Ramform Hull Bulge Configuration for Vessel Stability
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Solution Overview
Problem
Traditional Ramform™ ship hull designs face limitations in sea-keeping qualities and propulsion characteristics due to a narrow beam-to-draught ratio, leading to high rolling movements and resistance at varying speeds.
Innovation Solution
The beam-to-draught ratio is significantly increased, with bulges extending along the hull and terminating in a projecting bulb member above the waterline, and skeg placement optimized for improved stability and propulsion, while maintaining hull length and draught.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the beam-to-draught ratio is increased significantly (to between 10 and 12), then sea-keeping qualities and propulsion characteristics are improved, but the hull form deviates substantially from traditional Ramform™ configurations
Solution Approach 1:
The patent applies parameter changes by significantly increasing the beam-to-draught ratio from traditional values (less than 1.4) to new values between 10 and 12. This fundamental parameter change transforms the hull geometry to achieve improved sea-keeping qualities and propulsion characteristics while maintaining the essential Ramform™ displacement hull type with sinusoidal waterlines.
2Stability of the object's composition
If the beam of the hull is increased whilst maintaining length and draught, then rolling movements and acceleration are reduced, but the hull cross-sectional area and displacement increase
Solution Approach 1:
The patent applies dimensionality change by extending bulges both horizontally and vertically from the hull, with the bulges terminating in a tongue-like bulb member that projects forward. This three-dimensional configuration increases the beam effectively while distributing the volume increase across multiple spatial dimensions, reducing rolling movements through increased moment of inertia without excessive displacement increase.
3Productivity
If bulges extend both horizontally and vertically out from the hull beyond maximum beam, then propulsion characteristics are improved, but the hull form complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the hull into distinct functional zones: the main hull body, lateral bulges extending from the hull, and the forward-projecting tongue-like bulb member. This segmentation allows each component to be optimized for its specific function (stability, propulsion, maneuverability) while simplifying the manufacturing process through modular construction approaches.
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 configuration reduces rolling movements and acceleration, maintains low resistance across speeds, and enhances maneuverability by increasing the added mass effect and viscous damping, resulting in improved sea-keeping qualities and propulsion efficiency.
Implementation Method 1
The sea-keeping qualities of the hull configurations according to the present invention will thus be improved through geometrical changes of the beam of the hull with respect to its draught and in connection with these relationships a lengthening and twisting of the bulges in the hull, including the termination of the bulges in the forward part of the ship, in the form of a projecting bulb member that ends above the design waterline plane. The aftermost parts of the bulges terminate below the sloping plane towards the outer edges of the transom stern, causing the rolling movements of the hull, and the associated levels of acceleration to be reduced and the propulsion characteristics improved
Implementation Method 2
The advantages achieved include maintaining the comparatively low resistance in the sea at varying speed.
Data Source
AI summary
The invention relates to a ship of the displacement type with a Ramform™ hull that has a transom stern (100), a longitudinal length L in the design waterline plane (300), a base plane (400) parallel with the design waterline plane at a distance T corresponding to the design draught of the hull and including essentially sinusoidal waterlines (602), a sloping plane (200) that comprises the bottom of the after end of the ship and which extends from the transom stern (100) at the design waterline plane (300) to the base plane (400) at approximately L/2 and a bulge on each side along a considerable part of the length of the hull, terminating at the forward end of the hull ahead of the length L in a tongue-like bulb member (900). The relationship between the maximum beam B and the design draught T is considerably more than 7, preferably between 10 and 12, and where the bulges (901) form the bulb member (900) and aft towards L/2 have a transversal horizontal orientation from the surface of the hull and which from about L/2 rotate gradually downward 90 degrees into a vertical orientation so that the bulge (902) at the transom stern (100) lies below the sloping plane (200) and along the outer edges of the sloping plane, but within the maximum beam B and above the base plane (400).