Variable Displacement Landing Craft Ballast System
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Solution Overview
Problem
Existing landing craft designs face limitations in payload capacity and operational flexibility due to fixed longitudinal center of gravity (LCG) positions, which restrict their ability to accommodate varying payloads and perform stern-to beaching operations safely.
Innovation Solution
A variable displacement landing craft with a ballast system comprising multiple independently controlled tanks along the hull, allowing for significant shifts in the LCG, enhanced by a transom sponson for additional ballast capacity, enabling up to 80% increase in displacement while tolerating LCG shifts of up to 5% forward and 9% aft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed LCG position is used in existing landing craft, then the vessel structure can be simplified, but the payload capacity and operational flexibility are limited
Solution Approach 1:
The ballast system is divided into multiple independently controllable ballast tanks distributed along the longitudinal axis of the hull. Each tank can be filled or emptied separately, enabling precise control of the LCG position. This segmentation allows the vessel to adapt to different operational requirements (stern-to beaching, payload variations) while maintaining a manageable system architecture through modular tank control.
Solution Approach 2:
The ballast system enables dynamic adjustment of the LCG position during operations. By controlling the ballast tanks independently, the system can shift the LCG forward or aft as needed for different beaching scenarios or payload configurations, transforming a static vessel into a dynamically adaptable platform.
2Stability of the object's composition
If the displacement is increased to improve stability, then the vessel becomes less susceptible to rough weather, but the LCG control range is restricted
Solution Approach 1:
The ballast tanks are strategically positioned at different longitudinal locations along the hull, with multiple tanks distributed from forward to aft sections. This segmented arrangement allows the system to achieve both increased displacement for stability and sufficient LCG control range by selectively filling or emptying specific tanks to shift the center of gravity as needed.
3Reliability
If bow-to beaching is used to avoid grounding risks, then the propulsor is protected from damage, but the operational flexibility for stern-to beaching is lost
Solution Approach 1:
The ballast system enables dynamic trimming of the vessel during beaching operations. By adjusting the LCG position through ballast tank control, the vessel can safely perform stern-to beaching operations where the stern approaches the beach first, allowing the propulsor to remain in deeper water and avoid grounding damage while maintaining operational flexibility.
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
The solution provides enhanced stability and operational flexibility, allowing for greater payload capacity and safe stern-to beaching capabilities, with the ability to adjust draft and balance during landing operations, surpassing existing vessels' performance in LCG control and displacement.
Implementation Method 1
a ballast system located within the hull cavity. The ballast system includes at least three ballast tanks longitudinally distributed along the hull cavity, and each of the three ballast tanks is configured to be independently filled with or emptied of a liquid thereby enabling selective entrapment of the liquid as ballast
Data Source
AI summary
A watercraft according to the present disclosure may include an outer hull that defines an interior or hull cavity, and a ballast system located within the hull cavity. The ballast system may include at least three ballast tanks longitudinally distributed along the hull cavity, and each of the tanks being configured to be independently operated enabling selective entrapment of ballast at three or more different longitudinal locations to enable an intentional shifting of the longitudinal center of gravity (LCG) of the watercraft relative to the design location of the LCG of the watercraft. The watercraft may include at least a forward, a center, and an aft ballast tank, and in some embodiments, additional tanks, in some cases in sponsons, may be included and/or one or more of the forward, center and aft tanks, may be further subdivided for additional active LCG control.