Published: 23.12.08
Focus project

Autonomously across the Atlantic

Eight mechanical engineering students have taken on something big: in the context of their focus project, they are designing a sailing boat to sail autonomously across the Atlantic.

Peter Rüegg
The SSA team from left to right: Hendrik Erckens, Patrick Schwizer, Gion-Andri Büsser, Stefan Wismer, Jürg Weber, Lian Giger and Patrick Moser. Sebastian Böhl is not in the photo.
The SSA team from left to right: Hendrik Erckens, Patrick Schwizer, Gion-Andri Büsser, Stefan Wismer, Jürg Weber, Lian Giger and Patrick Moser. Sebastian Böhl is not in the photo. (large view)

Design drawings showing various views of a sailing boat hang on movable walls in the LCE workshop, and a model – which would also not look out of place at bathtime – stands on the table. However, the seven mechanical engineering students out of eight who are gathered together in the workshop on Leonardstrasse on a Friday before Christmas are not in a mood for playing. The aim is for the plan to be transformed in early summer 2009 at the latest into a four metre ocean-going sailing boat weighing a maximum of 500 kilograms. This boat is intended to sail autonomously and unmanned from Ireland to the Caribbean, covering a total of 7,000 kilometres in three to four months. That would be a world record.

High-tech against primeval forces

Big challenges await the boat, named “Castor”. Storms, high seas, intense sunlight and corrosive seawater – all of these must be taken into account by the students in their planning, design and implementation. The sailing boat will be a high-tech product.

The deck will be fitted with solar cells to supply electricity for the on-board electronics, satellite communications and to control the rudder and sail. The electricity supply is backed up by fuel cells. These will be brought into operation when the solar panels are not supplying any current and the battery is exhausted. The students calculate that 50 kilos of methanol should be enough for the three to four month crossing. Ideally, the solar panels will charge a lithium-manganese battery to such an extent that it can deliver enough energy at night to keep the boat on course. To save weight, the students abandoned their original idea of using lead-acid accumulators.

Numerous sensors record important parameters 24 hours a day, such as wind speed and the heading and position of the boat. The data are transferred to a central computer in the hull, which processes them and also controls the position of the rudder and sail.

Lightweight and strong

The hull must be very strong and lightweight at the same time, so the students decided to fabricate this part of the boat as a sandwich structure of glass fibre and layers of PVC foam. The hull is also designed to include an area which contains the engine and electronics and which must remain free from water at all costs. The rigging and keel are made from carbon fibre. The keel bulb will be packed with 170 kg of lead to guarantee that the boat will be self-righting.

Another problem is the force transfer from the mast to the boat. Gion-Andri Büsser, who together with Hendrik Erckens leads the “Students Sailing Autonomously” (SSA) project team, says that the structural mechanics must withstand gigantic forces. To avoid lines getting tangled, the students have developed an unconventional rigging, known as an aero-rig, which has no lines at all. This makes the boat less prone to faults and lowers energy consumption. The sail will also be disengaged automatically if excessive torsion forces, which could damage the engine, occur on the rigging.

Boatbuilding as a teaching session

The whole project costs about 120,000 Swiss francs, mainly materials costs. This is why the students also depend on industry sponsors and have already kindled the enthusiasm of the “Sensirion” company, an ETH Zurich spin-off, as well as Accenture, an international management consultancy, as the biggest supporters of their project so far. The student sailing enthusiasts also have “EVEN AG” on their side, a company which designed the German boat for the Americas Cup, among others.

At present the SSA team is working flat out on their autonomous sailing boat. As indeed they must, for their schedule is very tight. They plan to christen their ship and launch it for the first time on Lake Zurich as early as March. The world championship for autonomous sailing boats takes place in Portugal in June, and it is expected that the world record attempt will finally be tackled in the autumn of 2009.

Presentation in late May 2009

Focus projects are available to students in the third year of their Mechanical Engineering Bachelor’s programme. The students have one year to plan, design and implement a project idea from beginning to end. They have fewer lectures to attend during this time. One example of a focus project is the “Maloja” student racing car which has taken part successfully in the Formula Student class at various competitions this year.

The aim of a focus exercise is not to obtain a perfect product but to carry out a demanding technology project and to complete the development process, while at the same time developing their team, defining hierarchies and organisation and resolving conflicts. Professor Roland Siegwart, the students’ supervisor, says “The students must search for and implement solutions to their problems independently. However, he says the students would take the important decisions themselves and would also have to bear their consequences.

Other focus projects currently ongoing include “naro”, a robot fish, the Disney-Copter and the “Pegasus” hybrid sports car, which is intended to give new momentum in the automobile area through new developments. The projects will be presented to the public during the “roll-out” on 26 May 2009.

Reader comments: