Model Study of Cable‐Moored Conical Platform

Abstract

Cable‐moored platforms may be an attractive engineering approach to the problem of conducting engineering activities such as drilling in moderately deep (20–70 m) ice‐covered waters. However, the dynamic performance of such platforms in a variety of ice conditions requires further elucidation. This paper presents results of ice‐tank tests performed with a model‐scale platform and sheets of urea model ice. A total of 57 tests were conducted, the prime variables being ice speed and ice sheet thickness and plan dimensions, and stiffness of cable‐mooring system for restraining a platform. Forces increased monotonically with layer thickness. Resonance effects and the process of collar formation around the platform complicated the variation of forces with ice speed such that a clear trend of mooring forces with ice speed is not readily apparent. Mooring stiffness has a marked effect on resistance forces indicating that these forces may display a minimum value for model mooring stiffnesses of order 1 kN/m. Such findings have obvious practical import, and further work is needed in this area.