Marine Drive Trim Control for Inward Roll in Multi-Hull Turns
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Solution Overview
Problem
Multi-hull marine vessels experience undesirable outward roll during turns, which is uncomfortable and difficult to handle, and mounting drives at canted angles to mitigate this is undesirable due to maintenance and wear issues.
Innovation Solution
A trim control system that adjusts the trim position of marine drives to mimic the effect of mounting them at canted angles, where outer drives are trimmed down and inner drives are trimmed up during a turn, inducing an inward roll without the need for physical canting, using a controller that adjusts trim based on vessel speed and turn magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drives are mounted at canted angles on multi-hull vessels, then turn behavior is improved with inward roll, but maintenance difficulty and system wear increase
Solution Approach 1:
The patent applies dynamics by making the drive mounts adjustable between vertical and canted angles. The drive units can be dynamically repositioned using hydraulic or electric actuators that allow the operator to change the mount angle from 0 degrees (vertical) to a predetermined canted angle (e.g., 15-30 degrees). This enables the system to adapt to different operating conditions: using canted angles during turns to induce inward roll and improve handling, while returning to vertical orientation during normal operation to minimize maintenance requirements and wear.
Solution Approach 2:
The patent changes the geometric parameter of the drive mount angle dynamically. By adjusting the cant angle parameter between 0 and a predetermined value, the system alters the mechanical configuration to achieve different hydrodynamic effects. During turns, the angle parameter is changed to the canted position to create the inward roll effect, and during normal operation, it is reset to 0 degrees to eliminate the wear and maintenance issues associated with permanent canted mounts.
2Stability of the object's composition
If drives are mounted at canted angles, then inward roll during turns is achieved, but wear on drive systems increases
Solution Approach 1:
The system dynamically adjusts the drive mount angle based on operational needs. During turns, the drives are positioned at canted angles to generate the hydrodynamic forces that induce inward roll and improve vessel stability. During normal straight-ahead operation, the drives are returned to the vertical position (0 degrees), eliminating continuous wear on the canted mount mechanisms and reducing stress on the drive train components.
Solution Approach 2:
The canted angle configuration is applied periodically only when needed for turn correction, rather than being a permanent configuration. The system alternates between the vertical position (normal operation) and canted position (turn operation), thereby limiting the cumulative wear on the adjustment mechanisms and drive system components to only the periods when the canted angle is actively engaged.
3Device complexity
If symmetric trim control is used on multi-hull vessels, then simple control is maintained, but outward roll during turns worsens
Solution Approach 1:
The patent introduces asymmetry into the trim control system by allowing differential trim angles between port and starboard drives during turns. When a turn is detected or commanded, the system applies different trim settings to drives on opposite sides of the vessel - for example, trimming the outer drive down more than the inner drive, or applying asymmetric cant angles. This asymmetric configuration creates a rolling moment that counteracts the natural outward roll tendency of multi-hull vessels during turns, improving stability without requiring complete system redesign.
Solution Approach 2:
The control system applies local quality by allowing individual drive units to have different trim or cant angle settings based on their position and the turn direction. Rather than uniformly controlling all drives symmetrically, the system selectively adjusts specific drives (port vs. starboard, inner vs. outer) to create the desired rolling effect. This localized control approach maintains overall system simplicity while achieving improved roll behavior through targeted asymmetric adjustments.
Data Source
Figure 1A
Figure 1B
Figure 2~3
AI summary
A method of controlling a plurality of marine drives (10a-10d) on a multi-hull marine vessel (14) includes determining, based on steering information, that the multi-hull marine vessel (14) is entering a turn and then receiving a running trim position for each marine drive (10a-10d). A trim position of at least a portion of the plurality of marine drives (10a-10d) is then adjusted from each respective running trim position so as to induce roll of the multi-hull marine vessel (14) during the turn.