Here are some of the conclusions:


Bow shapes Extremely curved waterlines around the fore shoulders cause large traverse wave systems, resulting in increased resistance. Smoothing the fore shoulders can overcome this problem and save fuel consumption.


Tunnel design


Since inland vessels are sailing at low Froude number numbers, the wave making resistance is a small part of the total resistance. However, more can be gained by reducing the viscous resistance. Inland vessels have typical aftbod- ies with propeller tunnels designed to sail in shallow water. With its partners, MARIN is investigating how the tunnel design can be improved to reduce resistance.


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Ship model used to test different rudder configurations


from the model tests. Comparisons showed that the prediction corresponded very well with the full-scale results and this confirms the validity of MARIN’s extrapolation method for shallow water model tests.


Full-scale speed trials were also performed in deep water. A speed-power prediction was made based on the correction method of Lackenby (1965). Trial results showed that the correction of Lackenby was too large but MARIN’s new shallow water correction method proved to be much closer to the trial results.


Is retrofitting viable? Several projects are developing viable options to improve the performance of existing inland vessels such as the EU project MoVe IT! and Joint Industry Project SAVE. In both projects hydrodynamic improvements are being investigated for self-propelled barges as push barge convoys are part of the research


activities. Based on full-scale measurements the performance of the vessels has been defined. The goal of these measurements was to be able to compare the performance of different inland waterway vessels.


Some of the issues addressed in these projects included the optimisation of rudder designs and configurations, tunnel designs and reduction resistance by the optimisation of bow designs. By means of measurements, advanced calculations such as CFD methods, and in some cases model tests, MARIN found interesting changes in individual situations that could significantly reduce fuel consumption. It is clear that the Return on Investment for all modifications would have been far more interesting if they had been considered in the design stage. However, even as a retrofit option, they pro- vide interesting options for the optimisation of existing vessels as well.


Optimised vessel Semper Fi has 20% lower fuel consumption In 2005 Wilco Ooms, Director of Carpe Diem Inland Shipping, had the idea to develop an inno- vative and energy efficient inland vessel and he asked MARIN’s advice about how to achieve the lowest possible resistance. MARIN started analysing the hull lines of his ‘old’ vessel, Carpe Diem. The first modification was to remove the gondolas and tunnels in the aft ship to be able to accommodate two thrusters. The aft ship was further optimised by viscous flow calculations and the bow by means of potential flow calculations to im- prove the wave making resistance. The effect of shallow water was taken into account in all the calculations. The new vessel, Semper Fi, is now in operation and has 20% lower fuel consumption than his other vessel!


* Raven, H.C.; “A computational study of shallow water effects on ship viscous resistance”, 29th Symposium on Naval Hydrodynamics, Gothenburg, August 2012.


report 11 udder design


A typical rudder applied on an inland vessel is a fish is a fishtail rudder. Recent measurements in MARIN’s Shallow Water Basin showed that replacing these fishtail rudders with more stream- lined bodies can reduce the power consump- tion by up to 16%. As not only resistance, but also manoeuvrability is very important, all conclusions will be carefully checked before considering this as a viable retrofit option.


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