SUP Safer

Making paddleboarding risk easier to understand

SUP Safer was my final-year dissertation project at Swansea University, a software application designed around a simple question:

Could technology help paddleboarders make better-informed decisions before heading onto the water?

Stand-up paddleboarding is an accessible way to explore coastal and inland environments, but that accessibility can also make it easy to underestimate the risks involved. Weather, wind, tides, local hazards and individual experience can all influence whether a planned trip is appropriate.

Rather than attempting to replace existing safety advice, I wanted to explore whether relevant environmental information could be brought together into a single, accessible application that helps users better understand the conditions they may encounter.

The result was SUP Safer: a location-focused application that assesses environmental conditions and communicates the associated risk through a simple visual interface.

The problem: fragmented safety information

One of the biggest challenges I identified during the early stages of the project was that safety information is often fragmented.

A paddleboarder planning a trip may need to consult several different sources, including weather forecasts, wind direction, tide times, local hazards and general safety guidance. The information itself may be available, but bringing it together and understanding what it means for a particular location can be less straightforward.

This is particularly important for less experienced paddlers. A forecast showing calm conditions does not necessarily mean that a location is suitable, while a seemingly small change in wind direction can significantly affect a coastal trip.

The RNLI's guidance highlights the importance of preparation, including checking weather and tide information, understanding the local environment, carrying a means of communication and using appropriate equipment.

This became the foundation of my project:

Rather than simply providing more information, could an application present important safety information in a way that makes the associated risks easier to understand?

Turning environmental data into a risk assessment

A central part of SUP Safer is its colour-coded, traffic-light risk classification system.

The application retrieves weather and marine data for Swansea Beach and assesses key environmental factors, including wind and wave conditions, alongside tidal considerations. These factors are evaluated independently before being combined into an overall risk classification.

The underlying model uses a non-compensatory approach: the most severe individual hazard determines the overall risk. A favourable condition cannot simply cancel out a more dangerous one elsewhere.

This was an important design decision. An average score could potentially make a combination of otherwise favourable conditions appear acceptable despite one significant hazard. By retaining the highest severity, the model takes a more conservative approach to communicating risk.

The resulting classifications (Low, Medium, High and Very High) provide a clear visual indication of the assessed conditions, while supporting users in making more informed decisions.

Research, guidance and visual communication

The project was not just about retrieving data and applying thresholds. I also investigated how existing safety guidance and visual interfaces could inform the way risk is communicated.

Beach flag systems provide a familiar example of how colour can communicate important safety information quickly. Similar visual principles are used in other settings where people need to interpret conditions or warnings without having to process large amounts of technical information.

I explored how these principles could be applied to paddleboarding, using a traffic-light interface to make the assessment easier to interpret at a glance.

The design complements established safety guidance rather than replacing it. A classification cannot capture every local hazard or individual circumstance, so the application is intended as an additional source of information, not a guarantee that conditions are safe.

Engineering and verification

SUP Safer was built using React and Tailwind CSS for the frontend, with Python and FastAPI powering the backend.

The backend integrates external environmental data sources and applies the risk classification rules, while the frontend presents the results in an accessible, responsive interface.

A particularly important part of the development process was verifying that the risk model behaved as intended. I used Alloy to exhaustively explore the model's possible states, alongside automated tests to check the implementation.

This allowed me to investigate the logic behind the classifications rather than relying solely on testing a handful of example scenarios.

The project also involved working with external data dependencies, designing a clear separation between the assessment logic and the user interface, and considering how the system should communicate its results to non-technical users.

Evaluating the result

SUP Safer was evaluated through a usability study involving 17 participants and achieved a System Usability Scale (SUS) score of 92.05/100.

This provided encouraging evidence that the interface was easy to use, while giving me an opportunity to evaluate the application beyond its technical implementation.

The project brought together full-stack development, environmental data integration, formal verification, safety research and user-centred design to address a practical problem.

What's next?

The current application focuses on Swansea Beach, providing a foundation for expanding the system to additional locations in the future.

Developing SUP Safer taught me that building a useful application involves more than implementing functionality. It also requires understanding the problem, evaluating the reliability of the underlying logic and presenting information in a way that people can actually use.

Explore the live application: sup-safer.co.uk