MARCS-An Integrated Computer System for the Analysis and Design of Marine Structures
Authors: Bridges J.W. 
Published: October 2008

ABSTRACT
An integrated system of digital computer programs called MARCS (Marine Structures Computer System) that is used for the design and analysis of marine structures is described in this paper. The system, developed by Synercom Technology, Inc., is presently being used by several companies in the offshore industry. MARCS has been used for the design and analysis of fixed offshore platforms, offshore terminal facilities, mobile jack-up drilling structures and semi-submersible structures.
MARCS consists of four primary subsystems referred to as AUTOPLAT, SEALOAD, STRAN and PILEAN. Each of these is responsible for one of the major data handling or analysis functions that is involved in the design or analysis of a marine structure. The subsystems are linked together with a data management system that permits a high degree of flexibility in the way that MARCS is used. The system operates such that the engineer can interact with various subsystems to perform different functions that are involved in the design and analysis of a marine structure.
This paper discusses the system design of MARCS and the operation of its various subsystems. The data management techniques used by the system are described as are the methods of structure description and modeling utilized in the AUTOPLAT subsystem. A discussion is included of the Coupled Interaction Capability of MARCS that permits an integral analysis of a fixed offshore platform with its linear superstructure and non-linear foundation. System operation is described in terms of the way an engineer uses MARCS to design and analyze typical kinds of marine structures.

1. INTRODUCTION
The design and analysis of marine structures requires the performance of a range of complex tasks that span several disciplines. It is generally recognized that the computer enables engineers to perform these tasks more effectively. By permitting faster, more accurate and more complete problem analyses to be performed, computers can serve as valuable tools to the engineer responsible for marine structures. However, as is the case with any of the tools of our technological society, there can be a wide variation in the degree of this effectiveness.
The engineer using the computer as a tool is not normally concerned with the machine itself, but with the programs that enable the computer to solve his particular problems. The engineer often uses the computer by means of a number of individual programs, each program responsible for performing one kind of calculation or one category of analysis. For example, the engineer might have one program he uses for wave calculations, one for stability analysis, another for structural analysis and perhaps several different programs for foundation analysis. Use of individual programs involves a great deal of effort in taking results from one and putting the results, along with other data, into another. Due to the complexity of each of these programs, the engineer has often found it quite difficult to coordinate this data and properly consider all of the interactions involved. Many of the feedback aspects of a problem had to be overlooked.