Corrosion control design and management for a newbuild Floating Production Storage and Offloading installation (FPSO) operating in certain benign regions, such as West Africa, China and Brazil, can provide significantly increased challenges compared to their North Sea counter parts. This is primarily driven by a number different environmental factors, such as relatively high ambient temperatures, humidity and cargo temperatures. Therefore, it is difficult to select a cost effective corrosion control design that addresses both the fabrication and operational aspects. This paper provides guidance on how to address the key corrosion protection design and fabrication issues and their corresponding impact on inspection, maintenance and repair during operation. Introduction Eventhough there are over 100 FPSOs operating worldwide, designing and implementing a cost optimal Inspection, Maintenance and Repair (IMR) system for a 20 year service still remains a major challenge. Primarily this is due to the fact that there is limited information available to facilitate the corrosion control design for a 20 year continuous service. Newbuilding FPSOs have traditionally been purpose built for harsh environments, such as the North Sea, with converted FPSOs dominating the benign regions, such as Asia, Australia, Brazil and West Africa. As a result previous newbuildings have been designed with a major focus on fatigue and ultimate strength. However, it is forecast that 90% of future FPSOs will be installed in benign regions, with 60% of these being newbuildings/1/. Although these regions may be benign from a wave climate perspective they can impose significant corrosion control challenges relative to their North Sea counterparts. This is primarily a function of increased ambient temperatures and humidity. Many of the current newbuilding 'mega' FPSOs will have production capacities in excess of 200,000 bopd and, therefore, any lost production time can have very significant economic consequences. Therefore, it is very important to design, implement and manage a proper corrosion protection design. This paper provides some background and guidelines to facilitate the cost effective corrosion control design for newbuilding FPSO hulls. Specifically the focus is on:Identifying and quantifying the dominating factors related to corrosion control,How to select a cost effective corrosion protection system based on a combination of corrosion margins, coating systems and cathodic protection,Fabrication inspection related to the desired corrosion protection system,Providing an operation inspection, maintenance and repair strategies for selected corrosion protection system,Introducing a new RBI tool for IMR control of coated areas. Corrosion problems for converted vessels operating in the same regions, e.g. Brazil and West Aftrica, are well documented and selecting a cost-effective corrosion protection system can be equally difficult. Although this paper does not address converstions specifically, many of the basic concepts are still applicable. Basic aspects of FPSO corrosion control For carbon and low alloy steel FPSO hulls there are three principal types of corrosion to be considered/2/:General corrosion,Pitting corrosion, including "in-line pitting attack" and "grooving corrosion", andGalvanic corrosion (e.g. at welds).

A large number of dry tree concept's have been proposed to the offshore industry over the last few years for application in deepwater fields in the Gulf of Mexico, West Africa and Brazil. Looking into the details of these concepts, they all to a varying degree apply new and unproven technology that will increase project risk when brought to first use.PGS Offshore Technology has over the last 3 years developed the Dry Tree Semi or DTS, which limits the cost and risk aspects of unproven technology by using a standard semi-submersible hull with top-tensioned risers suspended by large volume buoyancy cans. A Norwegian patent has been awarded, and US and international patents are pending for the riser support system developed for the DTS, which comprises a light weight truss tower placed in the centre of the hull. Conventional sliding or roller bearings provide lateral support to the buoyancy cans inside the riser support tower. The DTS concept avoids the disadvantage of dry tree concepts with riser tensioners, which rapidly loose payload capacity in deep water because of the increasing weights of the riser system. Compared to SPAR alternatives, the DTS has a substantially better steel weight to payload ratio. Also, installation costs are considerably reduced since offshore lifting and mating operations are not required.At the OTC 2000 (ref. /1/), a DTS platform concept for West Africa was presented. This paper presents a DTS platform concept, primarily for use in the Gulf of Mexico, but also suitable for deepwater applications offshore Brazil.

Wind energy is one of the key renewable energy sources that will make a significant contribution towards the goals of clean energy around the world. The offshore wind energy industry is in a period of rapid growth, which results in a massive demand on the current supply chain. The large scale development demands specific installation and maintenance vessels. Various wind turbine installation vessels are being designed or constructed with a combination of new and existing technologies. There are specific challenges and design considerations related to this kind of vessels. Understanding the critical design parameters and considerations for various design concepts of WTI units are important for proper selection of design and technical standards in order to ensure a safe and robust design. The industry needs new design standards developed with synergy from well established offshore/maritime practices to provide guidance for this new vessel type to meet the high energy demand and to ensure high safety standards in the offshore wind energy sector. The paper first presents examples of various types of Wind Turbine Installation vessels that currently are being developed and then describe how DNV rules and standards address the specific challenges and critical elements for these various types of WTI units to ensure a safe and robust design. The paper then goes on to describes some of the key parameters and methodologies by which selection of these various design concepts can be carried out for a particular project/application.

This article deals with the history of classification societies from their early establishment covering the needs of marine insurers to assess the condition of ship hulls to their current role within the maritime and offshore industry. Lloyd's Register of British and Foreign Shipping was reconstituted as a self‐standing “classification society” in 1834. Following the recommendations of the International Load Line Convention of 1930 for class societies to collaborate, a major Class Society Conference in 1955 led to the creation of Working Parties on specific topics and, in 1968, to the formation of International Association of Class Societies (IACS) by seven leading societies. “Lloyd's Register of British and Foreign Shipping” was reconstituted as a self‐standing “classification society” in 1834. Following the recommendations of the International Load Line Convention of 1930 for class societies to collaborate, a major class society conference in 1955 led to the creation of working parties on specific topics and, in 1968, to the formation of International Association of Class Societies (IACS) by seven leading societies. The classification is a system for safeguarding life and property at sea and the environment due to operational consequences, having a ‘cradle‐to‐grave’ approach, with an involvement starting during the design phase, continuing during the building at the yard and production of the installed machinery and systems, and with a follow‐up during the operational use of the unit. The class societies' involvement is expected take a third‐party role and thus to be impartial and independent from owner, yard, and other commercial interests.