Evolution of Design 8/28/2020
Viking leads the industry in every facet of yacht manufacturing, and it all starts at the design stage where Viking’s Design and Engineering Department pushes the boundaries of naval architecture while incorporating 56 years of experience and expertise. Creating new innovative models for our customers illustrates our commitment to "Lead Not Follow," a key component of the Viking Difference.

The evolution of the design process now includes Viking’s use of Computational Fluid Dynamics (CFD) software from the company Orca3D, which allows us to conduct "virtual tank tests." In-house CFD software gives our Design and Engineering team the ability to run numerous virtual trials for each of our new models to optimize their running surfaces for better performance.

“I’ve been here for 33 years, and the one thing that always impresses me is the advancement of the tools we use to design boats,” adds David Wilson, Viking’s Design Manager. “We started with drafting tables and lofting boards, and then moved into computer-aided design. Now with CFD we’re taking it to the next level.”

Previously, the design protocol called for building 1/12th-scale tank test models (created from Viking 3D Computer-Aided Design) and analyzing their hydrodynamics in a test tank at the Stevens Institute of Technology in Hoboken, New Jersey. A separate model would be created for each variation in deadrise or hull shape. “We’d build several of these models here at Viking and then drive up to Stevens for a week of testing,” says naval architect Joe Snodgrass. “It’s an excellent facility and is a very effective way to test your designs, but with CFD we are saving time and expenses and we’re able to easily create and test multiple design variations in-house. It gives us greater freedom and flexibility when creating designs for new boats and the ability to promptly fine-tune existing yachts in our fleet.”

The scope of the data collected through physical tank testing can be duplicated – and even expanded upon – with virtual tank testing using the CFD software. Both real and virtual tank testing make it possible to measure the total resistance, effective horsepower, heave (vertical rise of the center of gravity) and trim angle. But the CFD program can also analyze the pressure distribution across the bottom of the boat. “We can actually look at the shapes and see where we can make changes to the deadrise or to the chine distribution or to the strakes to increase efficiency,” says Joe. “We can make adjustments to the hull shape or the shape of the appendages, such as bow thrusters, hull tunnels and intakes. This ability to analyze pressure is a valuable additional tool.”

Viking’s use of the Computational Fluid Dynamics software for new yacht models began with the 58 Convertible and has been used to design the 38 Billfish, 38 Open Billfish and 46 Billfish. Viking has invested in a powerful computer that can complete CFD simulations in under eight hours. “CFD analysis is now an integral part of the design process,” says Lonni Rutt, Vice President of Design and Engineering. “It really allows you to define what works and what doesn’t work. Once you eliminate what doesn’t work, you can focus on the changes that are yielding the most positive results.”

The Orca3D program allows the Design and Engineering Department to schedule several virtual tank test simulations to run one after the other over the course of a weekend or several days. The tests on a particular hull can be done using different displacements, center of gravity positions and speeds. “The machine is always ‘cooking’ because we are constantly developing new product,” says Joe. “It’s pretty much running all the time. I’m constantly hitting the go button.”

CFD has other capabilities that Viking intends to utilize, such as analyzing aerodynamics to streamline a yacht’s topside structures for decreased wind resistance. “We can also run our current and legacy fleet through the CFD software so that when we design a new yacht similar in size to a pre-existing model we have comparable data,” says Joe.

The transition to CFD analysis marked the beginning of another chapter in Viking’s long-time relationship with the founders of the Annapolis, Maryland-based Orca3D – Larry Leibman, Bruce Hays and George Hazen. Their Orca3D Marine CFD system is comprised of their naval architectural software and SimericsMP CFD software. “We’ve customized Simerics’ CFD software for marine applications,” says Bruce Hays. “Viking was one of the first yacht companies to fully embrace CFD analysis as an in-house tool.”

Bruce and George first worked with Viking back in the mid-1980s when David’s father, Bruce Wilson, utilized the duo’s first software product called FastYacht. The relationship remained strong over the years, and Viking was quick to jump on the opportunity to work with Bruce and George – as well as Larry, who joined the group in 1994 – once again. Viking has provided Orca3D with highly valuable benchmark data (both model-size and full-scale testing) to “help validate their approach to the software and work with Simerics to fine-tune the marine template for CFD,” says Bruce. “Joe and Dave have given useful feedback on the user interface of the program, also, so this relationship continues to be a win-win.”
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