Dutch Submarines: The Walrus (2) submarine class

Boat	Walrus (2)	Zeeleeuw (2)	Dolfijn (4)	Bruinvis
Pennant #	S802	S803	S808	S810
Call sign	PACU	PASZ	PAFF	PAIT
NAPO #	368	372	322	318
Yard #	348	349	352	353
Type	Conventional attack submarine
Class name	Walrus (2). Named after first of class. Second class named Walrus
Design	Dutch.
Navy estimates	Money set aside in 1975.
Building contract	16 June/Aug 1979	17 Dec 1979	16 Aug 1985	16 Aug 1985
Laid down	11 Oct 1979	24 Sep 1981	12 June 1986	14 Apr 1988
Launched	28 Oct 1985	20 June 1987	25 Apr 1990	25 4/5 1992
Re-launched	13 Sep 1989	-	-	-
Trials				4 Mar - 25 Oct 1993
Commissioned	25 Mar 1992	25 Apr 1990	29 Jan 1993	5 July 1994
Decommissioned	Early 21 century
Design	Dutch: RDM, NEVESBU, VEREBUS, Royal Navy. Improved Zwaardvis (2)
Shipyard	Rotterdamse Droogdok Maatschappij, Rotterdam
Cost	Original 212,500,000 Dutch guilders; later raised to 470,000,000 guilders
Le x Be x Dr	67.73 m x 8.4 m x 6.6 m (7 m according to some sources)
Displ. sur/sub/stnrd	2450 t / 2800 t / 1900 t
Propulsion	Diesel-electric
Engines	Three 12-cylinder 4-stroke PA4 200 VG SEMPT-Pielstick diesel engines, 4.63 MW, 6300 hp(m), 3 alternators 2.88 MW.
Main motor	One Holec electric motor, 6910 apk, 5.1 MW
Batteries	Varta, 420 cells (German Exide type has also been reported)
	In July 2000 the Dutch government reported an order for batteries from Exide Deutschland.
Shaft/Propeller	1 shaft / 5 blades (some sources report 7 blades, which is incorrect)
Speed surf/subm	13 kts / 21 kts
Range snorting	10000 nm at 9 kts
Diving depth	Officially >300 m. Exact diving depth is classified but probably >400 m
Complement	50 up to 55 is being reported. 52 according to the Dutch Navy. 10 off, 12 sub. off., 15 corp., 15 enlisted. Latest figures of the Dutch Navy indicate a crew of 55. 9 Officers, 12 Sub-officers, 34 Corporals and sailors.
Torpedo tubes	4 x 21" bow. Mk 67 NL mod Water-ram discharge from Vickers, Canada Mk 19 turbine ejection pump (TEP).
Torpedo type	Honeywell Mk 48 Mod 4 and Mk 48 ADCAP.
	Honeywell NT 37 C/D/E. Probably only kept on stock at the shore base.
Missiles	SSM: McDonnell Douglas Sub-Harpoon. The class can fire the Sub-Harpoon, but none are bought.
Armament	20 torpedoes or Sub-Harpoon. 40 mines in lieu of torpedoes. 2001: Unconfirmed: Sub-Harpoon not used anymore
Decoys	Type and number unknown.
Fire control	HSA SEWACO VIII action data automation, which is the same as HSA GIPSY data/combat system.
	GTHW integrated Harpoon and Torpedo FCS
Radar	Surface navigational?: Signaal / Decca 1229. Surface search: Signaal ZW-07.
Sonar	Also read the 'notes'
	Towed array: GEC Avionics / Dutch type 2026 with Signaal display processor, Marconi beam-former and an Ameeco wet end; passive search; very low frequency. LRS, Long Range Sonar
	Hull mounted: Thomson Sintra Elodone Octopus; Thomson-Sintra TSM 2272. passive/active search/attack; medium frequency; 64 stave
	?ETBF and Acoustic Telemetry Fenelon; Thomson-Sintra TSM 2225 passive ranging.
	Thomson Sintra DUUX 5, passive ranging and intercept.
	Probably: Flank array FAS 3-1A.
	Probably: Hybrid flank array. Using commercial Interstate Electronics Corp. spectrum analyzer, an HP-1311A display unit , and TNO's interface type JO116 electronic unit.
	Probably: EDO 1550 obstacle avoidance sonar.
ESM	Radar warning: Argo Phoenix I . According to some sources: Argos 700 radar warning.
	In July 2000 the Dutch government reported an order for DR3000 systems from Thomson-CSF Detexis.
	In order to replace the original Kollmorgen antenna's ACAL Nederland delivered an improved ESM early-warning antenna in 1994. These antennas are installed in a watertight dome on the search perisscope. A GPS antenna is included in the same dome.
	In 2000 ACAL Nederland delivered an upgrade. The upgrade consists of an expansion as well as improvement of the antenna specifications.
Periscopes	Search: Kollmorgen type 76, designation for this Walrus (2) version is type 979 Attack: Kollmorgen type 76, designation for this Walrus (2) version is type 978
	Some sources report 2 x Barr & Stroud, which is incorrect.
Communications	Late 1998: Radio Holland Marine GMDSS communications equipment, details.
Notes	- Equipped with Hydraudyne drive and controls - Improved Zwaardvis (2) class with similar dimensions and identical silhouettes except for the X-stern. Use of new H.T. steel increased the diving depth by some 50 percent. - New fire control, command and automation system reduced the crew from 65 to 49. In 1981 various changes to the design were made which resulted in a delay of 1-2 years. Equipped with DSRV lock. - In March 1996 talks between RDM and China, concerning Walrus class type submarines, are reported. - In 1998/1999 the Dutch company Nedinsco delivered new plotting tables for these boats. - The CUP of these subs will possibly incorporate: New batteries with more capacity and a longer lifecycle; Updated SEWACO; New MRS; New processing unit for the LRS; Several 'brown water' adjustments including Harpoon II system. - Research for the use of anechoic tiles on these boats has been reported. - A lot of equipment, including towed array gear, is stored in the UK. - The subs will be refitted/modernized around 2009. AIP will be one of the possible improvements. - Water maker produces 2000 litres a day (2002 data) - In March 2003 the "U.S. Office of Naval Research" wrote: "The Netherlands is working to extend the life of these ships to 2025. Most of the discussion cantered on improved signal processing to extend the capability of the existing sensor arrays. The Walrus-class has an ahead looking sonar, a 24 element single line flank array and a towed array. It also has three hydrophones spaced along both the port and starboard sides for passive ranging. There was discussion of conventional and adaptive beam forming, inverse beam forming, and synthetic aperture processing techniques. The objective is to improve the performance of the flank array to that of the towed array, even at higher tow speeds. The passive ranging system uses three single hydrophones spaced along the side of the submarine." - When the RN stopped using this type of towed array the Dutch Navy took over the gear. It is now stored at the ODC (storage and distribution center) in Den Helder. - The tender Mercuur (4) can be equipped with a facility to attach a towed array to the Walrus (2) class submarines on location. It is also possible to hire a third party vessel on location.

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