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.