Powerboat Hull Trim Control via Adjustable Hydrofoils
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Solution Overview
Problem
Powerboats designed for high speeds have high hydrodynamic resistance at low speeds, making them inefficient and fuel-intensive when operating at cruising speeds, and vice versa, due to the need for different hull shapes for displacement and planing modes.
Innovation Solution
A powerboat with dynamically adjustable hydrofoils positioned below the waterline, which control the running trim and reduce drag at low speeds while enabling efficient high-speed operation by supporting a portion of the boat's weight and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a hull shape is designed for high-speed planing operation, then the boat can achieve high speeds, but the hydrodynamic resistance increases significantly at low cruising speeds
Solution Approach 1:
The patent applies dynamics by making the hull shape adjustable through waterjet deflectors that can change the effective cross-sectional area of the hull. At high speeds, the deflectors are positioned to create a planing hull shape for efficient high-speed operation. At low speeds, the deflectors are repositioned to increase the effective hull area, reducing hydrodynamic resistance and improving fuel efficiency during cruising operations.
2Loss of energy
If a hull shape is designed for low-speed displacement operation, then fuel efficiency improves at cruising speeds, but the boat cannot achieve high speeds efficiently
Solution Approach 1:
The patent uses dynamic adjustment of the hull shape through waterjet deflectors. During low-speed displacement operation, the deflectors are positioned to maximize hull surface area for efficient fuel consumption. When high speed is required, the deflectors are repositioned to minimize the effective hull area and create a planing configuration, enabling the boat to achieve high speeds efficiently.
3Loss of energy
If the hull cross-sectional area is reduced towards the rear to minimize wetted area, then hydrodynamic resistance decreases, but the boat loses stability and control at high speeds
Solution Approach 1:
The patent applies dynamics by using adjustable waterjet deflectors that can change the effective hull shape. At low speeds, the deflectors create a streamlined shape with reduced wetted area for minimum resistance. At high speeds, the deflectors are repositioned to increase the effective rear hull area, providing the stability and control needed for safe high-speed operation while maintaining low resistance during cruising.
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 powerboat achieves low drag at low speeds and efficient, safe operation at high speeds, optimizing fuel efficiency and reducing emissions across a wide range of speeds without the need for multiple hull designs.
Implementation Method 1
the boat's weight is supported partly by hydrostatic buoyancy and partly by hydrodynamic lift
Implementation Method 2
the weight of the boat is supported by hydrostatic buoyancy forces
Implementation Method 3
the wetted area of the hull is minimized, and the zone of separated flow at the transom is reduced, both of which in turn reduce the hydrodynamic resistance
Data Source
AI summary
A powerboat comprising a hull, a plurality of dynamically adjustable hydrofoils positioned below the waterline towards the rear of the hull, and a control system, wherein the cross sectional area of the hull below the waterline decreases towards the rear of the hull, and the control system is configured to adjust the hydrofoils in operation of the powerboat to control the running trim of the powerboat. The powerboat can operate efficiently at over a wide range of Froude numbers, in particular both low (displacement mode) speeds and high (planing mode) speeds.