DSBV-61 - Archived 9/1997

Outlook

• Current production to end in 1998.
• International market looks extremely slim at the moment.
• Eliminated from Dutch LCF program.

Orientation

Description. Passive towed array surface sonar for the detection and tracking of hostile submarines.

Sponsor

Delegation Generale pour l'Armament (DGA)

10/14 Rue Saint Dominique

F-75997 Paris Armees

France

Contractors

Thomson-Sintra ASM (Activites Sous-Marines)

525 Route des Dolines

BP 157

F-06903 Sophia Antipolis Cedex

France

Tel: +33 92963900

Fax: +33 92963950

Licensee

Thomson-CSF

Hollandse Signaalapparaten

PO Box 42

NL-7550 GD Hengelo

The Netherlands

Status. Production and service.

Total Produced. A total of 20 units were in service or on order by mid-1995. The French Navy has ordered at least 12 DSBV-61 towed arrays. The Royal Netherlands Navy has ordered eight similar Anaconda towed arrays for the Karel Doorman class frigates.

Application. The DSBV-61 is designed to provide surface escorts with a means of passively detecting and tracking hostile submarines.

Price Range. Based on the known costs of comparable systems, a unit price of US$10 million can be projected.

Technical Data

Design Features. The DSBV-61A and DSBV-62C sonar combine long-range monitoring with contact analysis and classification facilities. The DSBV-61 listens for both narrow-band machinery noises and broad-band ocean noise. It has good detection capabilities against both bands and can detect noise in the very low and low-frequency bands. The wet end consists of approximately 50 hydrophones at the end of a 365-m long towing cable. The digital array of DSBV-61 consists of eight modules and has an acoustic aperture of about 300 m.

Operational Characteristics. When conducting a broad-band search, beam forming takes place over the entire horizon and in each of the covered octaves. The provision of two monitors suggests that the DSBV-61A covers two octaves, while the DSBV-62C is restricted to a single octave. The system includes an integral torpedo warning function when used in this configuration. Target tracking and torpedo warning are both carried out automatically.

For narrow-band search, the hydrophones are arranged are arranged to carry out the search function over the entire useful frequency spectrum. More precise analysis is possible on operator steerable bearing channels. LOFAR, DEMON and Audio modes are used to classify the selected targets.

Variants/Upgrades

DSBV-61A This is the version of the DSBV-61 fitted onboard the last three French Georges Leygues class frigates. The dry end consists of five processing cabinets and two display consoles plus two totes.

DSBV-62C This is a lightweight, more compact version of the DSBV-61A designed for use on the Tourville class frigates. The dry end consists of a single processing cabinet with one high-definition display console.

ANACONDA This is the export version of the DSBV-61A sonar system. It uses a Mangouste Mk.2 processing unit and is streamed at a critical angle.

LAMPROIE This is an export version of the DSBV-62C sonar system.

Program Review

Background. During the mid-1970s the French Navy decided to shift emphasis away from Variable Depth Sonar (VDS) toward Towed Array Sonar (TAS). A requirement was issued in the mid-1970s for a passive towed array, and Thomson Sintra ASM (a company formed in the early 1980s by the merger of Thomson-CSF and Sintra Alcatel) received a research and development contract in 1977. Research and development continued during 1978 and 1979, and the DSRX-61X experimental towed array was delivered to the French Navy for trials in mid-1980. This was installed aboard the trial ship FS L'Agenais.

The French Navy conducted tests until late 1984. In early 1985 the system was approved for operational use as the DSBV-61. At that time, the French Navy indicated that the system would be installed aboard the last three units of the F-70 ASW Georges Leygues class, retrofitted to the first four ships of that class and probably installed aboard the F-70 AA Cassard class destroyers and the Lafayette class frigates. The first ship to carry the DSBV-61, the destroyer FS Primauguet, was commissioned in November 1986. Initially the system was not offered to any foreign nations, but in 1987 the French began marketing the system to a few Western allies, particularly the Netherlands and Spain.

In January 1988 the Royal Netherlands Navy indicated plans to order eight Anaconda towed arrays for the Karel Doorman class frigates and one system for shore-based training and spare parts. The Anaconda is a modified version of the DSBV-61A, which was developed for the export market. The Netherlands is not expected to require any systems for other frigates. The order was placed in February 1988.

The last destroyer to receive the system as part of its commissioning sonar suite, the FS Latouche-Treville, commissioned in late 1990. Plans to refit the Lafayette class frigates with the DSBV-62C towed array were abandoned due to the burden of expenditure resulting from the construction of the aircraft carrier FS Charles de Gaulle. In June 1991, the first of the Dutch Karel Doorman class frigates was commissioned. At time of service acceptance, the frigate was incomplete due to the late delivery of the DSBV-61 sonar and numerous other items of equipment, including radar and components of the action information system. This situation has largely been rectified, although the ships of the class still lack their Anaconda towed arrays. These will not be fitted until 1996-98.

Originally, the DSBV-61 was intended to be a partial step towards the SLASM fully integrated sonar system. This would have included a bow sonar, a towed array and/or a VDS unit. Early development trials quickly indicated that SLASM, as then conceived, would have been too large to permit installation on the planned platforms, the Tourville class frigates and possibly the Suffren class destroyers. Originally the towed body for SLASM would have weighed in excess of ten tons. Detailed design engineering reduced this to three tons and, in this form, the first SLASM systems were delivered in June 1995. Full operational capability is anticipated on the Tourville class frigates by mid-1996.

In May 1993, a new joint Anglo-French sonar development program was announced as part of the Project Horizon program to develop a common next-generation frigate for the Royal Navy, French Navy and Italian Navy. This takes the basic SLASM architecture of integrated bow sonar, towed arrays and VDS units feeding into a central processing unit, and is reported to replace the French sensors with British equivalents (a low-frequency active/passive bow sonar, a low-frequency passive towed array and the ATAS active towed array), using French central processing and Italian display technology. The result is a much more compact system capable of being deployed in the appropriate warships.

During early 1996, the Trinational Frigate program (based around Canada, the Netherlands and Germany) took on a much more solid form. The Canadians resolved to fulfill their AAW requirements by rebuilding three of their twelve Halifax class ships, the Germanys by building a variant of their F-123 and the Netherlands by building a new design designated the LCF. Originally, this was to have been a variant of the Karel Foorman class but the process of detail design eliminated any resemblance to the original.

One of the costs of this redesign was the elimination of ASW capability. The LCF will be restricted to ASW self-defense, relying on a hull sonar with no towed array. This eliminates any prospect of repeat orders for the Anaconda sonar for this program

Funding

Development funded by French MoD contract.

Recent Contracts

No contractual information has been made publicly available.

Timetable

Worldwide Distribution

France (7 DSBV-61A on seven Georges Leygues FF and 3 DSBV-62C on three Tourville FF. One shore-based training system for each variant).

Netherlands (8 Anaconda on Karel Doorman FF, one shore-based training system.)

Forecast Rationale

The challenges of moving naval operations out of blue water into the littoral environment have, once again, re-emphasized the values of active sonar over passive systems. The result has been a resurgence of interest in VDS systems and in towed active arrays as compared with the towed passive arrays that dominated the 1970s and 1980s. The Dutch Navy is experimenting with a low-frequency active towed system, the French are bringing SLASM into service, and the Royal Navy is experimenting with a towed active array on three of its Type 23 frigates. None of this bodes well for the DSBV-61.

Financial pressures on the French Navy have increased radically as a result of defense expenditure cuts and the financial burdens resulting from the construction of the aircraft carrier FS Charles de Gaulle. All French Navy programs are under strict review and are unlikely to be funded unless absolutely essential. Casualties of this environment are plans to install the system on the Cassard class destroyers and the Lafayette class frigates. The latter design retains provision for a towed sonar, but users exercising that option (Taiwan) have chosen to adopt the ATAS active towed array rather than a passive system.

The scope for additional DSBV-61A/62C refits has been severely restricted by the financial stringencies afflicting the French Navy and the development of the ATAS and SLASM programs. We are projecting the delivery of four additional DSBV-61A systems (covered by existing orders) for the four earlier Georges Leygues class frigates when these enter the yards for their next refits. At present these ships still carry VDS units. The La Fayette frigates are most unlikely to receive the system during the 1990s; if these ships do receive a sonar, it is more likely they will receive ATAS. The Floreal class corvettes will not be fitted with the system since their primary operational roles do not require such equipment. As with the La Fayettes, if an array became essential, ATAS would be a better solution. Hull strength and severe topweight limitations also rule out DSBV-61 installations on the Cassard class destroyers. The international market is even less promising. Heavyweight towed arrays impose numerous limitations on ship performance, stress the hull, and require much training to use properly. They are of greatest value to navies with an interest in high-technology oceanic ASW. Of the few navies with such interests, Spain has long had many cooperative arrangements with France, but the Spanish Navy already uses the SQR-19 aboard its FFG-7 class destroyers, and it might seek the SQR-18A towed array for any Descubierta or Baleares class upgrades. The sheer scale of production of the US towed arrays and the background of experience in their use, gives them major advantages in competing for the limited existing market.

Ten-Year Outlook