Last updated: 18-03-2024
[deepl] Now that it is known that the cabinet prefers to go into partnership with Naval Group to build new submarines, the question is what the French have proposed. Very little has been shared by either side about them yet, but the outlines can already be sketched.
This article has been updated with new information or information confirmed by Naval Group.
Naval Group's proposal for the Netherlands. The first thing to notice are the dive rudders on the sail. Those forward diving rudders are at the front of the French boats (as they are on the three-cylinder submarines). On the Scorpène, Walrus and thus this Blacksword Barracuda, the diving rudders are attached to the sail. (Image: Naval Group)
On Friday afternoon, a Defence spokesperson informed NavalShip.com that the specifications of the design were still in a confidential annex and that what would be released when would still be looked at. However, Naval Group had already shared an overview of specifications through a press release on Friday afternoon. Based on this, the information shared with
Marineschepen.nl and others during previous press visits to Cherbourg and analyses by experts, we are trying to form a better picture of the French proposal.
New design in family
As is known, Naval Group is now building six Barracuda class nuclear submarines for the French navy. Naval Group also builds submarines for export, which are the smaller diesel-electric Scorpènes. The largest of that family is about 2,000 tonnes and some have outside-independent propulsion (AIP). These were sold to Chile, Malaysia and India, among others. In 2016, a data breach exposed 22,400 pages about these submarines.
The Netherlands, if the proposed decision is thus approved by the House of Representatives, will neither purchase the Barracuda nor the Scorpène. This will be a diesel-electric design that sits between the Barracuda and Scorpéne in terms of size, a design that may well be seen as a new design. Although elements of these boats will be used. Admittedly, a diesel-electric version of the Barracuda is not in itself new; Australia
is [was] said to get such a version with the Shortfin Barracuda. Yet there are major differences between the design for the Australians (which was far from finished when the contract was torn up), the Barracuda and the so-called Blacksword Barracuda, as Naval Group has called the design for the Netherlands.
Barracuda - Lenght: 99.5m; Diameter: 8.8m; Déplacement: 5300t; Crew: 60
Shortfin Barracuda - 99m; 8,8m; 4765t; 60
Blacksword Barracuda (Orca class)- 82m; 8.2m; 3300t; 35-40
Naval Group's sheet with specifications of the proposal. (Source: Naval Group)
At the front in this openwork model of the Blacksword Barracuda, you can see a grey cylinder, which is the sonar in the bow. The white tubes are the torpedo tubes. The red part behind the tubes is the bow tube chamber. So this is not as high as in the Walrus class. Above that is the accommodation (yellow). The orange cubes at the bottom are the batteries located front to back in the battery bay. The green part on the upper deck appears to be the command centre. Further aft, part of the engine room can be seen (beige) and the electric motor (purple). No pumpjet, but propeller is drawn here. (Image: Naval Group)
Diameter
Almost all of the above specifications are in line with expectations. What stands out is the smaller diameter of the pressure skin. It is even smaller than the largest diameter of the Walrus (8.4 metres), although the Walrus is not a straight design. A diameter sixty centimetres smaller than the original design (the Barracuda) does not seem like much, but it is. According to strict
[ze] German doctrine, it is a new design if the diameter deviates by more than 20 cm; the Swedes and French are slightly more flexible on that. But it has many implications for the boat's layout anyway. Taking over designs from the Barracuda and Shortfin Barracuda, this makes it quite a bit trickier.
Why the diameter is smaller is anyone's guess. Possibly because the designers wanted to stick to the 3300 tonnes and needed length. Then the boat has to be made narrower.
Propulsion
On top of that, of course, comes propulsion. Nuclear propulsion impacts the whole boat, despite the fact that even a nuclear boat has emergency diesels and some batteries. A conventional submarine is completely packed underneath with hundreds of battery cells. The Barracuda has a nuclear reactor in the middle; a conventional boat has the diesels a little further aft. A nuclear submarine never lacks power, the diesel-electric boat has batteries and has to be economical. The designer of a diesel-electric boat has to deal with many systems that (with the air around them) are lighter than water, and thus a boat that can have trouble going underwater. A nuclear boat does not have that problem or less because of the heavier nuclear propulsion equipment. All this affects energy balance (is there enough power?), heat (enough cooling?), weight balance (is the boat straight in the water?) and much more. It needs to be redrawn.
So the propulsion of the Shortfin Barracuda and Blacksword Barracuda is diesel-electric. This means that the submarine can use the diesels (e.g. underwater with the sniffer mast protruding above the water) to charge the batteries. Naval Group uses German diesels for the nuclear submarine and for the Scorpènes as well. More precisely, the Scorpènes have diesels from MTU. This manufacturer has recently launched the MTU 4000 and, with advice from tkMS, it has been specially made for submarines. This engine is considered one of the best submarine diesels at the moment.
For the Shortfin Barracuda, Naval Group had four diesels in mind. For the smaller Blacksword Barracuda, that seems a bit much, especially if you take a high-power diesel like the MTU 4000, but according to the specifications, the Blacksword also gets four diesels. This has implications for the amount of air to be supplied; it can become so large that a larger sniffer mast is needed.
A crucial element of propulsion is the main electric motor. A new permanent magnet motor had to be designed for the Australian boat, one with more than 7 megawatts of power. That is where Jeumont Electric was contracted. For the Blacksword Barracuda, no such power is needed. Experts say 4.5 to 5 megawatts will suffice, but even then: these are not on the market and so Naval Group will turn to Jeumont Electric for a new version, which, incidentally, already has a permanent magnet motor with the Magtronic. Another option is Siemens, which has the Permasyn, but the French are unlikely to go abroad for this.
Finally, the pumpjet. Both the Barracuda and the Shortfin Barracuda were fitted (on the drawing board) with a pumpjet. This is a propeller with lots of propeller blades in a housing and is much quieter (but is heavy and requires a lot of power). Every time Marineschepen.nl visited a Naval Group stand or visited the shipyard, the subject came up and the pros and cons were mentioned. In any case, a pumpjet for a 3,000-tonne boat is quite possible. Based on the illustration on the sheet, a pumpjet does not seem to have been chosen, however.
Off-air independent propulsion
For a long time, outdoor air-independent propulsion (AIP) was seen as a must for new conventional submarines. The Walrus does not have such a system. In the mid-1980s, partly for this reason, the purchase of a fifth and sixth Walrus was abandoned, with well-known disastrous consequences.
Naval Group, Saab and tkMS all have their own systems. Saab uses a stirling engine as a basis, tkMS also equips the new 212CD with a fuel cell-based system. Naval Group also had an AIP with fuel cells.
The advantage of AIP is that the energy does not come from batteries. One drawback is that it is often a large and complex assembly that comes on board, weighing 300 tonnes. Besides, it is only meant for very low speeds (maybe five knots).
Meanwhile, battery technology is much more advanced than in the 1980s, AIP technology has not developed as fast.
Naval Group offered the Netherlands a submarine without AIP and with lithium-ion batteries. Naval Group, incidentally, was not the only provider to make this choice.
Weapons
The Blacksword Barracuda will have
six torpedo tubes (which is more than the Walrus and the Barracuda), just as Australia wanted. These torpedo tubes will have a system that allows them to launch torpedoes, missiles and drones. The latter requires modification because they cannot be launched like the other weapons. Moreover, they must also be able to be taken back on board. Naval Group does not offer an extra large tube for larger drones, as Saab does.
According to
Mer et Marine, there is room for 30 torpedoes or missiles in the bow tube room. The Submarine Service normally tries to keep this information secret, but the French are a bit more open about it. The Barracuda has 20 racks in the bow tube room.
The Submarine Service has been sailing with US torpedoes for decades. Even on the new boats, the Mk 48 torpedo was to come. Moreover, it was announced last April that the Netherlands would even commission research into adapting Tomahawk to launch them from Walrus-class torpedo tubes.
The choice of these US weapons now seems less certain. Yesterday, Submarine Service commander KTZ Jeroen van Zanten opened the door to French systems.
The F21 is a new heavyweight torpedo for submarines. Both France and Brazil ordered these weapons from St Tropez [smile]. These torpedoes are of course wire-guided like the Mk 48, and in terms of range and speed, the two are not much different. One major difference is that the F21 is an electric torpedo and the Mk 48 uses a special fuel: Otto Fuel II. However, the disadvantage of Otto Fuel is that it is toxic and odourless. One advantage of the US torpedo is that the major US submarine forces also have these torpedoes, launch and analyse them and so a lot is known about them.
The Mk 48 does have a larger explosive load: 293 kg vs 200 kg of the F21.
Tomahawk is, so far, the weapon of choice for the frigates as well. Zr.Ms De Ruyter will launch this weapon off San Diego later this year. For the Barracuda, the MdCN is the deep strike weapon. Both range and warhead of the French missile (1,000 km) are slightly less compared to Tomahawk.
Earlier, it was thought that a US system on a French submarine would be difficult, as both governments do not want to share their secrets.
But Lockheed Martin has created an interface for it so that they can still be part of one system, without directly exchanging data with each other.
Sensors and CMS
Submarines have multiple sonars. The Barracudas have the French Thales UMS-3000 as an integrated sonar suite, consisting of a planar flank sonar on both sides of the boat and a cylindrical sonar in the bow.
The flank sonar will allow the submarine to detect contacts at long distances. In addition, the systems will be able to determine what kind of contact is involved and determine where the contact is located. The length of the boat provides the space for a long sonar and this helps in listening to low frequencies that therefore achieve larger ranges. The cylindrical sonar is also capable of detecting contacts, but mainly for tracking and analysing targets.
A sonar that provides information to the boat at even greater distances is the towed sonar. Such a sonar will also be on the Blacksword Barracuda.
Whether the Blacksword will get the same sonars is not certain, but cannot be ruled out. A Naval Group representative told Marineschepen.nl that it does involve the same sonars and that this is also Naval Group's preference, because otherwise other sonars would have to be integrated.
What is certain is that the Netherlands will not get the same software for the command centre. For a long time, the Netherlands wanted to use Guardion, the CMS developed by Maritime IT, the software arm of Defence.
However, and this is a break with the past, Defence wants to leave as much as possible to the shipyard. So there will be a commercial CMS on the boats. The French CMS, Sycobs, is used on the Barracudas and the core again for the next generation of French boats. There will be a variant on the Blacksword Barracuda, to which the Netherlands can also add applications from other manufacturers.
The Barracuda's command centre has fewer positions than the Walrus has now. What the Blacksword Barracuda's power plant will look like is not known.
Platform automation
The Walrus class' high level of automation caused a stir in the submarine world. This was thanks to the systems of Rietschoten & Houwens (now RH Marine). The Walrus class was thus ahead of its time. New steps are being taken in that area for the new ASW frigates, as can be read here. Thus, the stems for platform management (which thus monitors and controls the engines, valves, pumps, etc.) and the Combat Management System are coming closer together. This step does not yet seem to be reflected in the French designs.
Crew
Although the boats are larger than the Walrus class, there are fewer crew members on board. "35-40 people instead of 50-55 people," said outgoing State Secretary for Defence Van der Maat in his speech yesterday. On the one hand, there is more comfort, but on the other, there are more beds.
Those extra beds are there for special units, for example. According to
Mer et Marine, around 16 extra beds are involved. On the Walrus, there was actually no room for accompanying students or marines (special forces).
/deepl
