COUNTER ROTATING PROPELLERS WITHOUT COMPLEX SHAFTING FOR A FAST MONOHULL FERRY

摘要

In the year 1999 the German shipyard Blohm+Voss initiated a research project aimed at the further development of their "Fast Monohull" concept. It is intended to apply this concept to cruise liners and RoRo ships sailing at over 30 kts. The work was partially funded by the German government. Three different propulsion arrangements were proposed: (1) A conventional twin screw arrangement, (2) an unconventional twin screw arrangement with staggered propeller planes and with the propeller disks nearly touching, and (3) a counter rotating propeller arrangement with the forward propeller conventionally driven and the aft propeller driven by a downstream pod. HSVA (the Hamburg Ship Model Basin) designed the hull lines for all three arrangements and optimised these using CFD methods prior to performing model tests. The third arrangement was investigated in more detail. After the stock propeller tests, HSVA designed a pair of counter rotating propellers and tested them in the towing tank as well as in HYKAT (HSVA's largest cavitation tunnel). It can be concluded that this propulsion arrangement offers substantial savings in power without generating unduely high vibration excitation levels.