Pivoting Spreader Bar for Rigid Sail Storage and Support

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Solution Overview

Problem

Existing sail propulsion systems with rigid sails face challenges in storage due to their rigidity, which prevents them from being lowered like conventional sails, and the presence of spreaders complicates storage by increasing the overall size when furled.

Innovation Solution

A sail propulsion system with a rigid sail that includes a spreader pivotally mounted to extend against the sail wall in a stowed position, shrouds that remain taut whether in sailing or stowed positions, and a base with a rotating element to adjust the sail's angle of incidence, allowing for efficient storage and navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid sail is used to improve aerodynamic efficiency, then aerodynamic performance is improved, but storage becomes difficult because the rigidity prevents the sail from being lowered like conventional sails

Engineering Contradiction:
Improveaerodynamic efficiencyVSAvoidstorage capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spreader is made dynamically adjustable, allowing it to pivot between a sailing position (extending perpendicular to the sail wall) and a stowed position (extending against the sail wall). This dynamic reconfiguration enables the rigid sail system to adapt its structure for both optimal aerodynamic performance during sailing and compact storage when not in use, resolving the contradiction between rigidity-based efficiency and storage flexibility

Inventive Principle:
Principle #15Dynamics

2Strength

If spreaders are mounted on the mast to stiffen it, then mechanical resistance is improved, but storage is complicated because the spreader increases the overall size of the sail when furled

Engineering Contradiction:
Improvemechanical resistanceVSAvoidstorage volume
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The spreader is designed with pivotal mounting that allows it to change its spatial configuration dynamically. During sailing, it extends perpendicular to provide structural stiffening and mechanical resistance. During storage, it pivots to extend against the sail wall, minimizing the overall volume occupied by the sail assembly. This dynamic repositioning resolves the contradiction between needing structural strength and minimizing storage volume

Inventive Principle:
Principle #15Dynamics

3Strength

If the spreader extends perpendicular to the sail wall in sailing position, then mechanical support is optimized, but the overall size increases when the sail is furled

Engineering Contradiction:
Improvemechanical supportVSAvoidoverall size
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The spreader's pivotal mounting allows it to adopt different orientations based on operational requirements. In sailing position, it extends perpendicular to the sail wall to maximize mechanical support and structural stability. In stowed position, it pivots to extend against the sail wall, minimizing the protruding length and overall size of the furled sail assembly, thus resolving the contradiction between mechanical support optimization and size minimization

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4479300B1Pivoting spreader bar for a rigid sail
Publication Date: 2026.01.28 SHIP ST
  • EP4479300B1 patent drawingFigure 1~2a
  • EP4479300B1 patent drawingFigure 2b~3
  • EP4479300B1 patent drawingFigure 4a~4b

AI summary

The invention relates to a sailing propulsion assembly for a boat (100), comprising: • - a rigid sail (10), • - a spreader bar (81, 82) pivotably mounted relative to a wall (11, 12) of the rigid sail (10), between a sailing position in which the spreader bar (81, 82) extends substantially perpendicularly to the wall (11, 12), and a stowed position in which the spreader bar (81, 82) extends substantially against the wall (11, 12), and • - at least two shrouds (91, 92) mounted on the spreader bar (81, 82), wherein, when the spreader bar (81, 82) is in the stowed position, the shrouds (91, 92) extend substantially against the wall (11, 12) of the rigid sail (10).