New propulsion order for a newbuild icebreaker

Steerprop has received a new order for two 2.5 MW SP 60 PULL ARC propulsors to be delivered to a newbuild icebreaking vessel. This strengthens Steerprop’s position as a global supplier of propulsors of this size that can operate in extreme arctic conditions.

As the Arctic summer sea ice continues to melt, arctic routes are experiencing substantial increases in traffic. Although transiting via the arctic waters may cut as much as 50% off the days at sea, it also adds more risk of uncertainty to the route. With the ever increasing number of shipowners investing in vessels capable of navigating through ice, Steerprop’s 2.5 MW PULL ARC propulsors are gaining popularity for vessels that need free-running efficiency and ice-milling capabilities in icy waters.

Experience matters

“We were selected to deliver this special solution to a newbuild icebreaker, thanks to our long-term experience in delivering robust propulsion technology to icebreaking vessels,” says Tapio Aho, Sales Manager at Steerprop.

To date, Steerprop has delivered over 85 ice-class units, most of them now operating in some of the harshest arctic conditions. “This order strengthens our position in the market when it comes to providing demanding icebreaker applications,” he continues. “And we hope that this will open up other new similar opportunities in this niche business sector.”

Rugged throughout

The Steerprop SP 60 PULL ARC propulsion units have been designed and built with multiple layers of redundancies and fail-safes for safe, reliable and efficient operations in the most extreme operating conditions. These advanced propulsors combine ice-breaking power with the reliability of mechanical construction and the accurate controls of modern automation technology.  

This special azimuth propulsor technology provides outstanding performance in all kinds of ice management operations. The ability to direct the vectored thrust from the propeller in a full 360 degrees allows the vessel to widen fairways, blow ice ridges or free arctic installations from the ice.

For more information, please contact:
Tapio Aho, Sales Manager, Steerprop, Tel. +358 40 727 1203

True power train optimization is holistic

Optimizing how something as powerful as vessels use of energy is a huge endeavor. Luckily, there are ways that support your work to achieve maximum efficiency, starting with the propeller.

What exactly leads to hydrodynamic propulsion efficiency? Instead of trying to optimize the individual components within a power train, our approach at Steerprop is to consider all critical components in a holistic manner. This includes frequency converters, generators and other power consumers. We also look at the cooling and auxiliary equipment, that add to the total cost, but are often forgotten.

We start with the propeller. This is where mechanical energy is converted to thrust to propel the vessel. If the propeller is inefficient – or the best propulsion efficiency is not achieved for every type of vessel operation – the rest of the power train needs to be overdimensioned to transmit the power required for different propulsion needs.

When the power train is overdimensioned, it is constantly operating in partial load mode. This means the best possible efficiency cannot be achieved through the power train.

Figure 1 shows how power train losses are born. By increasing efficiency on the right side, the losses on the left become automatically smaller as you move from right to left.

Figure 1. The basis of Steerprop’s efficiency doctrine: fuel to thrust chart.

To help shipowners and design offices analyze the efficiency of their entire drive train and reach the best possible performance at sea, we have created an approach that considers the holistic power train.

Together with partners in our ecosystem, we can deliver a complete power train that encompasses the propulsor drive solution, our propulsor and permanent magnet generators for efficient power distribution. With this solution, the vessel’s electrical power is created with permanent magnet variable-speed generators connected via inverters to a common DC link. The generators and power battery bank continuously operate in parallel. Energy storage systems, such as a battery, can be used for peak-shaving functionality. Other power sources can also be included.

When combining these with a careful design and thoughtful decision on the choice of propulsor, the efficiency of the whole propulsion line can improve significantly.

This energy optimization balancing act, when done right provides both short- and long-term benefits that include more profitability though greater hydrodynamic efficiency, less chance of disruptions such as surges and blackouts, lower and more predictable maintenance costs.

What’s more, an optimized solution offers the flexibility to use power input from different sources. This enables vessels to be designed using alternative power sources to reduce their carbon footprint and meet the increasingly more stringent CO2 regulations. 

About the author:

Juho Rekola works as Chief Design Engineer at Steerprop. He has been involved in marine technology from the beginning of his career, focusing on high-efficiency solutions for the industry.

Today, he works closely with electrical and hybrid power to bring the marine industry the best solutions for tackling climate change and rising operational costs. He feels that optimizing the entire power train holistically is the best way to achieve maximum efficiency.

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Successful project management propels us forward

The key to successful project management is simple: we always need to deliver on time and without any extra costs. This is critical in each project.

Over the years, Steerprop has built up a solid reputation among our customers for excellent project management, specifically for these reasons. We’ve focused on setting the bar high for ourselves by choosing responsible project managers who have excellent communication skills, strong technical backgrounds and are outstanding team players.

One thing that makes our project management style unique is that we take responsibility for all aspects of our projects, including the classification process. While this means more time and responsibility for us, it also gives us better control over the projects we work with. As a result, our customers benefit considerably. That’s because of our wider commitment to ensuring each project reaches a successful completion and gives them exactly what they asked for.

We use various programs to track each project’s progress. All documentation, including any agreed-upon changes, are saved online in one unified place. This allows everyone involved in the project instant access to detailed information at any time.

We work hard to keep our projects on course and make sure that our suppliers deliver the required components both on time and up to quality standards. If any component delivery is late, there may be project delays. This is when communication with our customers is highly important.

Our style is such that we are always honest with our customers. Should anything steer our projects off course, we let them know immediately. Steerprop has highly skilled personnel who are committed to putting in additional hours to solve any problems that may arise.

For any problem we run into, I know there’s always a solution. Sometimes, it is easy to find. Other times, it can be challenging. Regardless, we just closely work with every department, supplier and customer to make sure our fast communication and flexibility result in successful project delivery.

We also make sure to ask our customers for feedback on meeting their expectations and how well they feel their expectations were met. This is how we can single out ways to improve on our delivery. At the end of the day, we want our customers to be happy. Pleasingly, our proactive management style has received good feedback. Recently, the manager of a Russian shipyard asked for a face-to-face meeting to express his satisfaction with an ongoing project. 

Another – and possibly most important – component to Steerprop’s success in project management is our highly skilled and talented personnel. We believe in motivating each other through humor and a positive attitude. This, in turn, allows us to give our best to our customers, helping them complete their projects on time and within budget.

We feel this is something we always do well – because it’s simply the Steerprop way.

About the author:

Juha Jusi has worked as Project Manager at Steerprop for nearly two years. Before starting at the company, he was involved in project management in various fields for many years. 

In his opinion, successful project management requires proactive communications, complete honesty and outstanding teamwork. These are some of the main reasons Steerprop has earned its unrivaled reputation for excellent project management among customers worldwide.

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Do you know the basic dimensioning principles for arctic propulsors?

Understanding how ice loads affect vessels is critical when designing and dimensioning propulsors that provide top performance and fuel efficiency, while not harming the fragile arctic environment.

How to best dimension every propulsor depends on the requirements of each ice class. So to ensure the best results when designing each propulsor, it is important to check all classification requirements for that vessel. The ice class rules for Arctic Vessels in most class societies follow the IACS Unified Requirements for Polar Ships, with PC 1 being the hardest ice and PC 7 being the weakest – old ice , in general, being harder than new.

The nature of the ice, and how much pressure is required to break through, affects the load, so it is vital to understand how ice load affects the propulsor under the water. The class rules dictate how to dimension the housing to break through different ice load magnitudes.

For example, the longitudinal load is factored differently than the transversal load, which is more critical with respect to the propulsor design. Still, both must account for the load of a consolidated ice sheet that slides down the hull and impacts the propulsor. Especially with azimuth thrusters, the transversal load can play a major role. Still, all directional ice loads and magnitudes need to be considered as they hit the propulsor from different sides while the vessel cuts through ice.

When dimensioning arctic propulsors, Steerprop analyzes the impact of ice loads on the slewing ring dimensioning – the hull attachment inside the ship’s hull, with bolts dimensioned to provide the strength of the housing that withstands the ice loads.

For most ice classes, Steerprop recommends stainless steel propellers, but bronze propellers are also available for lighter ice classes. Blade scantlings are calculated according to class rules. The entire propeller can be delivered as a monoblock or built with blades bolted on, which are easier to replace with a spare blade, even underwater at sea, rather than changing an entire propeller.

Pushing and pulling have traditionally been the preferred propulsor type, but recently Steerprop’s contra-rotating propulsion (CRP) technology has been gaining traction with Arctic expedition cruise vessels. Electric steering combined with CRP works well, in particular for ice classes, and is more energy efficient. In addition, it is silent.

Furthermore, our pollution-free sealing solution for the severe vibration conditions caused by operating in ice has proven effective through experience.

Each ice class affects not only the final propeller design and configuration but also its power transmission gear design and steering. Steerprop uses a unique gear transmission design with the proper and effective load-carrying contact area and pattern that can maintain the safety margin for any unexpected load.

Every Steerprop propulsor also comes with high-quality roller bearings for the very best performance. To maintain consistent quality, the company has worked with only two or three top-flight bearing manufacturers over the years.

The most important outcome is to be able to ensure that the vessel can handle even unexpected loads and safely make it through the ice, even if the propulsor is damaged.

That’s why Steerprop uses computerized ice simulations to take the entire line into consideration, including the torsional vibrations from the whole system. We then provide our complete analysis of the forces to the ship design house or shipyard to further calculate the hull strength needed.

Ultimately, the classification societies set the rules. But it is up to us to calculate, simulate and formulate how much tension and deformation would be allowable at each point in the propulsor for a safe voyage above and beyond the rules, in the actual arctic marine environment.

Our mission is to give modern-day vessels the ability to venture more efficiently and safely into the icy frontier.

About the author:

Olli Knihti, graduated as a B. Sc. of Mechanical Engineering, from the Porin Teknillinen Oppilaitos in 1985. 

Olli started his career at the maritime industry in 1986 and has worked at Steerprop Ltd. since the year 2001. His responsibilities have been in project, warranty and Sales. 

In recent years Olli has been involved in the development of Steerprop product line, including the demanding arctic units for the world´s harshest environment.

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Remontowa W-series

New-generation Steerprop propulsion units for Polish Remontowa Shipyard being constructed

Two new multipurpose vessels, built by Remontowa Shipbuilding using Steerprop W series propulsion units, are now actively being constructed.

The project got its official start in March 2018, when the contract for construction and delivery was signed between Remontowa Shipbuilding SA and Szczecin Maritime Authority. Then, in June 2018, Steerprop became involved in the project. The company was contracted to supply two propulsion unit ship sets, each including a pair of Steerprop SP 25 WD propulsion units with a control system.

First in many ways

The Steerprop SP 25 W D type of propulsion units are the first in our new ‘workboat series’. The SP 25 W D unit’s lower part housing part is made of cast steel, compared to the previous Steerprop SP 25 D housing of separate bent and welded steel parts. Also, some other SP 25 W D unit structures, such as nozzles, feature improved designs compared to the traditional SP 25 D.

These are the first Steerprop products to receive PRS (Polish Register of Shipping) classification. Furthermore, since the class notation for the vessels will be PRS L1 ice class, this will be a new vessel category for PRS.

Advanced propulsion for excellent performance

Thanks to a flexible diesel-electric propulsion system, the 60-meter-long vessels will feature excellent maneuverability and dynamic positioning performance. In addition, with a deadweight capacity of 350 tons, they can achieve a solid bollard pull of 40 tons at a speed of 15 knots. Additionally, sustainability built into the propulsion system’s design will lower fuel consumption and corresponding emissions.

The delivery of the first propulsion set to Remontowa’s shipyard in Gdansk, Poland, is scheduled for early spring 2019. The second set will be delivered in summer later the same year. Both vessels are expected to be ready for service by June 2020.

Multipurpose all around – year round

The new vessels will be used for key statutory tasks for Poland’s Maritime Authorities in the ports of Szczecin and Gdynia in Poland, replacing two aging buoy tenders – Planeta and Zodiak – in use since 1982.

Their service will mainly include inspection, maintenance, transportation and replacement of navigational buoys. However, the vessels will also be fitted for hydrographic tasks, such as depth measurement, data processing and map amendment. And in case of emergencies at sea, they will be capable of emergency response, including towing operations, oil spill recovery, firefighting and other search-and-rescue tasks.

To further enhance their year-round buoy tender capabilities, both of them will feature high-impact icebreaking power, therefore making them capable of efficient ice management operations in the wintertime. With the advanced design and robust mechanical construction of their propulsion systems, icebreaking endurance will be built-in.

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Propulsion through the years

The propulsion business has experienced amazing innovations over the past several decades, and Aarno Niemi, Automation Manager at Steerprop, has seen it all. From design changes to business communications, technology is leading the shift. Niemi predicts one of the biggest changes is environmental friendliness.

Aarno Niemi joined the propulsion business in 1980 when technology was new in propulsion. He started with electric drives for locomotives, working on a project with the first megawatt-size frequency converter in the world.

He first worked in the marine business with deck machinery, when controls were simpler but unexploited. Niemi has seen changes in materials, calculations, knowledge and design tools, which now enable our company to design ultra-efficient propulsors for big and demanding vessels. Through technology development and new software over the past few decades, the business and design of propulsion systems have made great strides and opened up room for even more innovation in the marine market.

When Niemi first got into propulsion design in 1985, the controls were only manual, mechanical and pneumatic. There was no software. Over the years, the design tools have changed significantly. “Some time at the end of the 80s came electric controllers. They were in-house made electronic cards. At that time came the first processors to make the programs,” states Niemi.

In the late 80s, our company got its first CAD system, which Niemi explains was very straightforward to use. Since then, CAD system development has exploded onto the market, and we have seen great success in further simplifying the design process. The copying machine became another important tool to speed up design time.

Following this development was an active period of multiple changes in the marine market at the end of the 90s. We designed the first ice-breaker-class azimuth propulsor during this time, which was originally more popular for tug and workboats. As these propulsors became more reliable and efficient, cruise ships started using them. “That was the start of the new era of propulsor systems,” claims Niemi.

The next big change was the introduction of the first high-power PLCs in the early 2000s. The mathematics inside the PLC made them economically ideal for reliability and ease of use. It was simple technology and became popular because of the affordable price. Mechanical thrusters further helped the entire market to continue to thrive.

Throughout his many years in the business, Niemi has also seen big changes in the way communications have evolved in the marine market. Communication became more and more efficient throughout his career. In the beginning, all communications happened by writing letters, taking about three weeks to send and receive client requests. After telex and fax technologies were used more commonly in the late 80s, business communications started to speed up.

As the use of technology increased in propulsor design, it also helped improve communications. We now have Skype and email to communicate on a regular basis from remote locations. Personal presence is not as necessary as it was in the beginning of Niemi’s career, so communication is now much more productive.

During his decades-long career, Niemi has seen patterns of volatility within the marine market. Nearly every ten years he has noticed a market slump, with the biggest one in 2008.

What has remained constant, though, is the increase in propulsor efficiency over the years, which will also lead to big changes in the future. Niemi is convinced that the biggest thing coming is the green side of the business. Adding batteries and having vessels run on LNG is improving environmental friendliness within the marine market.

Advanced machinery, coupled with the use of electrical, hydrogen and battery-powered vessels, is encouraging the move to go green. This combination offers unmatched reliability and efficiency, as well as cuts service and fuel consumption costs.

Niemi predicts the next five to ten years will show even bigger changes, especially when it comes to the use of electric motors and permanent magnet motors within the company, which are the next thing on the horizon for us at Steerprop. These motors can be installed inside a vessel’s hull, which cuts maintenance costs.

The combination of these two technologies will propel us into the next big wave of change in the marine market and help us continue to pioneer the industry.


About the author:

Aarno Niemi is recently retired Senior Automation Manager of Steerprop. Aarno received M. Sc. degree in electrical engineering from the Helsinki University of Technology in 1981 and has worked in marine industry for over 30 years. In the recent years he has been involved in development of high power CRP (Contra-Rotating Propellers) propulsion units and superior azimuth propulsor with integrated permanent magnet (PM) motor.

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