Hydrofoils & Yacht Racing

I’ve been intrigued in the latest designs in the Americas Cup sailing boats, should I say these new race boats are in reality levitating above the water to reduce drag and increase speed through the water. 

Hydrofoils have been in existence since the beginning of the twenty century and were based upon Bernoulli law or principle which states In fluid dynamics, that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid’s potential energy.

The principle is named after Daniel Bernoulli who published it in his book Hydrodynamica in 1738. Bernoulli deduced that pressure decreases when the flow speed increases.

Hydrofoils have been around in various guises for many years and were developed for the US Navy between the early 60’s and 80’s as Fast Patrol Hydrofoil Missile craft. The bridge was more like an aircraft cockpit with similar controls to an aeroplane.

Hydrofoil shapes and configurations are designed to create lift just like an aeroplane wing. 

I will use series of YouTube videos to illustrate how foils work and their direct comparison with an aircraft wing which creates lift to support the weight of the aircraft during flight.

https://youtu.be/bGtyR6Ah5xQ

Early hydrofoil boats & ships were designed and manufactured by aircraft companies such Gumman and Boeing. Hydrofoil design and control is extremely technical as well as their individual configuration this next video isn’t too technical but it will give you an or more basic idea of the technicalities of foil design and control.

https://youtu.be/BVuWXApdfdENext Video is an interesting but a much longer film about the fastest US Navy petrol vessel, at the beginning of the film the preflight checks you ‘d think you were in an aircraft cockpit.https://youtu.be/zQ2sSRBMPqsRather long video but military hydrofoils were really experimental ships I think the US Navy decommissioned PHM in the 90’s. Probably far too expensive to maintain and run.The Americas cup sailing race teams must invest lots of money in foil design with high tech carbon Fibre composite materials. They test the carbon fibre foils to destruction.https://youtu.be/RPB7g2iNZugA75 class are trialing in Sardinia at Cagliari, not sure if the racing starts in October 2019 or April 2020 at Cagliari? But it would a great series to watch on the water. https://youtu.be/CyGQb-E5vck High performance foil boat racing is a dangerous sport because these yachts are flying in reality and they’re moving at great speed and they can crash land or even capsize.   British Olympic champion Andrew Simpson died a few years ago when Artemis capsize causing him fatal head injures. Water is an unforgiving medium at high speed. Remember Donald Campbell and Blue Bird flipping on Conistan water in Cumbria.   Must be scary when they get out of control, don’t see anyone of the crew wearing safety harnesses during sailing competitions. Probably too dangerous when boat capsizes. Certainly pushing all the boundaries of the sport sailing! But all the crewmen know the inherent dangers of foil yacht racing.https://youtu.be/cg2-MOp45xs

This final video is about the New Zealand race winning team novel way of using leg power instead of arm power in controlling the foils telemetry. America’s cup race boat are more like formula one racing cars in their technical design and performance.

https://youtu.be/N7iZvcIOk7w