Segmented Hydrodynamic Mast Columns for Radar Discretion

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Solution Overview

Problem

Current underwater vehicle masts with cylindrical structures cause significant radar equivalent signature, water spray, and wake signatures, compromising mission discretion due to their design.

Innovation Solution

The use of hydrodynamically tapered mast columns spaced apart and connected by a transverse bar, with radar-transparent materials and cone-shaped aerial means to minimize hydrodynamic interference and radar signatures, along with rotating parts for 360° visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If cylindrical masts with large section are used, then structural strength is improved, but radar signature and wake signature increase

Engineering Contradiction:
Improvestructural strengthVSAvoidradar signature and wake signature
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The mast is divided into multiple thin columns (typically three) spaced apart from each other, rather than using a single solid cylindrical structure. This segmentation reduces the radar cross-section and minimizes wake signature while maintaining structural integrity through the spaced arrangement and inter-column bracing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional solid cylinder to a three-dimensional spaced columnar structure. By distributing the mast function across multiple columns in space rather than concentrating it in a single solid form, the design achieves reduced hydrodynamic and radar signatures while preserving structural strength.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If mast crosses the diopter when hoisted, then periscopic immersion capability is improved, but water spray and wake are generated

Engineering Contradiction:
Improveperiscopic immersion capabilityVSAvoidwater spray and wake
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The mast structure is segmented into multiple thin columns that can be hoisted independently or together. This segmentation allows the mast to cross the diopter (water surface) with minimal displacement, reducing water spray and wake generation while maintaining the ability to achieve periscopic immersion depth.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mast columns are positioned and dimensioned to have different local characteristics - thin sections where they cross the diopter to minimize spray, and adequate spacing to allow water flow through the structure. This local optimization reduces harmful hydrodynamic effects while maintaining overall functionality.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If aerial means are mounted on mast, then sensor capability is improved, but indiscretion increases

Engineering Contradiction:
Improvesensor capabilityVSAvoidindiscretion
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The aerial means (sensors, antennas, etc.) are distributed among multiple spaced columns rather than concentrated on a single solid mast. This segmentation reduces the radar cross-section and visual signature while maintaining sensor capability, as the sensors can be positioned on different columns or on a platform connecting them.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mast structure uses thin-walled columns that minimize radar reflection and visual detection. These thin structures support aerial means while presenting a minimal profile to radar and optical detection systems, thereby maintaining sensor capability without increasing indiscretion.

Inventive Principle:
Principle #30Flexible shells and thin films

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

This design enhances mast discretion by reducing water spray and wake, while maintaining radar transparency and improving hydrodynamic performance, especially during periscopic immersion.

Implementation Method 1

hydrodynamically profiled mast columns which can be hoisted independently of one another

Methodology Applied
Scientific EffectHydrodynamic flow: Flow Separation

Implementation Method 2

made of a material transparent to radar waves to improve the discretion of the mast

Methodology Applied
Scientific EffectRadar wave transparency: Absorption (EM radiation)

Data Source

PatentEP4161832B1Underwater vessel of the type comprising at least one hoistable mast
Publication Date: 2024.11.13 NAVAL GRP
  • EP4161832B1 patent drawingFigure 1
  • EP4161832B1 patent drawingFigure 2
  • EP4161832B1 patent drawingFigure 3

AI summary

This underwater vessel of the type comprising at least one hoistable mast (10), in the vicinity of the upper end of which there are arranged means forming antennas (11) equipped with sensors connected to the rest of the underwater vessel, is characterized in that the hoistable mast (10) comprises, at least at its portion intended to pass through the dioptre when the mast is hoisted, at least two profiled mast columns in the form of a slender hydrodynamic profile (12, 13) that are spaced apart from one another.