An Experimental Investigation into the Effect of Bilge Keel Position on Landing Craft Utility Vessels

Abstract

The issue of energy efficiency in using fossil fuels and reducing the effects of greenhouse gas emissions is an urgent problem. So fuel-saving measures, including in the marine transportation sector, are needed, even if only by a small percentage. Landing Craft Utility (LCU) is a type of sea transport for defense matters that requires the addition of a rolling motion stabilizer for the safety and comfort of the ship, cargo, and passengers. The use of roll-damping devices can affect the increase in the resistance value of the ship and cause an increase in fuel consumption. The bilge keel is a roll-damping device that is suitable for LCU vessels. The experimental study roll decay tests and resistance tests were carried out to determine the effect of the bilge keel placement on roll damping and additional ship resistance. The flow around the vessel’s surface was observed with a paint smear test to determine the placement position. The bilge keel installed in the transitional position between the bottom and side hull has the highest total roll damping coefficient, up to 28.57%, compared to the bare hull condition. However, this placement has increased the average resistance up to 8.84%. Alternately, placement close to the draft line has a fairly good roll-damping coefficient of up to 21.27%, increasing the resistance to only 3.66%.