Ship Resistance and Power Simulator

This repository provides clean, vectorized MATLAB and Python implementations of the Holtrop–Mennen empirical method for estimating ship resistance and propulsion power.
The reference case corresponds to a Royal Caribbean Oasis-class cruise ship, but the scripts can be adapted to other displacement vessels by modifying the input parameters.

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📌 Features

• ITTC-1957 frictional resistance formulation
• Full Holtrop–Mennen wave resistance model
• Bulbous bow, appendage, and correlation resistance terms
• Effective power and shaft power estimation
• Both MATLAB and Python implementations with identical results

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⚙️ Requirements

MATLAB

• MATLAB R2020a or newer
• No additional toolboxes required

Python

• Python 3.7 or newer
• NumPy
• Matplotlib

Install Python dependencies:

pip install numpy matplotlib

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▶️ Usage

MATLAB

1. Clone or download the repository
2. Open MATLAB in the project directory
3. Run:

PropulsionResistancePower

Python

1. Clone or download the repository
2. Navigate to the project directory
3. Run:

python PropulsionResistancePower.py

Both scripts will:

• Compute resistance and power over a speed range (0-30 knots)
• Generate resistance and power curves
• Save figures to the figures/ folder

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🛠️ Modifying the Ship Geometry

Edit the Ship Data section in either PropulsionResistancePower.m or PropulsionResistancePower.py:

MATLAB:

Lbp = 330;    % Length between perpendiculars [m]
B   = 47;     % Beam [m]
T   = 9.1;    % Draught [m]
vol = 110000; % Displacement volume [m^3]

Python:

Lbp = 330     # Length between perpendiculars [m]
B = 47        # Beam [m]
T = 9.1       # Draught [m]
vol = 110000  # Displacement volume [m^3]

All coefficients are derived automatically from these parameters.

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📊 Output

Both implementations generate two plots:

1. Resistance.png: Total ship resistance vs. speed
2. Power.png: Effective power and shaft power vs. speed

Plots are saved in the figures/ directory with consistent formatting between MATLAB and Python versions.

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📖 References

• Holtrop, J., & Mennen, G. G. J. (1978). A Statistical Power Prediction Method.
• Holtrop, J., & Mennen, G. G. J. (1982). An Approximate Power Prediction Method.
• Kristensen, H. O., & Lützen, M. (2012). Prediction of Resistance and Propulsion Power of Ships.

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👤 Author

Albert Gil Esmendia