Equipment faults and failures are generally tolerated more-so in maritime than in other transportation domains given the heightened safety-criticality of equipment onboard air and land vehicles as compared to sea-going vessels. As a result, ensuring availability of conventional vessel equipment can require bespoke and complex maintenance and repair tasks to be carried out particularly for long-duration operations. However, a future proliferation of Autonomous Surface Vessels (ASVs) demands a different philosophy to designing for availability without a conventional crew. This paper outlines the challenges to delivering equipment availability that are particular to ASVs, potential solutions and developmental work required. For long duration unattended operation, addressing “holistic” health is the paramount challenge so both structural and machinery related and ensuring hull, mechanical and electrical availability. To address this challenge, a structured, comprehensive and detailed upfront analysis of equipment faults using a suite of techniques and backed up by modelling and real-world data can be used to focus the design effort around high-probability triggers and high-severity consequences. Design efforts should then consider mitigations across the cause-effect chain and engineer-out single-points-of-failure whilst engineering-in fault recoverability e.g. degraded subsystems operating in concert with still healthy subsystems. For untrodden areas of equipment automation, what-ifs based upon common-causes of failures could help to plug knowledge gaps. Modern and emerging technologies could then be better exploited to augment condition monitoring such as IoT based sensors, drone-based inspection, machine-learning based prognostics and augmented reality. At the other end of the chain, the same can be said of equipment repair and replacement, where the full potential of onboard robots and 3D printing for example, remains to be understood. Turning to ASV equipment availability and without the benefit of access to unrestricted, unplanned human intervention, the relative pros and cons of the three prevailing maintenance strategies should be objectively compared to strike the best balance between: corrective maintenance, schedule-based/preventative maintenance, and condition-based/predictive maintenance. The three strategies fall on a continuum ranging from reactive to proactive where there is tension between cost and benefit, such as the lower expense but longer downtime for the former case compared to the higher expense but shorter downtime for the latter. Hence the need arises for an evidence-based assessment weighing up of the alternatives to target the “sweet spots” between them.