Making Stockholm’s ferries more efficient with Lohmega AB

How do you modernize a century-old system for directing passenger ferries around a series of islands?

That’s the question that faced Lohmega AB, Stockholm-based innovators who set about finding ways to harness the power of IoT to make ferry routes more efficient

Stockholm’s archipelago is a vast network of some 30,000 islands, islets, and skerries stretching out into the Baltic Sea, offering everything from lively inhabited islands to quiet, untouched nature.

Because the islands are spread over a wide area and many have no bridges to the mainland, ferries are an essential part of everyday life. Regular commuter-style boats carry locals to work, school, and errands, while larger ferries help tourists explore popular destinations, beaches, hiking trails, and charming village harbors. Together, these routes form a transportation system that keeps the archipelago connected year-round.

For over a century, passenger ferries have relied on a system of mechanical semaphores to signal when someone is waiting to board at a stop. These semaphores would signal to ferry drivers who would dock, before moving on to check the next point along the route.

This, though, is not particularly efficient. These semaphores can be difficult to see clearly in fog, rain, snow or at night – and the archipelago is particularly susceptible to low-lying fog in the colder months.

That’s where Lohmega AB came in. Their innovative new base station, powered by Saft, is changing how Stockholm’s ferries operate and helping to save significant amounts of fuel.

A commitment to bold thinking

Lohmega AB is a small Stockholm-based company with an interesting perspective. Their team of five engineers value freedom from which to select projects, emphasising the joy of learning new things through the development process.

Their works spans a wide range of applications, from radar systems and medical technology, to experimental creations as art producers (including autonomous robot beds that transport sleeping gallery visitors, and lamps that blow large soap bubbles).

Göran Nordahl, one of the founders of Lohmega AB explains, “We’re certainly not afraid of strange or bizarre projects, and I think it’s important for our team that we have fun and explore how we can use our skills differently. Working with artists and craftspeople is something we enjoy because it can help unlock new ways of thinking – and that’s an approach we tend to use in all our projects. It’s important to imagine what is possible with a project, and not be afraid of something failing either. For us, when we fail, we learn.”

For Göran, the question of how to improve the semaphores on Stockholm’s ferries had been a curiosity for well over a decade. Though he tried to garner interest in the project as a means of reducing fuel use, it was a renewed urgency on reducing the carbon footprint that sparked it into life.

The new creation sees each semaphore fitted with an accelerometer that detects whether the arm is raised and sends this information to a nearby base station. The base station then relays the status over LoRaWAN through The Things Network, allowing the semaphore’s position to appear on a digital timetable visible to the ferry captain.

With this system in place, the ferry can maintain an efficient speed along the route without detouring to every island to check for passengers. This improves fuel efficiency and lowers the risk of accidentally passing an island where someone is waiting.

The base station is powered by rechargeable Saft MP series batteries, and durable solar panels that are designed to survive the often-challenging Scandinavian climate.

“That’s one of the key reasons we opted for Saft batteries,” continues Göran. “We need to have that reliability when the weather is at its worst, and knowing that our stations will be powered at those sub-zero temperatures is vital.”

Images credit: Lohmega AB

Potential to gather more data

The new base stations underwent a pilot a few years ago and are now in being trialled more widely across the archipelago.

Though the exact amount of fuel saved varies depending on seasonal variations, tourism numbers, and driver choices – the amount is significant.

Now, the team are exploring how to add even more to the base station with a view to providing additional information to ferry drivers and passengers.

Per Göran, “There are a few potential sensors we’d like to add. We could add sensors for wind direction and speed as a safer way to gauge conditions than relying on the movements of tree branches or flags hanging from people’s flagpoles. We could also monitor water surface level to inform drivers of how choppy the waves are. These can be very helpful to drivers.”

“Then we could look at a temperature sensor to help people who are thinking about going for a swim, and we’ve considered adding a smart timetable into the base station itself, or even installing a game for waiting passengers!”

Whatever the next steps for the project are, with the team’s predilection for the unusual, it is likely to be a highly innovate addition to Stockholm’s ferry stops.