A boat in a stormy sea

An engineering method developed at the Technion enables the construction of light and strong fast boats adapted to rough seas; The method was verified in experiments on the new experimental boat - "Daganit"

A research boat developed at the Technion applies advanced design methods for fast boats. The main goal: to experimentally test a planning procedure developed by Technion researchers. This new approach makes it possible to substantially reduce the thickness of the bottom of the boat and its weight, thus increasing its speed and/or reducing its fuel consumption.
The new boat, "Daganit", reflects at the same time the "traditional" design and the procedure developed at the Technion; The left crossing is built according to an accepted standard, while the right part is built according to the new method - a light structure and a thin bottom.

Technion President Prof. Peretz Lavi noted that with the launch of the boat "Daganit" two circles are closed. "In the 2016s, a nautical school operated at the Technion, but it was closed in a short time. Now, in 1924, the Technion presents a new boat based on an innovative approach and innovative materials. Another circle is related to the words of Menachem Osishkin, who said in the opening speech of the Technion in XNUMX that 'basic research and practical research are two sides of the same coin'; The boat is the product of a successful connection between basic research and applied research, which is based on cooperation between the Technion and industry."

The boat "Daganit" was designed and built in the last three years by Prof. Nathai Dreamer and Prof. Daniel Rittel from the Faculty of Mechanical Engineering at the Technion; The companies Sela Ltd. and Sherman Carmel, owned by Beni Danino; And three are paying for a master's degree at the Technion: Yahav Moskovitz, Or Neuberg and Oren Rizinsky, who continues on a direct path to a doctorate. The cooperation between the Technion and the two companies was carried out within the framework of the Dimension program (for leveraging dual research and development) financed by the Ministry of Economy and Industry and the Ministry of Defense.

"It was a complex and fascinating challenge," says Prof. Rittel. “I'm not even a boat expert, so for me this was a project where we started from scratch and ended up with an actual boat that validates our research. There is no doubt that the Israeli boldness we are familiar with - pushing boundaries, challenging the system, thinking outside the box, not being afraid of failure - played a significant role here."
The idea for the development of the boat was conceived by Beni Danino and Prof. Dreamer. According to Prof. Dreamer, in the design of fast boats there is a "trade-off" between the speed, which requires as little weight as possible, and the need for a strong body that will withstand the pounding of the strong waves typical of fast sailing. "As I gained experience and knowledge in the field, I realized that according to the existing design standards, determined by classification societies, produces relatively heavy boats; But until I arrived at the Technion I was unable to get to the root of the problem," he says.

After his appointment as head of the marine engineering program at the Technion's Faculty of Mechanical Engineering, Prof. Dreamer continued to investigate the issue together with his faculty colleague, Prof. Daniel Rittel, who heads the Technion's Center for Mechanics of Materials. Here the two together with their students developed a new approach that takes into account the aspects relevant to extreme load situations at sea: hydro-elasticity, structure dynamics and non-linearity. Based on a new approach to rational design that they developed, the researchers designed an actual research boat, and thus the "Daganit" boat was born. A comprehensive series of experiments on the boat was crowned with success - verification of the rational design procedure, which was discussed in two master's theses at the Technion and published this year in the journal Ships and Offshore Structures.

"The most common concept for speedboats," explains Prof. Dreamer, "is planing. In this situation, the bulk of the boat's weight is carried by hydrodynamic lift. The fact that a significant volume of the boat's hull is outside the water reduces water resistance and speeds up the boat. The problem is that when the sea is rough, sailing in the surf mode involves strong slamming pressure on the hull of the boat."
The accepted practical design, derived as mentioned from the standards of the classification societies, refers to the aforementioned impact load as a static pressure - an assumption that does not reflect the reality when it comes to an elastic structure, according to Prof. Dreamer. "Our approach, on the other hand, treats wave-boat interactions in a more complex and precise way, and this is based on a design philosophy, algorithm and analysis tools that we have developed."

The right part of the boat "Daganit" was built with a combination of advanced materials that give it high resistance to failure - a development by Prof. Rittel with the Sela company, which is currently in the process of registering a patent.

"The boat proved itself from an applied point of view, meaning it verified our design," says Prof. Dreamer. "This is a design that is suitable for racing boats, rescue boats and other fast boats. Now I intend to contact one of the classification companies and suggest that they write a new standard. If we succeed in this, we are likely to see many boats built according to the approach we have developed."