13 January 2006
13 January 2006
The Earthrace project has been established to break the outright world record for circumnavigating the globe in a powerboat, and uses DIAB cores in its composite hull structure.
A key element of the record-breaking strategy is to run the boat continuously at high speed (up to 45 knots) in rough as well as flat sea conditions. To achieve this, wave piercing technology has been employed together with sponsons to provide additional stability. As can been by the 3D CAD model above, the Earthrace vessel has a very fine bow with minimal reserve buoyancy in the forward portions of the hull to significantly reduce vertical motions.
When a wave is encountered, the hull pierces through the water rather than riding over the top. Although this can look very dramatic to the onlooker as the vessel submarines through the wave, the ride is much smoother than more traditional deep-V designs, minimizing the stress on the vessel as well as the crew.
The 24 meter (78 ft.) long boat is in the final stages of construction at the Auckland, New Zealand yard of Calibre Boatbuilders. She was built using a ‘moldless’ strip plank method where the DIAB core is applied in the form of planks to temporary frames to create the hull shape.
The strip plank technique is a very cost-effective and fast method of producing a one-off boat as it dispenses with the need for a mold. In principle, it involves setting up a series of transverse frames and/or bulkheads. Core ‘planks’ are then attached to the frames thereby creating the hull shape. Following fairing, the outer skin reinforcements are laminated into place. The hull is then rotat¬ed 180°, any temporary frames are removed and the inner skin reinforcements are applied.
In the case of the Earthrace a somewhat different methodology was used as the hull was produced as two half moldings. Basically a ‘female mold’ approach was taken. Again frames were set up and the DIAB core ‘planks’ were applied. Then the inner skin carbon reinforcements were laminated into place. The half hulls were then joined together longitudinally, the boat was rotated and the outer skin laminates were applied.
To speed the planking pro¬cess and to reduce filling an fairing, the DIAB foam core ‘planks’ can be supplied with a convex profile on one long edge and concave profile on the other.
Achieving the circumnavigation by only using bio-diesel renewable fuel, the Earthrace team are also hoping that the high profile nature of the project will significantly raise awareness about the use of sustainable resources.
Circumnavigating the globe represents the pinnacle of powerboat challenges. At 24,000 nautical miles, it is the world’s longest race. The current record of 75 days was set in 1998 by another DIAB-cored vessel, Cable & Wireless. According to the Earthrace team’s calculations, they expect to smash the existing record by at least five days, completing the voyage in less than 65 days.
Cobra International is celebrating its 40th year and has commissioned a book that will look at 40 key projects and 40 key people that were integral to the company’s growth. ‘Klaus Simmer and The King Cobra: A breakthrough in surfboard design and production technology’ is an extract article from this book and a breakthrough composites product for Cobra, establishing its presence as a manufacturer of high performance windsurf boards and creating global visibility for the Cobra brand.