Author(s)

S. Chakrabarti

Abstract

This paper investigates the stability problem of a single point mooring (SPM) system using a buoyant tower. In particular, the stability of an inclined articulated loading tower (ALT) concept is discussed. The interaction of this tower with waves and the resulting Buffings equation and Matheiu type instability are analysed. A wave tank test of a model of the inclined ALT and corresponding SPM was performed to demonstrate the instability problem. For larger waves the motion of the tower appeared chaotic and the transverse oscillation was observed to be large. The frequency domain analysis applicable to upright articulated tower was generally found to be conservative for ALT as well as the SPM except at the lower periods. The complete time domain solution explained the observed ALT oscillation in waves.

Keywords