A new wave?

Wave power is now being harnessed experimentally on quite a large scale to generate electric power, although it is far from obvious as to which technology is most cost effective. It is estimated that the worldwide useful wave power resource that might be harnessed is more than 2TW. Certainly, yachtsman are only too well aware of the dangers of waves driving them onto shore, and even large ferries stop sailing when waves are large enough to potentially drive them against harbour walls when making port. The biggest problem is that waves tend to drive boats where the wind sends them, which is often not along the course that sailors wish to follow. The second biggest problem is that mechanisms that translate oscillating motion into forward motion that rely on mechanics tend not to be very efficient. This means, apart from cost and complexity, average forward speed is not likely to be very fast, especially as progress is unlikely to be rapid in calm weather. The challenge Our challenge this month is to come up with a wave-powered vessel that is commercially viable. Boats are designed for users, whether their purpose is pleasure, war, or carriage of freight and part of the challenge is to come up with not only a design of wave powered vessel that is not only mechanically efficient and cost effective, but one for which relatively low average forward speeds are unimportant. Part of the consideration is that despite being slow, it must still be agile enough to avoid being run down by faster vessels, without having to have an auxiliary engine system. It is perhaps for these reasons that it is only now that a commercially viable wave powered vessel has become available. Prototyped and tested on a series of long ocean voyages, it has recently gone on sale, and the first production units have been found capable of performing vital tasks at a small fraction of the cost of conventional systems. The basic mechanics are quite simple, and are inspired by an idea that has been tried before. However, they incorporate a clever mechanical enhancement that greatly improves their efficiency while the electronics, on which it depends for its efficient functioning and survival, very much depend on the technologies of our age. The solution will be described fully in the June edition of Eureka. Solution to last month's Coffee Time Challenge The solution to last month's challenge comes from Jenton International, which makes, among other things, food packaging machinery. The 'Loose pack fruit bag' was originally conceived for cherries, and is made up from two pieces of plastic bag material. These are folded inwards at what is to be the top of the bag, and then sealed together in such a way as to leave an aperture sufficiently large for the hand. If the bag is turned on its side or inverted, anything inside tends to get caught by the plastic flaps that have been turned inside and then secured by the sealing. Jenton director Richard Little told us that, "There are lots of things you can do with it". He told us how his child took some Lego with him on a ferry, and how it proved invaluable in retaining those Lego bricks that were not required for the model, and how the bag could also be used to carry coins, spare parts, and screws and nails in such a way that they do not get dropped on the floor or factory car park. He also added that if you pour some beer in it and hang it upside down, the retained beer turns it into an effective wasp trap. The design is protected by patent.