About Winmos III

Project goals

The European Union’s northernmost waters are covered by ice every winter, affecting maritime transports in the area. Modern logistic standards require predictability for merchant shipping, all year round, and a functioning winter navigation system is essential. The increasing number and size of vessels navigating in the Baltic Sea and new regulations for protection of the environment are impacting the winter navigation system’s design and capacity; for these reasons the winter navigation system must continuously be adapted to the changes in the maritime traffic pattern.

Winter Navigation Motorways of the Sea III (WINMOS III) aims to ensure safe and reliable winter traffic in a cost-efficient and environmentally sustainable way by developing, modernizing, and safeguarding the winter navigation system and ensuring sufficient icebreaking capacity. It will also enhance and deepen the co-operation between Estonia, Finland, and Sweden in a continued spirit of the Memorandum of Understanding (MoS) of 2015 concerning a common optimal icebreaking service level and capacity for upcoming needs.

Presented as a set of work packages, WINMOS III is a continuation of previous co-funded projects WINMOS and WINMOS II.

WINMOS III work packages focus on the following:

  • Building a large icebreaker to replace an old, existing icebreaker in Sweden to meet future needs of icebreaking capacity arising from the changed transport conditions, environmental performance, and defence capacity.
  • Investigating the need for a smaller icebreaker in partner countries, for potential replacement of the outgoing icebreakers, by doing a design study and concept development.
  • Further development of the joint Swedish and Finnish icebreaking management system, IBNet, to enhance redundancy and security.
  • Development of simulation models for ice conditions and icebreakers, as well as new simulator bridges for training to maintain unique skills of the icebreaker navigators.
  • Development of an ice field dynamics model, study on merchant fleet ice performance and suitability for icebreaker assistance and studies on icebreaker fleet composition of the future. This also includes studies of how marine wind power affects sea navigation.


Ice extension

Debate on global warming is continuously ongoing and some people think that, there will be no ice in the Baltic Sea in the future. It is therefore important to underline the fact that sea ice is expected to occur during the foreseeable future and will not disappear within many generations. Long periods with mild winters have happened before, e.g. between 1930 and 1940.

It is impossible to forecast ice extension for the coming years and therefore there must always be preparedness for severe winters. It is also very important to bear in mind that winters with lesser ice coverage are not easier from merchant vessels’ perspective. During these winters the winds are typically stronger, causing heavy ridging, and pressurized and drifting icefields. Most often these are either impossible or at least not safe for the merchant vessels to pass through without icebreaker assistance, hence making icebreaking a necessity in the region even during mild winters.

Ice coverage in the Baltic Sea varies between winters. During severe winters even the Danish straights freeze. The different ice extensions between mild, average, and severe winters are presented in the picture below.

Ice extension map

Costs of icebreaking services

The annual cost of icebreaking services depends on how difficult the winter is but during an average winter the cost of icebreaking in the Baltic Sea for Sweden, Finland and Estonia is about 110-120 M€. The cost of the whole winter navigation is much greater. Icebreakers’ operational season is usually between December and May but during a severe winter it can start as early as October.

Modern logistic standards require predictability in the transport system, all year round, why the winter navigation system must continuously be developed and meet the trading countries’ requirements. More efficient, economical, and environmentally friendly transportation is needed due to increasing traffic volumes and demands for sustainable development with more demanding environmental laws. It is also important to continue the education on how to work and operate in cold icy conditions.



The implementation period of the WINMOS III project spans from February 2023 until December 2027. The budget of the whole project is 60 M€ and the project is co-funded by EU CEF.