NavalHead, naval and nautical design firm, directed by Andrea Agrusta, has made hydrodynamics its mission for over 7 years. The team is made up of young dynamic naval engineers who work hard on each project to come up with something distinct and innovative that makes the difference
by Camilla Bianchi
Ever since he founded NavalHead, Andrea Agrusta has always had a clear idea of how to design an efficient hull. «Over the years we’ve designed all kinds of boats, but our design approach has always been different to the standard because our starting point is always hydrodynamics».
NavalHead can now boast partnerships with the main shipyards in the industry, with an especially varied portfolio of designs produced or being built, including high-speed powerboats, yachts with displacement and semi-displacement hulls, jet skis and mini-submarines.
The common thread? Highly-technological designs and special focus on hulls, tailoring the ever-increasing requirement to entirely and efficiently reduce energy consumption and pollution, without giving up speed and comfort.
«A designer has to be an innovator first and foremost», states Fabio Marzulli, who has been the director of the hydrodynamics and propulsion department at NavalHead for over three years.
«Each design comes from the desire to create something new and different, with one word in mind – efficiency. This aim can only be achieved with a methodical approach to design and painstaking, detailed analysis. I’ve had the privilege of overseeing each design in its entirety and liaising with the various individuals who turn our designs into works of art», continues Marzulli.
«At NavalHead we don’t settle for the tried and tested, we continuously strive to introduce cutting-edge solutions and unusual underwater shapes, such as the new Wake38D design, a 38-metre displacement yacht with hybrid propulsion technology and CFD hull optimisation that offers high energy efficiency. We worked a lot on the bow and stern sections in this design, analysing different bulb, trim-wedge and wing transom combinations in an attempt to offer special shapes which eventually gave the desired effect».
The basic hull had the typical shape of a displacement hull i.e. round bilge with a skeg and no chine or rails. Once the required speed range was identified, optimisation started by testing a set of bow bulbs until the best solution was found for generating an anti-phase wave designed to reduce resistance.
A stern trim wedge was then designed to calibrate attitude and improve wake in the propeller area. The hydrodynamic analysis didn’t just involve the hull and keel but also self-propulsion, pressure around the propeller and the wake, with hydrodynamic optimisation that considers the efficiency not just of the hull, but also of the hull-keel-propeller combination, preventing flow interference and ensuring the best water flow to the propeller in the water.
«Seakeeping calculations were developed to assess variation in wave resistance and acceleration in different areas on the boat, and understand the optimum arrangement of interiors, maximising on-board safety and comfort», continues Marzulli. «This is another example of a different approach, because usually the general plans and internal layout constitute the first document produced, whereas in this case rooms were positioned in relation to comfort level in rough seas. This design dynamism and the desire to experiment and constantly offer alternative solutions is the most fascinating aspect of our job».