Testing the limits of racing yachts
In yacht racing every second counts, and the relentless pursuit of extra speed has led boat builders to opt to use strong, lightweight composites. But although boats made of space-age materials have negotiated the most challenging seas, a manufacturing flaw in any component could have devastating consequences.
Carbon fibre has become a firm favourite of racing yacht designers to help make their boats go faster. But although it may appear perfect to the naked eye, it can in fact contain tiny flaws that could fatally compromise its strength or performance.
“Manufacturing carbon fibre is actually quite a manual process, with each layer being applied by hand, so problems can occur, such as air bubbles being trapped between the carbon fibre sheets,” says Charlotte Lovett, a racing yacht underwriter at Hiscox MGA.
These defects can only be picked up through non-destructive testing (NDT), which goes deep beneath the surface. Hiscox MGA has been conducting tests on the large racing yachts it insures since 2007, using several of the world’s top marine surveyors, and during that time has built up enormous experience of the use of cutting-edge designs and space-age materials on boats.
Revealing hidden flaws
Non-destructive testing covers a range of different techniques, including ultrasonics, bond testing, radiography, laser shearography, thermography and liquid penetrant testing. A trained surveyor would decide which technique to use depending on the type of material and construction of the component to be tested.
“If the NDT survey results reveal any flaws we will refer those back to the manufacturer to determine whether these are significant enough to affect the component’s structural integrity,” says Lovett. “Often, they’re judged to not be significant, in which case we monitor them regularly to make sure they don’t get worse.”
Unlike in the aerospace industry, where carbon-fibre components are tested to destruction – over and over again – before being fitted to planes, this only occurs at the very top end of yacht racing: the America’s Cup, where the stakes are so high that teams cannot afford foils and T-rudders to fail during the middle of a race, so eradicating any manufacturing faults is absolutely essential.
Elsewhere, carbon-fibre parts are made and fitted to racing yachts for immediate use in competition, which mean that production errors can creep in to components unnoticed, unless NDT is carried out. Testing can then be repeated at intervals to make sure everything is sound. “Regular testing means that we can benchmark and monitor any defects and easily pick up new problems that may have developed during a major race,” Lovett explains.
Peace of mind
NDT can offer racing-yacht owners the peace of mind of knowing that their precious carbon-fibre masts, which can cost up to £1 million, will be able to withstand the rigours of ocean racing. “If there is a problem then it would be better for the owner to know about it early so it can be fixed than for the mast to break during the middle of a race. Replacing it, and also repairing any damage it might have done to the hull when it came down, will cost a lot of money and could mean the boat is laid up for weeks,” says Lovett.
“Having their boats tested is in the owners’ own best interests. At the end of the day, it’s good risk management.”