Innovative sensors - a future use for cruising sailors?

by Photonics/Sail-World Cruising on 19 Sep 2012 Wouldn't you like to know when your mast or your boom has reached its structural limits? Know BEFORE there are any tell-tale signs visible? BEFORE it falls on top of you? A new technology is in the pipeline that could provide that information in the future, according to a new experiments by Wolfgang Schade and his team in Munich.

The new fibre optic sensor system could alert crew members when a craft reaches its structural limits. Such a system is designed to measure in real time the oceanic forces that act on hulls, masts and sails.

For a cruising sailor the loss of major items in the middle of any ocean is a significant worry, and as far as racing sailors are concerned, you have to remember that only one of the six teams in the 2012 Volvo Ocean Race from New Zealand to Brazil reached its destination; the others were sidelined with 'technical problems'.

So while the big money will no doubt be put to solving the problem for racing boats, what a boon it would be for cruising sailors. A fibre optic system fitted to a yacht could warn sailors of structural weak points and let them know if their vessel is in imminent danger of breaking apart.

The sensor system, in development by Schade and his team in the Project Group for Fiber Optical Sensor Systems at the Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, in Munich, is well on its way to becoming a reality. The technology is based on integrating fibre Bragg gratings into glass fibre at defined intervals to alter the refractive index.

'With fibre optic sensors, we can detect delaminations and even cracks at any early stage – long before a part breaks or fails,' Schade said. 'All you need is a fibre optic cable, in which dozens of sensors can be fitted.' The equipment includes the sensors, an LED, a spectrometer and electronics.

Sailors will be able to access crucial structural data in real time with specially developed apps on their smartphones from any point on the vessel.

To demonstrate the system, sail manufacturer Dimension-Polyant fitted a web of glass fibers containing 45 measuring points to a mainsail and genoa on a boat in the sailing workshop of Jens Nickel, whom Schade met at a boat fair.

A test sai revealed that tension in the head, at the top of the sail, was greater than had been assumed and that the strain on some other parts of the sail was lower than expected. The sail maker adjusted the production process accordingly.

Schade’s next objective is to adapt the technology to competitive racing. 'We have now fitted sail battens with fibre optic sensors, which will help competitors in the future to find the optimal trim,' he said.

As with all of these developments, the technology will take time to trickle down to cruising world. But then, patience is a familiar requirement for the successful cruising sailor.