Flotilla 2020 – A Strategic Acquistion

The Finnish corvette program is steadily moving forward, and it is nice to see that the Navy is also becoming more open regarding the project. A while back the Navy published a 20-page long document which in quite some detail went through the background of the project, and how it ended up with four multipurpose corvettes being the vessels of choice for Flotilla 2020. This was followed up by a four page article by captain (N) Valkamo, the Navy’s Assistant Chief of Staff / Plans, published in the personnel magazine Rannikon puolustaja (fi. Defender of the Coast). The latter provide a good overlook over the project, including the background research and some further nuggets of information compared to the longer text.

While the program seems to enjoy broad support amongst the Navy (unsurprising) and politicians, it continues to be something of a hot topic amongst parts of the general population and other service branches. With this in mind, it comes as no surprise that both texts place a heavy focus on the solid groundwork made before the decision to focus on four multipurpose corvettes was made.

First, the nature of the future naval battlefield was predicted, and yes, that include the presence of K-300 Bastion anti-ship missile system. After this, the question of how to cost-effectively solve the missions of the Finnish Navy in this threat environment was looked into, including a number of different configurations with vessels of different sizes and roles and in different combinations. Unsurprisingly, it was concluded that due to operational and tactical flexibility as well as economic factors (including both acquisition and life-cycle costs) a single class of multipurpose vessels was preferable over numerous different designs specialising in one or two roles and operating together. I’ve earlier discussed the issue of trying to coordinate different ships into a working unit, ensuring that the right one is always in the right place. A metaphor could be the merger of light, medium, heavy, infantry, and cavalry tanks as well as the tank destroyer into the jack-of-all-trades Main Battle Tank. Other alternatives that were looked into was transferring whole or part of the missions to air- or ground-based systems, but this was also deemed impossible to implement cost-effectively. Especially as e.g. mining require vessels out at sea in any case.

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An infographic depicting the timeline for all major surface units, including scheduled service date, MLU, decommisiong, as well as roles and capabilities. Source: Finnish MoD

This then caused the slight growth in size compared to the current mine ships, as the vessel needs to be able to fit numerous weapons and their sensors, as well as maintaining the crew complement and provisions needed for prolonged stays out at sea during escort or surveillance missions. Something which hasn’t been widely discussed is the need for speed. While the light fast attack crafts have impressive sprint speed, their ability to transit a high speeds over longer distances isn’t stellar, especially if you encounter adverse weather. In the same way, while a Ferrari might be faster than a Land Rover on the Nürburgring, the roles would quickly be reversed if they set off on a bumpy dirt road through the Finnish forests. The larger size does also allow for the ability to operate in ice, as well as better resistance to combat damage due to compartmentalisation.

Still, the size won’t grow too much. Partly because larger vessels aren’t an end in itself, and partly because both acquisition and life-cycle costs grow with the hull size. The Navy also face an issue with having a limited number of crew members with which to man the vessels. All of these factor in, and has lead to the current design. Importantly, keeping the total length around 100 meters and the draft low means that the vessels can use the current naval infrastructure in the Finnish archipelago, including the current network of secondary bases and the extensive network of inshore waterways.

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The 7 meter long and 900 kg heavy 1:15 scale hull model is pushed through the ice as part of the test program. Source: Finnish MoD

The hull form has been finalised, and scale test have been performed with an eye on different requirements. These include both resistance, manoeuvring, and ice-going capability. In addition, the new propeller design has been tested in full scale on the Navy’s auxilliary FNS Louhi. As was expected, the vessels will have a drop of MEKO-blood in them, as the concept has been fine-tuned by German design bureau MTG-Marinetechnik GmbH.

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FNS Hämeenmaa (02) showing the 57 mm Bofors Mk I. Source: Puolustusvoimat

For the weapons and sensors, the RFI resulted in a number of suitable packages being identified, all fitting within the budget. One of these will then be chosen, with the (foreign) main supplier being responsible for providing an integrated warfighting capability (sensors, weapons, C3I, battlefield management, and so forth). One interesting change which I did not expect was the renaming of the anti-ship missiles from meritorjuntaohjus (sea-defence missile) to pintatorjuntaohjus (surface-defence missile), with the Navy’s new missile being slated to become PTO2020. It is possible that this change reflects the secondary land-attack capability many modern missiles have. The PTO2020 program is handled as its own program as it is destined for both the updated Hamina, the corvettes, and the land-based launchers. As such it is not included in the 1.2 billion Euro price tag of the corvettes, as is the case with the new light ASW-torpedo which will be acquired as part of the Hamina MLU.

In addition to these systems, several systems will also be transferred from the Rauma- and Hämeenmaa-classes, as well as from the already decommissioned Pohjanmaa. These include the deck guns, towed arrays, decoy launchers, mine-laying equipment, and fire control director. The deck gun is an interesting issue, as the Rauma is equipped with the Bofors 40 mm, of which there are four, while the Hämeenmaa feature the 57 mm Bofors Mk I, a considerably more suitable weapon for a corvette. Still, the Mk I is quite a bit older than the corresponding 57 mm Bofors Mk 3 which is found on the Hamina, and as we all know there are only two Hämeenmaa vessels in service. However, it is possible that there are more guns in storage, as the two scrapped Helsinki-class vessels as well as the Pohjanmaa also had a single 57 mm Bofors Mk I each, and the Finnish Defence Forces is famous for not throwing away something that might prove useful further down the line. As a matter of fact, I wouldn’t be surprised if the current guns mounted on the Hämeenmaa-class are these recycled Helsinki-class guns… In any case, I expect to see the 57 mm Bofors L/70 mounted on the corvettes, and probably upgrade to a Mk 3-ish standard in order to be able to fire smart ammunition remotely.

The decoy launcher is more straightforward, as both classes feature the modern Rheinmetall MASS. The towed arrays currently in service are the active Kongsberg ST2400 variable-depth sonar and the SONAC PTA passive sonar. Very little information is available on the latter, but it is understood to be a rather conventional system well suited for littoral operations with both narrow- and broadband waterfall displays. As the current number of arrays has been quite small, and as the Hamina will also take up the ASW-role as part of their MLU, it is entirely possible that more arrays will be acquired. It is also unclear if all corvettes will get both active and passive arrays, or whether they will be limited to either mode of operation.

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The scale model shown by Saab at Euronaval 2016, featuring a Giraffe 4A and a 1X above it in the cut-outs. This combination of shrouded rotating radars (the cut-outs are for illustrative purposes only) gives both long-range search capability and short-range tracking of rapidly closing targets. Photo: Saab, used with permission

Interestingly, the fire-control sensor is the Saab CEROS 200 radar and optronic tracking fire control director. This will likely strengthen Saab’s already strong offering, as they already have a tried solution for integrating the CEROS into their 9LV combat managment system, together with their RBS15 MK3 missile and Sea Giraffe radars. The 9LV is already a familiar product to the Finnish Navy, and it would come as no surprise if Saab would be the prime contractor for systems integration. Other companies likely in the running include Atlas Elektroniks (prime contractor for the ongoing Pansio-class MLU), Kongsberg (best known for the NSM anti-ship missile, but has a wide portfolio of naval products), and Raytheon (sporting strong references).

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Further Developments of Squadron 2020

The Finnish Navy has released further details on the upcoming corvettes. To begin with, RMC of Rauma has signed a letter of intent with the Finnish Defence Forces for the construction of the vessels. This has been expected, as of the three shipyards in the country capable of producing ships of this size, Artech Helsinki is Russian-owned and Meyer Turku has filled their production capacity for the foreseeable future. RMC has also teamed up with Patria to ensure that the newly-founded company has the economic and logistical muscle behind them to manage a project of this size. This might be crucial, as if RMC would fail the reviews currently being undertaken, there exists a very real risk that the vessels will have to be built abroad. A special arrangement is that the Finnish Defence Forces remains responsible for the design work, with the yard handling only the building process. This is to make possible the fast delivery schedule.

An interesting article in this year’s edition of Finnish Defence Force’s Insinööriupseri, a publication published yearly by the Engineer Officers’ Association (engineer as in “practitioner of engineering”, not sappers/pioneers). This includes not only articles on the subject, but also new renders and pictures from the research program.

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One of the new renders, showing the refined corvette concept. Source: Finnish Defence Forces / Insinööriupseeriliitto

Unlike the earlier renders, the concept is shown only from the sea level, meaning that several of the details that could be made out from the earlier bird’s eye views are not visible. Still, a number of important changes can be made out.

The most obvious one is that the single-panel rotating radar of the earlier renders have been replaced by a multi-panel fixed installation on a large mast of a truncated pyramid shape. This would mark a significant step up in detection capability and response time, as well as offering better stealth characteristics. Notably, the TRS-4D, successor to the TRS-3D currently found on the Hamina- and Hämeenmaa-classes, is available in both configurations.

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76 mm OTO Melara Super Rapid of the Norwegian Nansen-class frigates. A possible future Finnish deck gun? Source: Wikimedia Commons/Ketil

The only weapon system visible is the fore-mounted gun, which is reminiscent of the BAE 5” (127 mm) Mk 45 Mod 4 turret. If so, this would be the smallest class to be equipped with this weapon, and while not impossible, more likely the turret in the picture is just a generic placeholder, with a 3” (76 mm) weapon being the likely choice.

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All four sisters moving in column in their home waters. Source: Finnish Defence Forces / Insinööriupseeriliitto

The general design has also received a more pronounced twin mast setup, with the front mast holding the four-panel radar and sporting what seems to be an ESM-antenna on top. The rear masts holds an additional array of different antennas, and probably shrouds the funnel to reduce the IR-signature. This is a setup suspiciously similar to that employed by TKMS in recent MEKO-designs, including on the upcoming German F125-frigates and the (failed) MEKO-D bid to Australia. This is not to say that TKMS necessarily is involved in the design, the basic principle of splitting up prioritised systems for greater redundancy by physically separating them is common sense and not uniquely German. However, TKMS would be a logical partner for the “international cooperation and technology sharing [that] has occupied an important role in the project”, and the truncated front mast does bear a strong resemblance of the designs used for an early F125 draft and the aforementioned Australian concept. For the F125 concept, note not only the truncated pyramid form, but also the ESM-antenna on top of it, and wire antennas stretching from the front to the rear mast.

It is also mentioned that the US Navy has been the single most important partner up to this point, and that this is a natural continuation of a collaboration that has been taking place for close to ten years already.

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Propeller testing for Squadron 2020 showing cavitation on the propeller tips. Source: Finnish Defence Force / Insinööriupseeriliitto

The hull shape seems more or less finished, with tank testing having been performed in 1:15 scale, both as towed and self-propelled model. The propulsion will be of a traditional kind, with two shaft lines sporting a single propeller each. The propellers are a minor project on their own, and are set to be of a highly advanced design. This is due to the somewhat conflicting demands of high top-speed, small diameter (due to overall draught requirement),  and low noise (and high cavitation margin). All this, while at the same time being strong enough to cope with ice. This creates significant metallurgic and hydrodynamic challenges, but high-level propeller design is also an area of expertise found both in Finland and amongst our close friends abroad (including Sweden). Suffice to say, this isn’t on my top-five lists of things to be worried about in the program.

Also check out there earlier posts on the programme, including my discussion on the use of vertical-launch systems (VLS) for some serious surface-to-air capability and the general need for corvettes.