Researchers at the Universidad Politécnica de Madrid have developed a new technology based on composite materials and viscoelastic layers that increases the resistance of the hull of high-speed vessels while making them safer.
A speedboat that seems to fly across the water with big bangs - you may have seen them go by during a beach holiday or in an exciting action movie. The damaging effects of those hits can be significant; both for the craft itself and the passengers it carries.
Unlike large cargo ships that travel through the water, moving water in the process, there are also some ships that travel óver the surface of the water. Since these do not displace water, these vessels can also travel at much greater speeds. The speedboat is perhaps the best example of this. As the speed increases, however, the stem straightens out of the water only to fold back onto the water surface periodically. Because the water surface acts like a wall at these speeds, the hull of the craft has a hard time in the process. Also known as hull buckling, this phenomenon is a serious problem in high-speed vessels.
Frequent slapping of the hull causes damage to the boat, especially when made of non-organic fibres (glass, carbon) and composite polymers (polyester, vinyl). These composite materials, while lightweight, are also more susceptible to impact than, say, their metal counterparts. As a result of impacts on the water, the hull material becomes more fragile and miniscule cracks appear.
To protect the structure of high-speed vessels, Spanish researchers developed a new system in which thin viscoelastic bearing are inserted between layers between the composite material. This allows energy to be captured and dissipated. That energy is released when the vessel's hull keeps 'slamming' on the water surface. The layer is composed of ordinary hexagons of a stiff polymer encased in a light and viscoelastic material made of a specially developed rubber. Studies show that the repair frequency of damaged ship hulls decreases by a factor of three when the new technology is applied. Using the material for hulls not only contributes to a longer service life but also improves passenger safety. Shipyards, ship owners and classification societies have now expressed interest in the gradual introduction of this new development.
