Optimum design of miniature platforms for marginal fields

Motivated by many recent discoveries of marginal fields in deep water, this paper presents a novel and economical design concept of a minimal floating platform with around 10,000 cubic tons in displacement. The concept characterizes a simple hull geometry and an excellent seakeeping behavior. It incorporates a damping plate at the keel on the basis of a spar-like floater. The design procedure is explained and illustrated. The paper also describes a new design methodology that is capable of efficiently evaluating the seakeeping performance of the platforms with the viscous damping effect included. We integrate this methodology into an Evolutionary Algorithm (EA) to conduct a multi-objective optimization for our novel design. The hull shape is optimized by minimizing the heave motion in waves without sacrificing the cost in construction and installation. Several potential geometric configurations are considered. The optimization results provide a wealth of information that can be used to support practical design decisions.