Introduction
Water transport is known to be the most energy efficient, environmentally friendly and economic mode of transport. In Central Europe, the rivers are widely used to transport cargo and passengers on the waterways to get traffic away for the busy roads and railways. Similar opportunities exist also to utilise the Finnish lakes and rivers, but the opportunities have not been used so far. For example, on the area of lake Saimaa only about 10 % of the total cargo volumes of 20-30 tons are transported by waterways. In addition, the opportunities to link the Finnish lakes and rivers with the those on the Russian side have not been realised.
Since 2018, INFUTURE (Future Potential for Inland Waterways) project has been evaluating new attractive business opportunities and possibilities in the frames of Inland Waterways with a joint venture between some key partners form Finland and Russia. A number of reports have been published about the possible cargo volumes and fairway developments on the project website (> INFUTURE-project).
This presentation concentrates on the development of possible new ship concepts for the future cargo transport as done by the Finnish partners of the consortium.
Waterway Dimensions
Currently the fleet of ships transporting cargo between Saimaa and Russia is limited in main dimensions by the restraints set upon them by the different waterways. These limitations can be seen summarised in Table 1. As can be seen from Table 1, the Saimaa channel will be lengthened 10 m and deepened 0.1 m in near future. In addition, the navigational season will be extended to 11 months per year.
The vessels moving today between Saimaa and the Russian inland waterways are quite old. Furthermore, most of the ships operating in Saimaa and the Russian inland waterways are powered by diesel engines, which make them noncompliant with current emission targets. These factors coupled with the planned increase in the size of the Saimaa locks has created a need for new ship concepts for the transport of cargo in the inland waterways between Saimaa and Russia.
Developed new concepts
Two vessel concept designs have been generated in co-operation between Aalto University and Aker Arctic for the INFUTURE project. Both have been designed with the expanded Saimaa canal locks in mind. Both are of similar size and capable of handling a variety of general cargo. The vessels have a service speed of 11.5 knots and are able to run on biofuel. They come equipped with lift away hatchcovers, movable tweendecks and bulkheads, and an option for gantry cranes. The main difference between them is in their ice capability, and the changes that this necessitates as explained next.
Concept 1, 4000 DWT General Cargo
The first vessel concept is designed to have the maximum cargo tonnage possible within the size restraints of the new Saimaa locks. This translates to 4000 DWT in the Baltic, 3020 DWT in the Saimaa canal, and finally 2250 DWT in the Russian inland waterways. It has a traditional hull form and is equipped with a single 2.8 m diameter fixed pitch propeller. It has a Finnish-Swedish ice class of 1A and is not intended for independent operation during winter. Its main specifications can be seen in Table 2. A concept image can be seen in Figures 1-2.
Table 2. Main specifications of 4000 DWT General Cargo concept design for Saimaa and Volga-Balt region.
Concept 2, 3560 DWT General Cargo
The second vessel concept is designed to be a double acting ship able to operate independently in ice. Its ice capability is 2 knots in 0.6 m thick ice whilst traveling stern first and it has a Finnish Swedish ice class of 1A Super. In order to be able to break ice stern first, it has been equipped with a 2.8 m diameter, mechanically driven azimuthing thruster. These ice capabilities come at the cost of reduced cargo capacity. This concept has a cargo capacity is 3560 DWT in the Baltic, 2640 DWT in the Saimaa canal, and finally 1890 DWT in the Russian inland waterways. Its main specifications can be seen in Table3 and few images on Figure 2.
Table 3. Main specifications of 3560 DWT General Cargo concept design for Saimaa and Volga-Balt region.
Figure 1. Images of the 4000 DWT ship
Figure 2. Images of the 3560 DWT ship
The current vessels operating in between the Finnish Lake Saimaa and Russian Volgo-Balt regions are primarily designed to transport dry cargo (either bulk cargo or timber).
General Cargo Vessel for Bulk, Containers and Project Cargo
The INFUTURE concepts have been designed as general cargo vessels, capable of transporting bulk cargo, containers and project cargo. Therefore, these vessels allow for a more varied business model. With vessels rated with high Finnish-Swedish Ice Classes this enable the navigation season up to 11 months. Furthermore, with the 3560 DWT concept being capable of breaking up to 0.6 m ice stern first, it would be able to operate independently for most of the year. This makes it a first of its kind. Both these concepts would therefore be able to extend the season significantly when compared with the existing vessels.
Lastly, the existing vessels have a problem with environmental regulations. The existing fleet primarily runs on fossil based fuels such as diesel, and consequently is unable to meet ever tightening environmental legislations. Furthermore, the IMO Ballast Water Management Convention (BWM Convention) is coming into effect in 2022, and it has been argued that making the modifications required by this convention is not financially worthwhile for ships as old as the ones operating between Saimaa and Russia. The proposed INFUTURE concepts would alleviate both these problems. Biofuels have a huge potential to reduce carbon emissions and so both the proposed concepts would be very low emission when compared to the currently operational vessels. In addition, they would come equipped with the systems required to comply with the IMO BWM Convention and prevent the transportation of foreign species.
Model Scale Testing of the New Concepts
To validate the concept design of the new concepts, model-scale ice tests were conducted in the Aalto Ice Tank in March and April 2021. The tests included level ice, restricting channels, pre-sawn ice and ice-free channels. In all the tests the total resistance experienced by the model was measured.
The aim of these tests was to estimate the ice resistance of the INFUTURE concept in varying ice conditions. They were performed using the procedure described in ITTC 7.5-02-04-02.1. The hull form in question operates with the double acting principal. The scaling factor for the tests were 16.82, so the model total length is 5.5 m. The independent version of the concepts was tested.
Aalto Ice Tank is a 40 m × 40 m basin with cooling units at both ends. The ice is created by spraying layers of fine mist over a period of several hours. The water used is chemically doped with ethanol to attain the desired mechanical properties. In total, four sets of tests were conducted using four different ice sheets. Since the tested hull form is a double acting hull, all tests were conducted stern first.
The first and second set of tests were performed on the 25th and 30th of March 2021 respectively. These adopt strong ice with flexural strength 800kPa to represent lake ice. The targeting thicknesses are 40cm and 60cm. The third and fourth tests were performed on the 7th and 13th of April 2021. These adopt weaker ice with flexural strength 500kPa to represent sea ice. The targeting thicknesses are also 40cm and 60cm.
The detail analysis of the tests is still ongoing, but the preliminary analysis has indicated that the ship concept will fullfill the requirement of breaking 0.6 m ice with 2 kn while travelling stern first in sea ice. In lake ice where ice is stronger, the ship can break 0.5m ice with 2kn. Overall, the icebreaking capability of the ship enables the ship to go through ice-covered water in the Saimaa lake most of its operational time independent. Figure 3 show some images taken during the model scale test.
Conclusions
Two new, environmentally friendly multipurpose ship concepts for the lake Saimaa area have between developed taken into account the new dimensions of the Saimaa-channel. Other is for independent navigation with the double acting concept i.e. going astern in ice and the other is aimed to be assisted by icebreaker during wintertime. The double-acting concept has been tested also in Aalto ice tank, and the tests have indicated that the ship concept will fullfill the requirement of breaking 0.6 m ice with 2 kn while travelling astern.
Figure 3. Images of the 3560 DWT ship in Aalto ice tank.
Authors: Professor Pentti Kujala and Li Fang, Postdoctoral Researcher, Aalto University, Helsinki, Finland.
The Second Part of the Article: How Reliable Are Numerical Simulation Models to Predict Ship Performance in Lake Ice? > ARTICLE
This study has been conducted in the frames of the INFUTURE, Future Potential of Inland Waterways project, funded from the South-East Finland – Russia CBC 2014–2020 programme. The total budget for the project is EUR 1,251,538.