Watercraft Trim Control for Limiting Prolonged Bow-Up Attitude
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Solution Overview
Problem
Existing watercraft designs face challenges with structural loads and system performance when maintained in a bow-up attitude, particularly affecting the lubrication and cooling systems of the engine due to gravity influences.
Innovation Solution
A watercraft system with a propulsion device, trim adjuster, and controller that automatically adjusts the hull trim to maintain an ordinary attitude after a predetermined time in bow-up position, prohibiting further changes until certain conditions are met, and includes alerts for engine abnormalities to prevent excessive bow-up attitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the watercraft maintains a bow-up attitude for extended periods, then the user can achieve improved maneuverability and wave-riding capability, but the structural components experience large loads and the engine's lubrication and cooling systems are adversely affected by gravity
Solution Approach 1:
The controller automatically alternates the trim position between bow-up and ordinary positions based on elapsed time. When the bow-up attitude is maintained for a predetermined period, the controller automatically transitions to an ordinary position, then returns to bow-up after another predetermined period. This periodic switching prevents prolonged exposure to harmful gravitational effects on the engine systems while still allowing the watercraft to utilize bow-up maneuverability when needed.
2Speed
If the trim position is changed rapidly to attain bow-up attitude, then the user can quickly adjust to changing water conditions, but the structural components experience increased dynamic loads
Solution Approach 1:
The controller dynamically adjusts the trim position based on real-time conditions including elapsed time in bow-up attitude, engine operating parameters, and watercraft motion state. This dynamic control allows rapid transition when needed while automatically modulating the trim changes to prevent excessive structural loads, adapting the response speed to current operational conditions.
3Reliability
If the watercraft operates in bow-up attitude, then the user can maintain position against strong currents or waves, but the engine experiences adverse gravity influences on lubrication and cooling systems
Solution Approach 1:
The controller implements periodic switching between bow-up and ordinary positions. When the watercraft has been in bow-up attitude for a predetermined time, the controller automatically transitions to an ordinary position to allow proper lubrication and cooling system operation, then returns to bow-up after another predetermined period. This periodic action maintains position-holding capability when needed while preventing prolonged gravitational adverse effects on engine systems.
Data Source
AI summary
A watercraft includes a propulsion device, an accelerator operator, a trim adjuster, a trim operator, and a controller configured or programmed to control a trim position. The trim positions include a bow-up position to attain a bow-up attitude in which a bow is raised and at least one ordinary position to attain an ordinary attitude in which the bow is closer to a water surface than in the bow-up attitude. The controller is configured or programmed to determine whether or not a hull is in the bow-up attitude and, when a duration of the bow-up attitude reaches a predetermined time limit, executes a forced trim down control by which the trim position is controlled to the ordinary position. The controller may be configured or programmed to prohibit a change to the bow-up position for a predetermined resume prohibit time after executing the forced trim down control.