equips with two MKV Stirling gens whose total output (120kW x 2) is same as four MKIII Stirling gens (60kW x 4) for Soryu MKI. As Stirling gen is mainly used at low speed range and its operation period depends on amount of LOx, adoption of MKV Stirling gen aims reduction of number of Stirling gen to expand effective space.

    In my opinion, the winner in Netherlands submarine race is SAAB-DAMEN, because NAVAL group is busy in building of Attack-class, other Scorpenes and Type Suffren and does not have enough human resource to develop new submarine for Netherlands.

    Regards

    ReplyDelete
  8. Hi Anonymous [your October 4, 2019 at 8:07 PM]

    I would also add Naval Group (manager, designer and worker) human resources will be stretched because there is also the task of designing and building France's next generation SSBNs.

    Hence Australia's Attack class project will suffer delays and cost overruns due to limited Naval Group human resources.

    Regards

    Pete

    ReplyDelete
  9. Winner (SAAB-DAMEN or Naval Group) or implementation of the next selection (SAAB-DAMEN and Naval Group) is decided soon [1].

    [1] “Angling fishing for submarines” Olof van Joolen & Niels Rigter, De Telegraaf, Oct/02/2019,
    https://www.telegraaf.nl/nieuws/45970881/bonden-hengelen-naar-onderzeeboten
    “From an internal comparison that De Telegraaf got insight into, the Dutch / Swedish combination Damen / Saab seems to have the best papers for the billions of orders, but the French Naval Group is chasing the consortium.”

    “The decision about which party or parties will continue to the next round therefore becomes more a political than a technical decision. It should have been dropped last fall. It is now expected in the coming weeks.”

    ReplyDelete

You can comment :)