Engine Room
Sponsored By
Introducing
Tuna Drive
Is this the next breakthrough in
pod propulsion or a fishy story?
By Chuck and Lawrence Husick
Hydraulic rams powering the segmented “tail” sections allow the prototype Tuna Drive to deliver theoretical speeds of 35 knots.
Pod drives have revolutionized the technology of powerboat propulsion. The combination of horizontal propshaft angle, contra-rotating propellers and vectored thrust yield higher speed, greater maneuverability and significantly improved fuel economy, along with a significant reduction in noise and exhaust. The benefits of these drive systems, however, will soon be eclipsed by the new Propulsione di Tonno Coda (PTC) drive system being introduced by Scioccodiaprile, AG of Modena, Italy.
The new PTC drive resembles the IPS, Zeus and POD systems in its use of a controllable azimuth drive pod below the hull of the boat. However, the PTC drive has NO PROPELLERS. It relys instead on a thrust generation mechanism that mimics the propulsion of the fastest and most energy efficient fish in the ocean, members of the family Scombridae, (which includes the genus Thunnus), the giant bluefin tuna, which is known to achieve speeds of up to 36 knots over fantastically long distances, with minimal expenditure of energy. Working with faculty and students from an American college of engineering, Scioccodiaprile has truly crafted a “fish story” of great importance to the marine industry.
The remarkable performance achieved by the PTC propulsion system results from the hydrodynamic advantages of the shape and contours of the drive’s pod and the propulsion element, which combine to closely mimic a tuna’s swimming motions. The active part of the thrust system uses a vertically oriented articulated hydrofoil that bio-mimics the tail. The combination of the laminar water flow along the surfaces of this motori de mare and the wave-like, side-to-side motion of the “tail” deliver a continuous stream of rapidly moving water propelling the boat forward at speeds that range from barely perceptible to the maximum allowed by the available power and displacement. Continue Reading
