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.

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The most obvious one is that the single-panel rotating radar of the earlier renders have been replaced by a multi-panel fixed installation on a large mast of a truncated pyramid shape.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.

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.

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.

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.

MTA 2020 – Propulsion and the state of the Finnish Maritime Industry

As I mentioned on Twitter when publishing my last post, there are two further parts of the MTA 2020 project that deserves attention, but which due to space considerations were left out of the original post: propulsion and the vessels’ country of origin.

The propulsion method has so far not been mentioned. There are basically two kind power sources for corvettes, diesel engines and gas turbines (there are also LNG-powered vessels, but the technology is probably deemed not mature enough for warships). Gas turbines are compact and give much power, but are extremely fuel thirsty. Diesels on the other hand give excellent fuel economy, but doesn’t reach the same power (for any given size) as gas turbines. Gas turbines and diesels can also be installed together in a bewildering array of different methods, with gearboxes allowing them to propel the same shafts, sometimes at the same time, giving a setup where a vessel can cruise on diesels and use the gas turbines for high speed work. In some vessels, the diesels and/or gas turbines don’t drive the shaft directly, but instead work as giant generators, driving electrical engines mounted on the shafts. There are several nice things about an electrical drive, one of which is that instead of a giant turning steel shaft passing from the engine room to the screws, you can use cables. It also allows for a freer placement of the engines, as they don’t have to be in line with the propeller shaft (or gearbox shaft). Yet another option is to have the diesels and gas turbine all driving their own shafts. One of the more innovative is the South African MEKO A-200SAN Valour-class frigate, which features twin diesel engines driving two propellers, and a gas turbine driving a Wärtsilä waterjet.

MTU-CODAG-Antriebssystem Als Systempartner entwickelt und liefert MTU auch komplette Antriebssysteme für Marine- und Behördenschiffe. Kombinierte Antriebssysteme aus Dieselmotoren und Gasturbinen (im Bild: MTU CODAG-Anlage) verbinden die Vorteile beider Antriebssysteme: Bei Langstreckenfahrten oder bei niedrigen Geschwindigkeiten laufen allein die Antriebsdiesel, während für Höchstgeschwindigkeiten die Gasturbine zugeschaltet werden kann. MTU CODAG Propulsion System As system partner, MTU also develops and delivers complete propulsion systems. Combined diesel engine and gas turbine propulsion systems combine the benefits of both propulsion systems (pictured: MTU CODAG system): for long-distance cruising or when traveling at low speed, the propulsion diesel engine only is used, whereas for high-speeds, the gas turbine can be added.
MTU CODAG Propulsion System. Combined diesel engine and gas turbine propulsion systems combine the benefits of both propulsion systems: for long-distance cruising or when traveling at low speed, the propulsion diesel engine only is used, whereas for high-speeds, the gas turbine can be added. Note the size of the gearboxes used to transfer the power from the different power sources to the shafts. Source: Rolls-Royce Power Systems AG press picture

Needless to say, the more complex the propulsion system, the more space it takes, and while gas turbines might be compact, the need for more fuel and larger air and exhaust ducts usually negates this benefit. As such, my bet is on an all-diesel ( or potentially diesel-electric) drive for the MTA 2020.

The power of the engines can then make the vessel move with propellers (either fixed or controllable pitch), different kinds of azimuth thrusters (pods with propellers), or waterjets. Here, the point needs to be made that waterjets are not engines, do not provide power to the ship, and should not be confused with gas turbines. Instead, in the same way as propellers, they transfer the power from the engine to the water, to make the ship move. Their big benefit compared to normal screws are their higher efficiency at high speeds, superior manoeuvrability at low speed (especially when reversing), lower noise signature, and better resistance to damage. Propellers are the favoured solution amongst ships of this size, but e.g. the new Littoral Combat Ships of the US Navy are equipped with waterjets. Of these, the Independence-class features Wärtsilä waterjets while the Freedom-class is equipped with Rolls-Royce manufactured waterjets. Both of these companies have also provided waterjets for the Finnish Navy; Wärtsilä for the Rauma-class and Rolls-Royce for smaller vessels and the Hamina-class. The big question for waterjets is their use in ice, which theoretically should not be a problem, but this is so far untested in vessels of this class.

Rauma- and Hamina-class FAC’s showing of their different waterjets. To the left Rauma’s Riva Calzoni (Wärtsilä) IRC 115-waterjets and to the right Hamina’s Rolls Royce Kamewa 90SII. Source: Wikimedia Commons/MKFI.

With regards to podded solutions, these were chosen for the Finnish Border Guard’s new flagship UVL Turva, which is roughly of the same size as the new corvettes. Her propulsion is of the combined diesel-electric and diesel-type, with two azimuth pod thrusters for normal cruising and a single giant controllable pitch propeller for added speed. I personally find a podded solution less likely for a surface combatant due to the pods leaving too much of the propulsion gear sticking out far under the hull where it is susceptible to damage.

Country of Origin

The vessel itself will be built in Finland, where we traditionally have had three yards capable of producing vessels of this size. These are usually referred to as the Helsinki, Turku, and Rauma yards, due to the fact that their owners have a tendency to change far more often than their location. Of these, Helsinki is out of the equation, as it is owned by Russian interests. Rauma has traditionally been the yard of choice for major warships, but was closed by then-owner STX Finland in 2014 after the production of Turva was finished. A new company, Rauma Marine Constructions, has been formed with the aim of continuing the business. So far it seems that the state believes in the idea, as the new yard has landed a number of important overhaul and modernization contracts during its brief existence.

The Turku yard has also changed hands during the last year, going to German shipyard Meyer Werft. The aptly named Meyer Turku is specialised in cruise ships, and currently has an order book which “contains a high work load until the year 2020” according to the yard. The one thing that does point to Meyer Turku as the eventual builder of MTA 2020 is the fact that unlike the newly created RMC, Meyer is an owner with a long and solid history. Still, while the owner of Rauma might be new, the forces behind it are not, and my guess is that the vessels will be built in Rauma with RMC as the main supplier, possibly with the building of one or two being licensed to Meyer Turku if the workload there is low at the time of building.

However, what is often forgotten is that in the wake of our shipyards, a large industry producing maritime supplies is also found in Finland. The Association of Finnish Defence and Aerospace Industries (fi. PIA ry) published a three-page article on the corvette in a recent number of their paper AFDA News. The larger part of this article is common knowledge; Finland needs its navy to protect the growing trade in the Baltic Sea, we like sea mines, and so forth. The interesting part is a small info box, noting that AFDA together with Tekes, the Finnish Funding Agency for Innovation, has done a research project in 2011-2014 under the SMULAN-name. The project looked into what parts of MTA 2020 that could be supplied by domestic companies, and came to the conclusion that the engineering and building could be done here, while arms and combat systems need to be imported. The rest, including stealth technology, integration of sensors and systems, propulsion, and so forth, is found in Finland.

Old Azipod azimuth thruster manufactured by ABB in Finland, now a museum piece in Turku. Source: Wikimedia Commons/Kovako-1

Here, a small disclaimer is in place: AFDA is obviously not an independent organisation when it comes to questions like these, but has its own goals. Simply that there is a Finnish alternative does not necessarily mean it is the best one. Still, the impressive references of companies like the aforementioned Wärtsilä and Rolls-Royce points to the truth in the SMULAN-project. Rolls-Royce plc. is indeed British, but through the acquisition of Vicker’s marine division, which included classic Finnish companies Rauma-Repola, Hollming, and FF-Jet, it has a rather large presence in Finland through the national subsidiary Rolls-Royce Oy Ab, and the company is currently in the process of moving propulsion production lines (including e.g. production of the Kamewa waterjets powering the Hamina-class) from Sweden to Finland. Another fact that improves the odds for Finnish companies is the fact that the purchase of the three new mine countermeasure vessels of the Katanpää-class from Italian yard Intermarine has been less than stellar. Projects of this scale are usually encountering some teething troubles, but the fact that the third vessel of the class four years after its naming ceremony still hasn’t left Italy has not been looked kindly upon.