Hull-Mounted Steerable Marine Drive With Trim Actuation
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Solution Overview
Problem
Current marine propulsion systems, such as inboard outboard drives and pod drives, face limitations in hydrodynamic efficiency and wake performance, especially in high-performance boats, due to exposure of hydraulic systems to water and lack of adjustable trim, which affects steering and trimming capabilities.
Innovation Solution
A hull-mounted, steerable marine drive system with trim actuation that includes an enclosure assembly for sealing the hull, a forward-neutral-reverse transmission, drive unit assembly with trim foils, and a breakaway detachment system to protect components from water exposure, allowing for 360-degree steering and adjustable trim from +3 to -15 degrees, enhancing hydrodynamic efficiency and wake performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the hull cavity is exposed to elements and filled with water as in Wilson's design, then serviceability is improved, but hydrodynamic efficiency and wake performance deteriorate
Solution Approach 1:
The patent employs a flexible waterproof gasket or membrane that seals the hull cavity opening. This flexible barrier prevents water ingress while maintaining the ability to access the drive unit for serviceability, resolving the contradiction between an open accessible design and a sealed hydrodynamic design.
2Ease of operation
If the hydraulic motor is exposed to water in Wilson's open cavity design, then ease of access is improved, but reliability deteriorates
Solution Approach 1:
A flexible waterproof gasket or membrane seals around the hydraulic motor, allowing it to remain accessible within the hull cavity while preventing water contact. This maintains ease of access for operation and maintenance while ensuring hydraulic system reliability through water exclusion.
3Adaptability or versatility
If trim tabs are used to adjust trim angle in pod drives, then trim adjustability is improved, but drag increases
Solution Approach 1:
The patent implements a dynamic trim system where the entire pod assembly can be trimmed by pivoting at a transom hinge, rather than using static trim tabs. This dynamic adjustment mechanism provides trim control without the continuous drag penalty of fixed trim tabs, as the trim surface is only present when needed for attitude adjustment.
4Productivity
If the propeller extends beyond the rear of the boat in I/O drives, then propulsion efficiency is improved, but safety deteriorates due to prop strike risk
Solution Approach 1:
The patent nests the propeller and lower unit within the hull structure itself, integrating the drive unit into the boat's architecture. The propeller remains positioned for efficient propulsion while being recessed within the hull boundaries, eliminating the protruding hazard that creates prop strike risk to swimmers and bystanders.
Data Source
AI summary
A hull mounted, steerable marine drive system having trim actuation is both steerable through 360 degrees and is trimmable. The marine drive system includes a watertight enclosure assembly for sealing the hull, which is adapted for keeping much of the marine drive system from being exposed to water. The enclosure includes a gasket flange plate, a retention plate and a folded gasket. The gasket flange plate closely follows the contour of the hull and enhances the hydrodynamic and wake performance of the present marine drive system. Further, marine drive system includes a forward-neutral-reverse (FNR) transmission assembly, a drive unit assembly having a trimmable upper unit and a steerable lower unit, a steering actuator assembly, a trim actuator assembly, and, preferably, trim foils for providing enhanced negative and positive trim and for providing enhanced positive and negative lift.