The Design Challenges Associated with Coating Ships

The structural design of ships has conventionally sought to seek an appropriate balance of requirements with respect to strength, weight, operation, ease of construction and cost whilst still complying with Classification Society rules concerned with the safety of the vessel.

In merchant ship structural design there is an emphasis on seeking designs with reduced complexity and inherent work content to facilitate ease of production and further exploit the increased utilisation of automation techniques and advanced modular outfitting. These first cost related objectives have been conventionally balanced against structural weight to identify ‘optimal’ weight-cost solutions. The issues of ease of application and reliability of coatings has not conventionally be considered as part of this trade-off but there is an increasing need for it to be included due to the introduction of the new IMO Performance Standard for Protective Coatings.

The IMO Performance Standard for Protective Coatings has led to a greater need to focus on identifying and quantifying suitable coating products and consideration of whether current structural designs are actually capable of being coated efficiently and reliably. The IMO PSPC highlights this issue in section 3.3.2, where it states that “the coating performance can be improved by adopting measures at the ship design stage such as reducing scallops, using rolled profiles, avoiding complex geometric configurations and ensuring that the structural configuration permits easy access for tools and to facilitate cleaning, drainage and drying of the spaces to be coated” The related issues of ensuring suitable qualifications of the inspectors who will manage and audit the process and the collection of data  and management required within the Coating Technical File also need to be addressed.

The aim of this paper will be to review the issues that should be considered at the design stage to better enable the more reliable coating of ships structures using the current coating technology available and to identify areas of possible research to improve the process through the potential adoption of novel structural configurations that will provide further benefits for the application of coatings and their subsequent reliability. Any proposed changes will not be considered in isolation, but will be balanced against other aspects of structural performance and cost.