This talk will discuss the three main groups of nickel-containing alloys commonly used in marine environments; copper-based alloys, stainless steels and nickel-chromium-molybdenum alloys. The talk will discuss the corrosion of all three groups and the practical limits of use. Some examples from the service will be used to highlight potential corrosion problems and how they can be overcome. In addition, the requirements to produce corrosion-resistant welds in all three groups of alloys will be discussed, again with examples from the service. Finally, the non-exclusivity of these alloy groups will be demonstrated by some service experience.