Azipod

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Closeup of one of USCGC Mackinaw's 3.3 MW Azipod units Mackinaw WLBB-30 Azipod thruster.jpg
Closeup of one of USCGC Mackinaw's 3.3 MW Azipod units

Azipod is a trademarked azimuth thruster pod design, a marine propulsion unit consisting of a fixed pitch propeller mounted on a steerable gondola ("pod") containing the electric motor driving the propeller, allowing ships to be more maneuverable. They were developed in Finland in the late 1980s jointly by Wärtsilä Marine, Strömberg and the Finnish National Board of Navigation. [1]

Contents

Although "Azipod" is a registered brand name, it is sometimes used as a generic trademark for podded propulsion units manufactured by other companies. [2] [3] [4] [5]

Concept

In the conventional azimuth thrusters such as Z-drive and L-drive thrusters, the propeller is driven by an electric motor or a diesel engine inside the ship's hull. The propeller is coupled to the prime mover with shafts and bevel gears that allow rotating the propeller about a vertical axis. This type of propulsion system has a long tradition throughout the 1990s and today such propulsion units are produced by a number of companies around the world. [6]

In the Azipod unit, the electric motor is mounted inside the propulsion unit and the propeller is connected directly to the motor shaft. [7] Electric power for the propulsion motor is conducted through slip rings that let the Azipod unit rotate 360 degrees about the vertical axis. [8] Because Azipod units utilize fixed-pitch propellers, [9] power is always fed through a variable-frequency drive or cycloconverter that allows speed and direction control of the propulsion motors. [10]

The pod's propeller usually faces forward because in this pulling (or tractor) configuration the propeller is more efficient due to operation in undisturbed flow. Because it can rotate around its mount axis, the pod can apply its thrust in any direction. Azimuth thrusters allow ships to be more maneuverable and enable them to travel backward nearly as efficiently as they can travel forward. In order for the full capabilities of podded propulsion units to be realized in commercial service, shiphandling training on simulators and manned models is required for the crew. [11]

The podded design typically achieved a 9% better fuel efficiency than the conventional propulsion system when it was first installed in the 1990s. In the meantime, improvements to the conventional designs have shrunk the gap to 6–8%, but on the other hand the hydrodynamic flow around the Azipod has been improved by fin retrofits and a dynamic computer optimization of the respective operating angles of the pods in multipod installations, thereby yielding overall efficiency improvements now in the range of 18%. [12]

History

Development

The first Azipod unit, installed on the Finnish fairway support vessel Seili in 1990, is now displayed at the Forum Marinum maritime museum in Turku, Finland. First Azipod.jpg
The first Azipod unit, installed on the Finnish fairway support vessel Seili in 1990, is now displayed at the Forum Marinum maritime museum in Turku, Finland.

In 1987, the Finnish National Board of Navigation made a co-operation proposal to the electrical equipment company Strömberg (later ABB) and the Finnish shipbuilder Wärtsilä Marine for the development of a new type of electric propulsion unit. [13] Prior to this, the companies had been working together for decades in the field of diesel-electric propulsion systems and in the 1980s produced the first icebreakers with alternating current propulsion motors and cycloconverters. [14]

The development of the prototype started in 1989 and the first unit was ready for installation in the following year. [15] The 1.5 MW unit, dubbed "Azipod" (short for azimuthing electric podded drive [16] ) was installed on the 1979-built Finnish fairway support vessel Seili at Hietalahti shipyard in Helsinki, Finland. After the refit, the vessel's icebreaking performance was considerably increased and she was also found out to be capable of breaking ice astern (backwards). This discovery of a new operating mode eventually led to the development of the double acting ship concept in the early 1990s. [17] [18] When Seili was refitted with new propulsion system in the 2000s, the prototype unit was donated to Forum Marinum and put on display in Turku, Finland.

Following the encouraging experiences from the prototype installation, the development of the Azipod concept continued and the next units were retrofitted on two Finnish oil tankers, Uikku and Lunni, in 1993 and 1994, respectively. Nearly eight times as powerful as the prototype, the 11.4 MW Azipod units considerably increased the icegoing ability of the vessels that were already built with independent icebreaking capability in mind. [17] Since the 1990s, the vast majority of ships capable of operating in ice without icebreaker escort have been fitted with Azipod propulsion system. [19]

The first three Azipod units were of so-called "pushing" type in which the propeller is mounted behind the gondola. In the subsequent installations, ABB adopted the more efficient "pulling" configuration similar to propeller-driven airplanes.

The world's first cruise ship fitted with Azipod propulsion units, Elation, was delivered by Kværner Masa-Yards Helsinki shipyard in the spring of 1998. [20] Even though the Azipod was initially developed for icebreaking vessels, cruise ships have become the largest group of ships by type to be fitted with Azipod propulsion system since the 1990s and the success of the electric podded propulsion units has paved the way for competitors such as the Rolls-Royce Mermaid. Among the vessels fitted with Azipod units are Royal Caribbean International's Voyager-, Freedom- and Oasis-class cruise ships, each of which held the title of the largest cruise ship in the world at the time of delivery. [19]

Another further development of the original electric podded propulsion concept is the Compact Azipod, a smaller Azipod unit introduced in the early 2000s. It is intended for smaller ships such as research vessels and yachts as well as dynamically positioned drilling rigs that may utilize up to eight such propulsors. [19] [21] The smaller Azipod Compact differs from the full-size unit by its permanent magnet synchronous motor which is directly cooled by sea water. For drilling vessels, it is also available in "pushing" configuration and can be fitted with a nozzle to increase bollard pull thrust in stationkeeping applications. [22] Unlike the full-sized Azipod units which are assembled in Finland, the Compact Azipod units are manufactured in China. [23]

During the initial years in service, some widely publicised cruise ship service disruptions with the bigger Azipod V design have occurred. [24]

The latest design, the Azipod X, incorporates these improvements, with a view to a service interval of five years, and features bearings that can be taken apart and repaired from inside the pod while the ship is harbored normally. [25] [26]

See also

Related Research Articles

<span class="mw-page-title-main">Azimuth thruster</span> Steerable propulsion pod under a watercraft

An azimuth thruster is a configuration of marine propellers placed in pods that can be rotated to any horizontal angle (azimuth), making a rudder redundant. These give ships better maneuverability than a fixed propeller and rudder system.

<span class="mw-page-title-main">Voith Schneider Propeller</span> Proprietary marine propulsion system

The Voith Schneider Propeller (VSP) is a specialized marine propulsion system (MPS) manufactured by the Voith Group based on a cyclorotor design. It is highly maneuverable, being able to change the direction of its thrust almost instantaneously. It is widely used on tugs and ferries.

<span class="mw-page-title-main">Z-drive</span> Steerable marine drive system

A Z-drive is a type of marine propulsion unit. Specifically, it is an azimuth thruster. The pod can rotate 360 degrees allowing for rapid changes in thrust direction and thus vessel direction. This eliminates the need for a conventional rudder.

MT <i>Alma</i> Aframax crude oil tanker

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<i>La Noumbi</i> Floating production storage and offloading unit operated by Perenco

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MV <i>Arcadia</i> (2004) Cruise ship

MS Arcadia is a cruise ship in the P&O Cruises fleet. The ship was built by Fincantieri at their shipyard in Marghera, Italy. At over 84,000 gross tonnage (GT), Arcadia is the second smallest of seven ships currently in service with P&O Cruises. The ship officially entered service with the company in April 2005 and was named by Dame Kelly Holmes.

<span class="mw-page-title-main">Maneuvering thruster</span> Transverse or steerable propulsion device in a watercraft

Manoeuvering thrusters are transversal propulsion devices built into, or mounted to, either the bow or stern, of a ship or boat to make it more manoeuvrable. Bow thrusters make docking easier, since they allow the captain to turn the vessel to port or starboard side, without using the main propulsion mechanism which requires some forward motion for turning; The effectiveness of a thruster is curtailed by any forward motion due to the Coandă effect. A stern thruster is of the same principle, fitted at the stern. Sufficiently large vessels often have multiple bow thrusters and stern thrusters.

<span class="mw-page-title-main">Pleuger rudder</span> Thruster assisted ships rudder

The Pleuger rudder is a power assisted ship's rudder. It creates a flow of water in the direction the rudder points powered by an auxiliary electric motor. This aids maneuverability at low speeds greatly, since it operates on a similar principle to a thruster.

An L-drive is a type of azimuth thruster where the electric motor is mounted vertically, removing the second bevel gear from the drivetrain. Azimuth thruster pods can be rotated through a full 360 degrees, allowing for rapid changes in thrust direction and eliminating the need for a conventional rudder. This form of power transmission is called a L-drive because the rotary motion has to make one right angle turn, thus looking a bit like the letter "L". This name is used to make clear the arrangement of drive is different from Z-drive.

MT <i>Indiga</i> Russian ice-strengthened tanker

MT Indiga was an ice-strengthened product tanker that sailed under the Finnish flag in 1976–2003 and under the Russian flag in 2003–2021. After her modernization in 1994 she became the second merchant ship, after her sister ship Varzuga, to be equipped with an electric azimuth thruster called Azipod.

MT <i>Varzuga</i> Russian ice-strengthened tanker

MT Varzuga was an ice-strengthened product tanker that sailed under the Finnish flag in 1977–2003 and under the Russian flag in 2003–2021. After her modernization in 1993, she became the first merchant ship to be equipped with Azipod, an electric azimuthing propulsion unit developed in Finland in the late 1980s. She was also the first non-Soviet ship to transit the Northern Sea Route.


A double acting ship is a type of icebreaking ship designed to travel forwards in open water and thin ice, but turn around and proceed astern (backwards) in heavy ice conditions. In this way, the ship can operate independently in severe ice conditions without icebreaker assistance but retain better open water performance than traditional icebreaking vessels.

MSV Botnica Estonian multipurpose icebreaker

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Arcticaborg (Арктикаборг) is an icebreaking platform supply vessel. She was previously operated by Wagenborg Kazakhstan in the Caspian Sea but was transferred to Canada in 2017 and acquired by Fathom Offshore in 2018. In 2019, she was contract to Russia for two years.

Georgiy Sedov is an icebreaking platform supply vessel operated by Rosmorport in the Sea of Azov. She was built by Kværner Masa-Yards in Helsinki, Finland, in 1998 as Antarcticaborg for Wagenborg Kazakhstan to be used in the Caspian Sea.

<i>Baltika</i> (icebreaker) Russian icebreaker with asymmetric hull

Baltika is a Russian icebreaker built by Arctech Helsinki Shipyard in Helsinki, Finland. She is the first ship ever built with an asymmetric hull that allows her to operate not only ahead and astern, but also obliquely (sideways) with a large angle of attack. In this way, the relatively small oblique icebreaker is capable of opening a wide channel in ice for large merchant ships.

<span class="mw-page-title-main">Rim-driven thruster</span> Electric propulsion unit for ships

The rim-driven thruster, also known as rim-driven propulsor/propeller is a novel type of electric propulsion unit for ships. The concept was proposed by Kort around 1940, but only became commercially practical in the early 21st century due to advances in DC motor controller technology. As of 2017, commercial models of between 500 kW and 3 MW are available from manufacturers such as Rolls-Royce, Schottel, Brunvoll, Voith, Van der Velden, etc.

<i>Polaris</i> (icebreaker) Finnish icebreaker

Polaris is a Finnish icebreaker. Built in 2016 by Arctech Helsinki Shipyard, she is the most powerful icebreaker ever to fly the Finnish flag and the first icebreaker in the world to feature environmentally friendly dual-fuel engines capable of using both low-sulfur marine diesel oil (LSMDO) and liquefied natural gas (LNG). Polaris was initially ordered by the Finnish Transport Agency, but the ownership was transferred to the state-owned icebreaker operator Arctia after delivery.

Röthelstein is an Austrian river icebreaker owned by Verbund AG. She is used to break ice and push barges on the Danube river. Built by Kværner Masa-Yards in Finland in 1995, she was the first new vessel to be fitted with Azipod propulsion units.

<i>Murmansk</i> (2015 icebreaker) Russian icebreaker

Murmansk is a Russian Project 21900M diesel-electric icebreaker. While her construction was contracted to Vyborg Shipyard in Russia, she was built at Arctech Helsinki Shipyard in Finland and delivered to Rosmorport in 2016.

References

  1. ↑ "ABB's Azipod® azimuth thruster system wins the Finnish Engineering Award and 30 000 euros". TEK. 1 December 2021. Retrieved 11 April 2023.
  2. ↑ MAO:249/18. Markkinaoikeus, 8 May 2018. Retrieved2019-02-18.
  3. ↑ Inside view: What makes QM2 go. Beyond Ships. Retrieved2014-04-26.
  4. ↑ Marine Propulsion & Auxiliary Machinery: The Journal of Ships' Engineering Systems. Riviera Maritime Media. 2005.
  5. ↑ Brian J. Cudahy (2001). The Cruise Ship Phenomenon in North America. Cornell Maritime Press. pp. 53–. ISBN   978-0-87033-529-7.
  6. ↑ Tammiaho, Erkki. "Ruoripotkurilaitteiden liiketoiminta Suomessa, TEKES, 258/2009" (in Finnish). Archived from the original (PDF) on 2010-12-08. Retrieved 2013-12-05.
  7. ↑ Pakaste, Risto; et al. (February 1999). "Experience with Azipod propulsion systems on board marine vessels" (PDF). Archived from the original (PDF) on 2014-03-27. Retrieved 2012-12-25.
  8. ↑ Society of Naval Architects and Marine Engineers (U.S.) (1994). Transactions – The Society of Naval Architects and Marine Engineers. Society of Naval Architects and Marine Engineers. ISBN   978-0939773152.
  9. ↑ Lakeside Publishing Co. (2002). Cruise Travel. Lakeside Publishing Co. pp. 42–. ISSN   0199-5111.
  10. ↑ Mukund R. Patel (2012). Shipboard Propulsion, Power Electronics, and Ocean Energy. CRC Press. pp. 188–. ISBN   978-1439888506.
  11. ↑ Port Revel Pod Shiphandling course
  12. ↑ "Azipod propulsion drives take the next step". Skipsrevyen. March 2011. Archived from the original on 2013-10-02. Retrieved 2013-09-24.
  13. ↑ Hepo-oja, Anssi; Mäki-Kuutti, Viktor (2012). Mekaanisen ja sähköisen propulsiojärjestelmän esittely (PDF). Satakunta University of Applied Sciences.
  14. ↑ Cycloconverters for the new icebreaker from Kymmene-Strömberg. Navigator 1985.
  15. ↑ 1. Dynamosta Azipodiin – vuosikymmenien kokemukset jäänmurtajista. ABB Group. Retrieved2013-10-05.
  16. ↑ ABB-teknologiat: Azipod®-propulsiojärjestelmät. ABB. Retrieved2016-02-12.
  17. 1 2 Juurmaa, K et al.: The development of the new double acting ships for ice operation. Kvaerner Masa-Yards Arctic Technology, 2001 Archived 2012-03-03 at the Wayback Machine and 2002 Archived 2012-09-04 at the Wayback Machine .
  18. ↑ Juurmaa, K et al.: New ice breaking tanker concept for the arctic (DAT) Archived 2012-03-03 at the Wayback Machine . Kvaerner Masa-Yards Arctic Technology, 1995.
  19. 1 2 3 References – Propulsion Products Archived 2014-06-11 at the Wayback Machine . ABB. Retrieved2014-04-26.
  20. ↑ 6.11. Azipod ® propulsion Archived 2014-04-26 at the Wayback Machine . ABB. Retrieved2014-04-26.
  21. ↑ Compact Azipod Archived 2014-04-26 at the Wayback Machine . ABB. Retrieved2014-04-26.
  22. ↑ Azipod C Archived February 24, 2014, at the Wayback Machine . ABB. Retrieved2014-04-26.
  23. ↑ ABB Propulsion Products for Main Propulsion and Thrusters Archived February 25, 2014, at the Wayback Machine . ABB, June 2012. Retrieved2014-04-26.
  24. ↑ Fredrickson, Tom (2000-07-22). "Carnival's Paradise Coming To Yard For Repairs". Newport News, Virginia: Daily Press . Retrieved 2013-09-24.
  25. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2013-12-30. Retrieved 2012-12-27.{{cite web}}: CS1 maint: archived copy as title (link)
  26. ↑ "Propulsion Systems by ABB Marine". Wplgroup.com. 2012-02-13. Archived from the original on 2013-12-30. Retrieved 2013-09-24.
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