An original engineering approach developed at the Technion enables the building of light and durable speed boats suited to rough seas; experiments conducted on new research boat Dganit validate this approach
An innovative research vessel has been developed at the Technion to test a novel design approach. Technion scientists built the speed boat to test their new design procedure that makes it possible to significantly reduce the vessel’s scantlings – the dimensions of the frame – thus reducing its weight, increasing its speed, and reducing its fuel consumption.
The new vessel, named Dganit, merges “traditional” design with the new approach: its port side complies with standard design rules, while its starboard side is constructed using the new method.
Technion President Prof. Peretz Lavie said: “I don’t know how many of you know, but during the 1930s Technion had a nautical school, because Haifa is a port city. The Technion started by helping to design ships and to construct boats. Here we are closing a historical circle. Technion researchers joined forces with industry to build the Dganit – a new boat made out of new materials, based on new engineering principles, that will be lighter, faster and durable. I am very proud of Technion achievements.”
Dganit was designed and built over the past three years by Profs. Nitai Drimer and Daniel Rittel from Technion’s Faculty of Mechanical Engineering; by Sela Ltd. and Sherman Carmel, two firms owned by Benny Danino; and by postgraduates Yahav Moshkovich, Or Neuberg and Oren Rijensky, the latter of whom is in a direct PhD program. The collaboration between the Technion and the two firms took place under the MEIMAD program for encouraging R&D of dual use technologies. (MEIMAD is a collaborative program between the Ministry of Defense, the OCS at the Ministry of Industry, Trade and Labor and the Ministry of Finance, to jointly promote new ideas and new technologies that can serve both commercial applications and military needs.)
“It was a complex, fascinating challenge,” says Rittel, head of Technion’s Materials Mechanics Center. “I’m not even a marine vehicle specialist, so for me it meant starting from scratch and ending up with an actual boat that supports our research. Israeli bravado – pushing the limits, challenging the system, thinking out of the box and not fearing failure – definitely played a major part here.”
The boat is the brainchild of Danino and Drimer. Speed boat design, explains Drimer, involves some trade-offs between the light weight needed for speed, and the strength needed to resist the force of the waves while cruising at high speed in the open sea. “The more knowledge and experience I gathered, the more I realized that existing design standards, set by classification societies, produce relatively heavy and robust vessels; but only as a researcher at the Technion did I manage to get to the root of the problem.”
After his appointment as head of the Naval Architecture Division at Technion’s Faculty of Mechanical Engineering, Drimer continued researching the topic with Rittel. Together with their students they developed their innovative approach that takes into account design aspects relevant to conditions of extreme stress at sea: dynamics, hydro-elasticity, and nonlinear structural effects and Dganit was born. A comprehensive series of tests with the vessel successfully verified the rational design procedure, which was discussed in two Technion Master’s theses as well as in a paper published this year in the journal Ships and Offshore Structures.
“The most common concept for speed boats,” explains Drimer, “is planing, where most of the boat’s weight is supported by hydrodynamic lift. Having so much of its mass outside the water reduces water resistance and speeds up the boat. The problem is that in rough seas, planing exposes the hull to great slamming pressure by the water impact.”
Conventional practical design – based on classification society standards – treats the slamming pressure as quasi static, a premise that according to Drimer does not reflect reality when dealing with elastic structures. “We take a more complex, exact approach to wave-boat interactions, based on a design philosophy, an algorithm and analytical tools we have developed.”
The starboard side of Dganit incorporates advanced materials that make it largely fail proof. The technology, currently being patented, was developed by Rittel in collaboration with Sela Ltd.
“The boat has proved its practical value – that is, validated our design,” says Drimer. “This design is suitable for racing, rescue, intercept and other fast boats. Next, I intend to approach a classification society and propose developing a new standard. If we succeed, we can expect to see many boats built in accordance with our approach.”
Slide Photo: Boat Developers team. standing (L-R) : Oren Rijensky, Or Neuberg. Sitting (L-R) : Prof. Nitai Drimer, Prof. Daniel Rittel, Yahav Moshkovich
Photo by: Nitzan Zohar, Technion Spokesperson’s Office