MAXSURF Study
MAXSURF is a leading 3D surface computer modelling system used for ship design and hydrostatic analysis. MAXSURFs resistance module has been chosen in order to estimate the resistance and power requirements for a bulk carrier fitted with a single flettner rotor using industrially approved prediction methods.
Firstly, a conventional bulk carrier hull form was taken from MAXSURFs library of hull forms and modified to fit specific requirements. This design was taken as it is a good representation of the ship type required and has relative ship parameters as seen in the following table and figures.
This hull form was imported into MAXSURF resistance and the Holtrop calculation method was chosen to predict the calculations. The Holtrop method is a statistical regression method used to estimate the resistance of displacement ships with high block coefficients and low length: breadth ratios. The resistance and power analysis was carried out over a range of 1-40 knots in order to represent a large range of ship speeds that may be encountered by a bulk carrier at sea. In this calculation the efficiency is assumed to be 100%. A final ship speed of 13.3 knots was chosen for the given route.
As an engine is chosen for the ship the efficiency of this system can be inputted to give correct power requirements for each speed.
In literature (Holtrop & Mennen, 1982) [1], the total resistance of a ship is described using the following equation.
Where:
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R_F= Frictional Resistance according to ITTC 1957.
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(1+k_1)= Form factor describing the viscous resistance of the hull form about RF.
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R_APP= Resistance of appendages.
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R_W= Wave-making and wave-breaking resistance.
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R_B= Additional pressure resistance of bulbous bow near the water surface.
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R_TR= Additional pressure resistance of immersed transom stern.
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R_A= Allowance resistance.
The power calculation produced by MAXSURF Resistance module is as follows.
Where:
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R=Ship Resistance
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V=Ship Velocity
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η=Engine Efficiency
The efficiency being used is the same at all speeds and the value entered depends on the desired power outcome. E.g. effective power (unity) or shaft power. These equations were satisfied using MAXSURF giving a ship resistance and power requirement of 1304487.65 kN and 8924 kW, respectively.
