For the 2020 edition of the Vendée Globe, SCAIME has participated in the implementation of optical strain gauges on the foils of Initiatives-Coeur sailboat.
Initiatives-Coeur is one of the racing boats in the IMOCA class whose length is regulated at 60 feet. Built in 2010, she has already completed two Vendée Globe races (finishing 2nd and 3rd) and is skippered by Samantha Davies for the 2020 edition. A British national, Samantha Davies has already completed more than 25 transatlantic races and 3 complete world tours. She has been at the helm of Initiatives-Coeur since 2017.
SCAIME and its local partner ARM, based in Nantes, provided the fiber optic strain measurement system and assisted the Initiatives-Coeur technical team for the sensor implementation.
For the Vendée Globe, the boat has been thoroughly modernized with, among other things, new foils. Larger and more efficient, these new foils increase the boat's performance.
The foils are the appendices installed on each side of the boat, in the center of the hull. When the boat gains speed, the hull leans on the lower part of the foils, lifting up and presenting less resistance to the water, which allows to increase the speed up to 30 nautical miles (55km/h).
The use of foils is very recent. If their efficiency in racing is undeniable, they have shown some weaknesses due to the very high strain imposed by offshore racing. To increase performance and reliability, the shapes and dimensions of foils are constantly evolving (the new foils of Initiative Coeur are similar to the wings of an albatross).
The design team's need is to validate, directly at sea, the behavior of the foils in correlation with other parameters such as wind, sea conditions or boat speed. For the skipper, the measurement system must be able to control the forces, measure in real time the power applied to improve performance and safety while sailing.
Considering the constraints of the marine environment, the choice naturally turned to the use of optical fiber which offers the robustness and the necessary integration capability for the application.
For each foil, the measurement of deformation is carried out by an optical line equipped with Fiber Bragg grating strain gauges. Each optical line, integrated in the foil, is connected to a SCAIME MDX400 optical measurement unit which converts in real time the optical measurements into digital data to be processed by the onboard navigation system.
The idea is to use sensors to measure the deformation of the foils while sailing. All the data collected is recorded by the navigation unit to read it live during the navigation. The goal is also to perform a post-processing work to analyze these data and see the stresses of the foils in all conditions encountered by the boat.
On-board electronics specialist