A concept for a ferry for the Gothenburg archipelago, where 190 people fly over the water at 30 knots using foil wings and batteries, resulting in significally lower energy consumption than that of today's ferries. This is the result of the work five Chalmers students did during the fall of 2023.
"If I had seen this result when the course started in September, I would have found it an incredibly interesting concept," says Per Mottram Hogström, researcher at Mechanics and Maritime Sciences, and examiner for the course.
In the Marine Design Project course, students are faced with challenges in ship design. Various companies contact Chalmers with requests to design a ship, and in 2023, the students were tasked with designing a ferry for the archipelago outside Gothenburg.
"Usually, the customer comes with a well-defined specification of what they want," says Per Mottram Hogström. "The students then try to meet the customer's requirements, see what is possible to do, by bouncing their thoughts and ideas with the customer."
The project culminates in the conceptual design of a ship, and in his office, he has several of models of concepts from previous years. The latest addition among the models arose from an idea that Per Mottram Hogström and his colleague Arash Eslamdoost had to create a ship that operates in the southern archipelago of Gothenburg, powered by electricity and so-called hydrofoil technology. Simply put, the technology involves equipping ships with foil wings. At a certain speed, the foil wings are deployed, lifting the ship above the surface. When resistance from the water disappears, the ferry's energy consumption drops drastically.
"The technology has been around for a long time and has boomed in recent years," says Per Mottram Hogström. "It's the high-performance racing sailboats in the America's Cup that have driven it. Today, this type of wings are found on all sorts of vessels, for example, motorboats and surfboards."
Own project proposal
The two researchers contacted Styrsöbolaget, which operates ferry traffic in the southern archipelago of Gothenburg, with the idea. They were told that the company was interested but had too much on their plate to devote time to the project. Per Mottram Hogström and Arash Eslamdoost chose to continue pursuing the idea anyway and formulated a project proposal for the students taking the course.
"We were instructed to build a foiling e-ferry for Västtrafik, not much more than that," says Marcus Varvne, one of five students on the course, about how he and his four fellow students were assigned the task.
The group tackled the task by starting with a week of brainstorming.
"We just sat and came up with a lot of ideas in our room, trying to figure out what kind of boat we wanted to look at – size, where it would operate, and so on," says Arvid Sörfeldt, one of the other students. “Piece by piece, things started to fall into place for us to examine more closely.”
"We had pretty clear boundaries in the project," says Marcus Varvne. "We had depth, width, height, and length, dimensions that we had to meet. If someone were to see the sketches we had after the first week today, they would probably think they were quite similar to the final result. But all of us involved know how many hours of work went into the final ferry.”
Smaller group – more responsibility
With a detailed sketch, the actual work of designing the ferry began. In the initial stage, the group created a "work preference sheet," a document listing each part of the project, and then each member indicated how much they preferred or didn't prefer to work on each part.
Since the group was small compared to previous years' student groups, the responsibility on each person was heavier.
"In previous years, there have been four groups with two to three specific people in each area," says Marcus Varvne. "We were only five, so we had to choose our own subarea to work on, and it became a big responsibility per person. It made it difficult to help others in the group."
"But it turned out very well in the end," says Arvid Sörfeldt. "Not everyone wanted to work on the same thing in the project, so we were a group that was well-suited for the task, and we had all the parts we needed."
The course and the work of creating the ferry concept lasted for 15 weeks in the fall. They mention time as one of the biggest challenges along the way. They set themselves clear short deadlines, "we should be done with this in two days," presented results to each other – which may not always have been the best possible, and they had to backtrack and redo.
"A lot has to fall into place and be connected for it to become a concept that functions as a whole," says Arvid Sörfeldt. "That's something I take great pride in, that we managed to pull it off."
They highlight trying new things and redoing as one of the biggest learning experiences along the way. Marcus Varvne describes that when you're designing this type of boat, the requirements in the process are very contradictory.
"There's no straight path forward. It's a balance between all the parts. For example, you want batteries, but at the same time, not too large batteries because they're heavy, and a foiling boat should be as light as possible. We could sit for a whole day and think we had the best solution, and then it wouldn’t work at all."
Creating something completely new, without repeating anything that has been done before, is one of the biggest rewards of the course. The results of the students' work will now be taken forward into a thesis project.
"We're doing something unique, we're making a new boat for a new customer," says Marcus Varvne. "In ten years, maybe our design and concept will become something, perhaps the basis for a real ferry, and that's very motivating."
About the course and the HSC Vinga
The goal of the Marine Design Project course this time was to create and design, as a group, a concept for a passenger ferry, powered by batteries and hydrofoil technology, that could operate in the southern archipelago of Gothenburg.
The students' concept ferry was named HSC Vinga, weighing just over 73 tons, 30 meters long, 8.4 meters wide, with a cruising speed of 30 knots. It is a catamaran ferry, built of carbon fiber-reinforced polymer plastic, with a capacity of up to 190 passengers and 20 bicycles.
The ferry has two so-called foil wings: a U-shaped foil in the middle of the ferry and a T-shaped foil at the stern. At a speed of 20 knots, the ferry lifts out of the water.
You can read more about the course, Marine design project, here.