Boat Ducted Propeller with Curved Converging Nozzle

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Solution Overview

Problem

Existing boat propulsion systems, such as those with multiple engines and complex conduit designs, compromise maneuverability and efficiency, particularly in port maneuvers and forward gear operations.

Innovation Solution

A boat design featuring a thermal engine and symmetrically arranged electric motors with propellers in conduits that include converging sections for optimized water flow, a continuous curved front section to reduce pressure losses, and strategically positioned side and rear orifices to enhance maneuverability and efficiency in both forward and reverse movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the conduit includes converging sections to optimize water flow, then propulsion efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvepropulsion efficiencyVSAvoidconduit structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The conduit incorporates curved sections with specific radii (R1, R2, R3) to guide water flow smoothly from the lateral orifice to the rear orifice. The curved profile reduces flow separation and pressure losses while maintaining a relatively simple monolithic structure that can be manufactured as a single piece.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of operation

If the front section is oriented at an angle of 20-60° relative to the wall, then maneuverability is improved, but device complexity increases

Engineering Contradiction:
ImprovemaneuverabilityVSAvoidconduit orientation complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The conduit is designed with asymmetric orientation where the front section forms an angle of 20-60° relative to the transom plane. This asymmetric configuration optimizes the water jet direction for enhanced maneuverability during port operations while the entire conduit remains a single integrated component.

Inventive Principle:
Principle #4Asymmetry

3Loss of energy

If the continuous curved profile is used in the front section, then pressure losses are reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvepressure lossesVSAvoidcurved profile precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The front section employs a continuous curved profile with defined radii (R1, R2, R3) that smoothly transitions water flow from the lateral orifice through the conduit to the rear orifice. This curved geometry minimizes flow separation and pressure losses while the parameters are optimized for manufacturability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Device complexity

If a single thermal engine and two electric motors are used, then device complexity is reduced, but maneuverability is compromised

Engineering Contradiction:
Improvenumber of enginesVSAvoidmaneuverability
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The system dynamically controls the two electric motors independently, allowing differential power delivery to each propeller. This dynamic control enables precise maneuvering in port while maintaining a simpler three-engine configuration compared to traditional four-engine setups, with the thermal engine providing auxiliary power when needed.

Inventive Principle:
Principle #15Dynamics

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 design improves maneuverability and propulsion efficiency by optimizing water flow directionality and reducing pressure losses, allowing for effective turning and efficient movement in all directions.

Implementation Method 1

the conduit comprises at least one convergent in the direction of a flow going from the side orifice towards the rear orifice

Methodology Applied
Scientific EffectConvergent flow: Pressure Gradient

Implementation Method 2

the front section has a continuous curved profile, and the front section is oriented so that the flow of water leaving the side orifice is directed in a forward-facing direction

Methodology Applied
Scientific EffectFlow separation reduction: Turbulence

Data Source

PatentEP3717348B1Boat comprising engines that have propellers each positioned in a duct, ensuring optimised operation during forward travel and high manoeuvrability
Publication Date: 2025.01.08 PINBALL BOAT
  • EP3717348B1 patent drawingFigure 1~2
  • EP3717348B1 patent drawingFigure 3~5
  • EP3717348B1 patent drawingFigure 6~8

AI summary

The invention relates to a boat which comprises at least one combustion engine (32) positioned on or symmetrical with respect to the vertical median plane of the boat and two engines provided symmetrical with respect to the vertical median plane, which each comprise a propeller (42) provided in a duct (44) which has: a central section (46) on which the propeller (42) is positioned, a rear section (48) that leads via at least one rear opening (50) onto the transom (16.1, 16.2) of the hull (12.1, 12.2), a front section (52) that has a continuous curved profile, which leads via at least one side opening (54) to the outside wall of the hull (18.1, 18.2), the side opening (54) having a larger cross-section than the cross-section of the rear opening (50) in order for the duct (44) to comprise at least one converging nozzle, the front section (52) being oriented so that the stream of water exiting from the side opening (54) is directed towards the front and forms an angle of 20º to 60º with respect to the wall of the hull (18.1, 18.2).