Maritime UX · Human Factors
SEEING

A self-stabilising projector that gives enclosed ship crew a constant visual horizon — ending the sensory mismatch behind motion sickness.

01 — The Problem

The Windowless Crisis at Sea

Crew work 10–12 hour shifts in enclosed interiors with no visual horizon. The brain receives conflicting signals — with debilitating results.

01

Health Impact

Nausea, dizziness, vomiting, long-term fatigue — repeated across every rough-sea period.

Severity88%
02

Operational Impact

Reduced productivity and critical task errors — directly affecting ship operations and service quality.

Severity74%
03

Safety Risk

Impaired focus and disorientation — posing real risks to crew and passengers in rough conditions.

Severity81%
04

No Exit Strategy

Crew cannot leave posts to recover. Symptoms compound over the entire 10–12 hour shift.

Severity92%

How HorizonLine Works

The ship tilts — the projected horizon stays perfectly level. Your brain finally has a stable reference it can trust.

Root Cause — Sensory Mismatch
Inner Ear

Detects constant tilting, rolling & vibration

Eyes

See a static, windowless room — no horizon

Brain Conflict

Nausea, disorientation & cumulative fatigue

Sensory Conflict Theory — Oman, 1990
02 — Target Users

Who Bears the Burden

Three crew roles face the greatest exposure. Hover to reveal pain points.

Highest Risk

Galley Staff

Long hours in windowless kitchens under pressure — no ability to pause.

Hover to reveal →

Pain Points

  • 10–12 hr shifts without a window
  • Cannot leave post during rough seas
  • Knife work while nauseous
  • Heat + motion = compounded symptoms
Mobility Risk

Housekeeping

Constant movement through enclosed cabins — balance challenges all shift.

Hover to reveal →

Pain Points

  • Moving floors while carrying loads
  • Enclosed corridors, no reference
  • Fall risk during balance disruption
  • Must maintain full speed all shift
Precision Risk

Service Staff

Navigate tight, uneven surfaces while maintaining professional demeanor.

Hover to reveal →

Pain Points

  • Carrying trays on unstable surfaces
  • Must hide discomfort from guests
  • Zero margin for error
  • Small dining rooms amplify symptoms
Francis Mendez — Galley Cook
Primary User Persona
Francis Mendez
Galley Cook · 8 Years at Sea
38Age 11hAvg Shift 3–4×Sick per voyage 0Windows at post
"

When the ship starts rolling, everything inside the galley moves — but my eyes have nothing fixed to hold on to. I feel it in my stomach first, then my hands start to shake. I've learned to just push through it, but it never gets easier. You can't leave. You can't stop. You just endure.

— Francis, during rough sea state 4

Francis has been cooking at sea since his early thirties — long enough that the work itself is second nature. It's the environment that wears him down. The galley sits two decks below the waterline, a sealed box of stainless steel with no portholes, no horizon, no way to tell up from down except through the floor beneath his feet. On calm days it's manageable. When the weather turns, his body starts fighting him before his mind even registers the change.

He knows the medication exists. He rarely takes it — it makes him drowsy, and a drowsy cook in a moving kitchen is a dangerous one. So instead he grips the counter, widens his stance, and works through the nausea. He's never been asked what would help. No one has.

Goals
  • Complete every shift safely, without incident
  • Maintain the standard he's proud of — fast, clean, precise
  • Not have to hide how he feels from his colleagues
  • Get through rough sea days without losing hours to recovery
Frustrations
  • There is no escape — he cannot leave the galley mid-service
  • Medication causes drowsiness, which is worse than the nausea
  • Errors mount as disorientation compounds through the shift
  • The problem is treated as personal weakness, not environment
What He Needs
  • A stable visual reference that works passively — no action required
  • Something built into the environment, not worn or carried
  • A solution that doesn't alter how he works or what he wears
  • Relief that's always on, not something he has to remember
Emotional Arc — A Rough Sea Day
06:00
Calm, focused
07:30
Seas roughen
09:00
Nausea sets in
11:00
Peak distress
14:00
Errors, fatigue
18:00
Shift ends
03 — Design Question

How Might We…

The design challenge that shaped every decision.

Core Design Question

Visual Reference Enclosed Interiors Non-Intrusive Crew Wellbeing Rough Sea Conditions No Workflow Disruption
04 — Concept Ideation

From Idea to Form

Early sketches exploring how a self-stabilising projector could solve the sensory conflict problem — before a single component was sourced.

HorizonLine concept sketch sheet showing ideation exploration, exploded view of components, form explorations, mounting options, detail sketches, and context renders in a ship corridor
Industrial Design Ideation Sheet
Concept Sketches

Core Idea

A gimbal-mounted projector housing that uses a counterweight to stay level as the ship rolls — no active electronics needed for the stabilisation itself.

Exploded View

Component Architecture

Seven layers: Top Cover → Stabilising Weight → Gyroscope Module → Drive & Control → LED Ring Emitter → Outer Housing → Wall Mount Bracket.

Form Explorations

Shape Language

Compact cylindrical body with the red accent ring marking the active emitter zone — industrial aesthetic that reads as safety equipment, not consumer tech.

Mounting Options

Three Install Modes

Wall mount for corridors, corner mount for enclosed cabins, ceiling mount for open mess decks — one device, three installation configurations.

Detail Sketches

Dimensions

Compact footprint at ~180 × 120mm, sized to fit existing ship wall conduit brackets with no structural modification to the vessel.

Context Sketches

In-Situ Vision

The red horizon line projected across a ship corridor wall — at eye height, continuous from bow to stern, visible without looking for it.

Design Goal

"Project a stable, level horizon line in enclosed ship spaces — passively, reliably, without disrupting crew workflow."

05 — Scientific Foundation

Grounded in Research

Decades of peer-reviewed neurophysiology and vestibular science. Click any card to read more.

01

Sensory Conflict Theory

Oman (1990) · Reason & Brand (1975)

Motion sickness arises from asynchronisation between visual and vestibular cues. The brain expects aligned signals — conflict produces nausea.

Directly addressed by introducing a stable visual anchor
Reason & Brand (1975) laid the foundational taxonomy of motion sickness. Oman (1990) formalised the neural mismatch model, demonstrating that the brainstem compares expected motion patterns against actual sensory input. When the difference exceeds a threshold, autonomic distress signals trigger — producing nausea, pallor, and sweating.
02

Visual Horizon Effect

Ebenholtz (1992)

Viewing a fixed horizon line significantly reduces seasickness symptoms. A true horizon reference is uniquely effective — arbitrary visual cues don't substitute.

Validates the horizontal line as the key design element
Ebenholtz found that participants shown a stable horizontal reference reduced self-reported sickness scores by up to 58% compared to controls. The effect was specific to a genuine horizon line — random visual patterns or vertical lines produced no significant benefit, isolating the horizontal axis as the operative variable.
03

Subjective Vertical Conflict

SVC Theory · Multiple Authors

The brain maintains an internal model of "vertical." Sickness occurs when visual vertical misaligns with actual gravitational direction.

Justifies the self-stabilising gimbal mechanism
The SVC model explains why tilted visual environments can induce disorientation. The brain continuously reconciles gravitational signals from the otolith organs with visual information. A gimbal-stabilised device maintains the projected line at true horizontal regardless of ship motion, directly resolving the SVC discrepancy.
04

Artificial Visual Cues (VR)

Keshavarz et al. (2015) · Duh et al. (2004)

Stable artificial visual references reduce motion sickness in flight simulators and VR — validating the principle beyond maritime contexts.

Extends proven VR results to the physical maritime space
Multiple VR studies introduced artificial horizon overlays and cockpit reference lines to reduce simulator sickness. Keshavarz et al. meta-analysis found consistent symptom reduction across 14 studies when a stable visual reference was present — directly supporting transplanting the intervention to physical maritime environments.
06 — The Solution

HorizonLine Projector

A self-stabilising gimbal device mounts to any interior wall. As the ship rolls, the outer chassis tilts — but the inner gimbal counter-rotates, keeping the projected horizon perfectly level. Drag the slider to feel it.

Status HORIZONLINE ACTIVE
Ship Roll 0.0°
0°

Self-Stabilising Gimbal

Gyroscopic sensors keep the projection perfectly level regardless of ship pitch and roll — up to ±25°.

Horizontal Light Emitter

A continuous warm beam acts as an artificial horizon — the visual anchor that resolves the sensory conflict.

Maritime-Grade Build

Compact wall-mount unit rated for marine environments. Fits corridors, galleys, and crew cabins.

Zero-Interaction System

Always on, entirely passive. Assists every crew member in the space simultaneously, with no user action required.

07 — Physical Prototype

Built & Tested

A 3D-printed gimbal mechanism proves the core concept: a self-levelling mount keeps the light emitter horizontal regardless of chassis tilt.

Working in Real Conditions — 6-step diagram showing ship motion detection, gimbal stabilisation, and horizon projection, plus component breakdown of gyroscope, stabilising weight, light emitter, and wall mount
System Overview

Six-step mechanism from ship motion detection to stable projected horizon, with component breakdown: gyroscope, stabilising weight, light emitter, and wall mount.

HorizonLine device installed in ship kitchen, corridor, and crew cabin — showing the projected horizon line across each space
Concept Visualisation

HorizonLine deployed across three ship environments — galley kitchen, crew corridor, and sleeping cabin — each receiving a continuous level reference line at eye height.

3D-printed HorizonLine prototype — three views showing the black cylindrical body and red gimbal ring
Physical Prototype

3D-Printed Gimbal Mechanism

The core of the prototype: a black cylindrical projector housing suspended inside a red gimbal ring. As the chassis tilts with the ship, the inner mass stays perfectly level under gravity — validating the stabilisation principle without any electronics.

  • PLA body + ABS gimbal ring
  • Passive gravity self-levelling
  • Directional light aperture (front face)
  • Wall-mount bracket integrated
Ship kitchen interior with HorizonLine device mounted on wall, projecting a warm horizontal light line across the space
In-Context Render

Deployed in a Ship Kitchen

The device mounts flush to the wall. Its projected line runs the full length of the galley at eye level — giving the cook a stable visual anchor as the ship rolls. Zero disruption to the workspace; zero crew interaction required.

  • Wall-mounted, zero floor footprint
  • Warm-tone projection blends with ambient light
  • Always-on passive system
  • One device per 6–8 m of corridor

Prototype Validation

The mechanical gimbal successfully demonstrated passive self-levelling across ±25° of tilt — matching the roll envelope of most passenger vessels in sea state 4–5. The next iteration will integrate a laser line diode and real-time gyroscope active correction for precision below ±0.5°.

08 — Live Demonstration

See It In Action

The HorizonLine projector maintains a perfectly level visual reference as the vessel rolls — eliminating the sensory mismatch that causes motion sickness.

Prototype · Passive Gimbal · ±25° Roll
01

Ship Rolls

The vessel hull tilts with wave motion — the enclosure loses all visual stability reference.

02

Gimbal Compensates

Gravity acts on the counterweight, passively rotating the projector head back to level in real time.

03

Horizon Stays Fixed

The projected line remains horizontal on the wall — giving the brain a stable anchor regardless of tilt.

09 — UX Flow

How It Works

From sensory conflict to restored orientation — four steps, zero user effort.

1
Trigger

Sensory Mismatch Begins

The ship moves. Inner ear detects it. Eyes see a static windowless room. Neural conflict initiates nausea.

2
Intervention

HorizonLine Projects a Stable Reference

The gimbal device projects a perfectly horizontal line onto the wall — always level, always there.

3
Response

The Brain Finds Its Anchor

The stable line allows the brain to reconcile vestibular and visual inputs — the conflict signal drops.

4
Outcome

Orientation Restored, Work Continues

Nausea subsides. Crew continues working. No interruption, no wearable, no workflow change.

10 — Design Evaluation

Strengths & Limitations

An honest assessment — where the design excels and where careful implementation matters.

Passive System

Zero user interaction. Works continuously in the background without cognitive demand.

Scalable Coverage

One device assists all crew in visual range — unlike personal solutions like wristbands.

Non-Intrusive Integration

Mounts into existing interiors. No wearables, no training, no workflow change.

Scientifically Grounded

Directly translates validated research into a practical, deployable product.

Visibility Dependency

Requires clear line of sight. Crowded galleys or narrow corridors may limit coverage.

Lighting Conditions

Needs sufficient contrast. Bright lighting may require adaptive brightness control.

Calibration Precision

High-precision gimbal stabilisation is essential. Any drift reduces effectiveness.

Individual Variation

Response to visual cues varies. The solution may not be equally effective for all crew.

11 — Impact & Implementation

Expected Outcomes

From immediate crew relief to scalable B2B maritime product.

0
Deployment Zones
Galleys · Corridors · Quarters
0
Crew Roles Protected
Galley · Housekeeping · Service
0
Target Sectors
Cruise · Cargo · Submarines

Galleys & Workspaces

Constant orientation cues during food prep and service

Corridors

Anchors at key junctions benefit mobile crew throughout

Sleeping Quarters

Accelerated recovery during rest between long shifts

Future Development

Adaptive Brightness
Multi-line Depth Cues
Ship-wide Sensor Sync
B2B Cruise Licensing
Cargo & Submarine Variants
Clinical Efficacy Trials
12 — References

Academic Sources

Real, widely-cited research underpinning the HorizonLine concept.

Core Motion Sickness

Reason, J. T., & Brand, J. J. (1975). Motion sickness. Academic Press.

Oman, C. M. (1990). Motion sickness: Sensory conflict theory. J. Vestibular Research, 1(1), 1–15.

Golding, J. F. (2016). Motion sickness susceptibility. Autonomic Neuroscience, 129.

Visual–Vestibular

Bertolini & Straumann (2016). Moving in a moving world. Frontiers in Neurology, 7, 14.

Ebenholtz, S. M. (1992). Visual horizon in motion sickness. Perception, 21(4).

Stoffregen & Smart (1998). Postural instability precedes sickness. Brain Research Bulletin.

Artificial Visual Cues

Keshavarz et al. (2015). Vection and motion sickness. Frontiers in Psychology, 6, 472.

Duh et al. (2004). Conflicting motion cues in visual environments. Aviation, Space & Enviro. Medicine.

Keshavarz, Hecht & Lawson (2014). Visually induced motion sickness. Handbook of Virtual Environments.