Keywords

1 Introduction

Inland waterway transport (IWT) is an environmentally friendly transport mode which is promoted to achieve the goal of the 2019 announced European Green Deal to reduce 90% of the transport related emissions until 2050 (European Commission 2019). IWT has, besides its eco-friendliness, other advantages such as minimal external costs and free capacities (Fastenbauer et al. 2019). To increase the share of inland navigation on the Danube and to promote a modal shift from road to IWT it is crucial to foster container transport. Until today, container transport on the Danube is limited and by far not as developed as on the Rhine. Containers have a lower relative density than bulk goods and can therefore navigate economically viable even during low water conditions. Moreover, the transport of containers allows new market opportunities for IWT on the Danube to meet the 50% increase goal of transport volume on IWT as announced in the Green Deal. (van Dorsser et al. 2020, CCNR 2020). In Europe 45 ‘standard high cube containers are highly relevant for the hinterland freight transport, in particular for multimodal transport chains, as they are broader than 40’ standard containers. This width of 2.44 m allows a better utilization of the containers being loaded with standard euro pallets. Standard euro pallets are mostly used as a packing aid in European freight transport (Gronalt et al. 2010).

The aim of this paper is to develop and evaluate new design options for container barges, i.e. unmotorized vessels, on the Danube for an optimized hinterland freight transport in Europe. The following research questions (RQ) guides this paper: RQ: Which barge designs are suitable for carrying 45’ standard high cube containers on the Danube between Enns/Austria and Giurgiu/Romania?

2 Methodology

For the development and evaluation of new design options for barges carrying 45’ standard high cube containers we used a four-step approach. First, a data collection was conducted. We collected data about locks, bridges, and ports along the Rhine-Main-Danube-Corridor. This data was subsequently processed through a large-scale desktop and literature research. Second, we agreed on a scenario based on the business case of our partner Nothegger by defining the waterway and the type of goods the barge should serve. Third, we analyzed the existing barge options for container transport on the Danube and subsequently designed new barges, which are able to navigate safely and economically viable carrying 45’ high-cube containers. All the six identified design options were finally visualized using the Naval Architecture software CAD. Fourth, we further analyzed and evaluated the identified design options for barges regarding their stability, required sight lines and possible construction materials as well as the nautical factors draught and air draught.

3 Findings and Discussion

3.1 Predefinitions

Based on the requirements of our business case for Nothegger, we agreed to design the barge options for the Danube River on the stretch between Enns in Austria and Giurgiu in Romania. Furthermore, the barges are designed to fit for carrying 45’ standard high cube containers. 45’ standard high cube containers are generally used in intermodal hinterland transport in Europe. The unique characteristic of these containers is that the size of the containers is adapted to the size of standard Euro pallets (dimensions: 120 cm × 80 cm). With the dimension of the container (13.56 m × 2.44 m × 2.7 m) euro pallets fit better in the container and therefore, increase their utilization. The reason for choosing container barges for intermodal hinterland transport is, that intermodal transport must be promoted, particularly on the Danube, since there hardly takes place container transport nowadays.

3.2 Designed Barge Options

To design new barge options, we started with existing barge design options for containers transport used on the Danube. Currently used barge designs on the Danube are the barges Europa 2b and Europa 3a, shown in Fig. 1. The new six barges were designed to allow a safe and economically viable transport of 45’ high-cube containers on the Danube. Figure 1 presents the new design options for barges including the length, the breadth, the lightship displacement and the number of 45’ standard high cube containers, which can be carried.

Each barge design can carry two or three layers of containers, which is the maximum on the Danube since there is insufficient bridge height on the Danube to carry more than three layers. A minimum of 24 45’ high-cube containers (i.e. Barge Europa 2b in two layers) and a maximum of 90 45’ high-cube containers (i.e. Barge iw-net – Container transverse v2 in three layers) can be carried using one barge. The barges differ in length and breadth, with each barge fitting into the maximum possible length and breadth of barges on the Danube according to the maximum fairway width and lock sizes. While the barge designs in general allow integration into usual pushed convoy formations with two barges side-by side, this is not the case for the broader IW-NET – Containers transverse barge type with a view to lock sizes available in particular on the upper Danube.

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Fig. 1.
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Result: overview of the barge design options

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3.3 Further Analysis of the Barge Design Options

The barge designs were further evaluated regarding their sight lines and stability resulting in several barge options being not feasible for transportation. Furthermore, different construction materials were compared and discussed.

The stability of barges with two layers of containers is basically given. Considering the barges with three container layers, the stability of three barge types is severely limited: for the “Barge iw-net - 3 units abreast” (Project ID 003), “Barge iw-net - 3 units abreast long” (Project ID 006) and “Barge iw-net - NEWS Evolution long” (Project ID 007) three layers of containers are limited to the transport of empty containers. Therefore, the barges with the Project ID 003, 006 and 007 cannot be used to transport loaded containers in three layers in most cases. However, the stability has only been assessed for pre-defined standard loading conditions and is always depending on the individual loading conditions of the barge. The stability of the barges was assessed against the requirements of Chapter 27 of ES-TRIN 2021 for non-secured containers. Figure 2 shows the design options and their stability in different loading conditions (CESNI 2021).

Fig. 2.
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Result of the stability assessment

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Regarding the sight lines, an elevating wheelhouse on the push-boat is necessary if more than one container layer is transported. In general, transportation with barges loaded with two container layers is feasible. Transportation with barges stacked with three container layers is restricted to loaded containers, as empty containers are too lightweight. Therefore, the barges do not immerse deep enough to allow an acceptable sight line. The assessment of sight lines was conducted against the requirements of Article 1.07 of CEVNI (United Nations Economic Commission for Europe 2021). Figure 3 shows the design options regarding the sight lines in different loading conditions.

Fig. 3.
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Results of sight lines assessment

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As construction materials for the barges we evaluated shipbuilding steel, aluminum and composites such as carbon. Composites are technically not feasible for the construction of cargo vessels in inland navigation, leading to an exclusion of composites for further evaluation. Shipbuilding steel succeeded as the most appropriate and affordable material. A major disadvantage of shipbuilding steel is its weight. In fact, shipbuilding steel is relatively heavy leading to unfavorable conditions for low water levels. Aluminum offers the advantage to be lightweight leading to a lower draught. Indeed, aluminum is less ductile as well as highly expensive in building and repair. The latest developments of the prices for steel and aluminum represent a challenge for the shipbuilding sector and the financing of future new barges.

A major finding is that all six design options are feasible for the transportation of containers during fluctuating water conditions. The six barge designs differ on the one hand in its size (i.e. in length or breadth) and on the other hand in the used construction material. It is hardly possible to determine the best suitable barge design for the transport of 45’ standard high cube containers from Enns to Giurgiu, since this decision depends on the specific transport situation and requirements of the business case.

4 Conclusions

In our paper, we developed six barge designs which are suitable to carry 45’ standard high cube containers on the Danube, specifically on the stretch between Enns/Austria and Giurgiu/Romania. The six barge designs differ in their size and their container carrying capacity. Each of the barges is able to carry between 24 and 90 45’ standard high cube containers. Furthermore, we investigated each option regarding their stability and found, that three designs have major limitations if they are stacked in three layers. Considering the sightlines, it was found, that all barge options, loaded with more than one layer of containers need an elevating wheelhouse on the push-boat. For the construction materials of the barges, shipbuilding steel, aluminum and composites, such as carbon were investigated. The construction using composites is technically not feasible. Aluminum has the major advantage of being lightweight and therefore, highly suitable to navigate economically feasible on low water. Nevertheless, from today's perspective, steel has more advantages than aluminium in the construction of barges, such as the robustness of the material and the costs. One major output is, that it depends on the business case, which of the six designs fits best for the purpose of shippping 45’ standard high cube containers between Enns and Giurgiu, as each of the designs have specific advantages and disadvantages. Therefore, the decision of which is the best suitable design should be made depending on the specific business case.

A limitation which leads to further research is that the barge designs are based on the infrastructural requirements of the Danube and cannot similarly be transferred to other waterways without certain adaptations. Furthermore, the new designed barges are specifically designed for container transport. Only a limited number of designs is also feasible for other goods, i.e. bulk goods. Several designs must be adapted for the transportation of other goods than containers. For further research, the research can be extended by optimizing the barges for the Danube stretch Enns-Giurgiu suitable for other goods, e.g., bulk goods or chemical products.