Dynamic Hull Vane—A Solution for Active Pitch Motion Reduction and Resistance Reduction of Ships

Abstract

_ The Dynamic Hull Vane® is an actively controlled version of the Hull Vane®, a patented energy-saving and seakeeping device which consists of a submerged wing mounted on the aft ship. The Hull Vane is positioned in the upward flow aft of the ship, to develop forward thrust and reduce the stern wave. Naiad Dynamics US Inc, is a supplier of ride control systems and has worked with Hull Vane BV to develop the Dynamic Hull Vane®. By enabling the Hull Vane® to rotate, it can produce variable lift forces which when suitably controlled can reduce the pitching motions of a vessel in a seaway. This paper describes some of the research carried out on the AMECRC series 13, a generic fast displacement hull. Introduction Among other characteristics, two main performance parameters of a ship are fuel consumption and ship motions. Besides a well-designed hull, several appendages can be used to increase the performance. One of this is the Hull Vane. The Hull Vane is a fixed hydrofoil behind the transom of the ship. The Hull Vane has the potential to create large lift forces on the aft ship, thereby changing the resistance and the dynamic position of the vessel (Uithof et al. 2014). Ship motion reduction has long been a topic of research, and this has led to a number of solutions, which are widely applied. Most of the study work and products have been related to the rolling motions of ships, and there are indeed various effective solutions available, such as fin stabilizers, gyrostabilizers, interceptors, trim tabs, and antiroll tanks. The pitching motion of ships has been studied less, and while there are systems on the market to actively dampen the pitching motions of fast (planing) vessels, it has always been a challenge to dampen the pitch and heave motions of displacement ships, due to their inertia and limited speed. The pitch and heave motions are the prime source of vertical accelerations on board and these in turn are one of the main contributors in the Motion Sickness Incidence (MSI). Passive systems to reduce pitch motions exist, such as bow foils, which are preferably retractable to avoid their resistance penalty in calm water. There are two passive systems which dampen pitching motions while not adding calm-water resistance on specific ship types, because they reduce the wavemaking resistance of the ship: the bulbous bow and Hull Vane®. The pitch dampening effect of the passive Hull Vane has been demonstrated on naval vessels in computational fluid dynamics (CFD) (Bouckaert 2016) and in model tests (Ferré 2019).