Safe Under Keel Clearance Calculation for Ultra-Large Ships
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining safe under keel clearance for ultra-large ships rely on experience values and do not consider dynamic draught changes during navigation, particularly in shallow water, leading to increased navigation dangers and reduced loading rates.
Innovation Solution
A method and system that acquire operation parameters, calculate fluid pressure, determine squat force and trim moment, establish a mirror image model based on velocity potential, and compute safe under keel clearance by accounting for draught changes, heeling effects, and oil-water consumption to control squat clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If experience values are used to determine safe under keel clearance, then the method is simple to implement, but it does not consider dynamic draught changes and leads to increased navigation dangers
Solution Approach 1:
The patent transforms the static experience-based clearance determination into a dynamic calculation by introducing multiple changing parameters including ship speed, water depth, draught changes, squat effects, and trim moments. The calculation model continuously updates the safe under keel clearance based on real-time operational parameters, resolving the contradiction between simplicity and reliability by providing accurate dynamic assessment without requiring complex physical models.
Solution Approach 2:
The patent replaces the empirical/mechanical judgment method with a mathematical calculation system based on fluid dynamics principles. By using velocity potential theory and mirror image models to calculate hydrodynamic forces and moments, the system substitutes subjective experience with objective computational mechanics, achieving both reliability and manageable complexity through standardized mathematical formulations.
2Productivity
If traditional methods are used to determine under keel clearance, then the calculation process is simple, but the loading rate of the ship is reduced due to excessive safety margins
Solution Approach 1:
The patent introduces dynamic analysis of draught changes during navigation, considering squat effects, trim changes, and wave interactions that occur when ships move through shallow water. By calculating the actual dynamic clearance requirements rather than using static fixed margins, the system enables higher loading rates while maintaining safety by accurately reflecting the true clearance needs under various operational conditions.
Solution Approach 2:
The patent performs preliminary calculation of squat forces and trim moments before finalizing the safe under keel clearance determination. By pre-computing the hydrodynamic effects based on ship characteristics and operational parameters, the system establishes accurate safety margins that prevent excessive conservative estimates, thereby improving loading rates while ensuring navigation safety.
3Reliability
If dynamic draught changes are considered in shallow water navigation, then navigation safety is improved, but the calculation complexity increases significantly
Solution Approach 1:
The patent employs mirror image modeling to simplify the complex hydrodynamic calculations. By creating virtual mirror images of the ship and free surface in the mathematical model, the system captures complex wave-ship interactions and boundary effects without requiring computationally intensive simulations. This copying approach resolves the contradiction by providing accurate dynamic safety assessment through simplified mathematical representations of complex physical phenomena.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively avoids navigation hazards and improves loading rates by accurately determining safe under keel clearance, enhancing the safety and operational efficiency of ultra-large ships in shallow water conditions.
Implementation Method 1
obtaining fluid pressure according to the operating parameter values of the ultra-large ship; obtaining a squat force and a trim moment of the ultra-large ship according to the fluid pressure
Implementation Method 2
establishing a mirror image model based on a velocity potential; establishing a squat clearance calculation model for an ultra-large ship according to the established mirror image model based on the velocity potential
Data Source
AI summary
A method and a system for determining a safe under keel clearance of an ultra-large ship are provided. The method comprises: acquiring operation parameter values of the ship; obtaining fluid pressure according to the values; obtaining a squat force and a trim moment of the ship according to the pressure; establishing a mirror image model based on speed potential to establish a squat clearance calculation model for the ship; determining a half-wave rising height with above calculation model; obtaining draught and trim changes according to the squat force and the trim moment, to determine a maximum squat clearance of the hull; determining the safe under keel clearance; and controlling the squat clearance of the ship according to the safe under keel clearance of the ship, to avoid navigation dangers, and improve the loading rate.