machinery maintenance

Finding the right machinery maintenance system for ship owners


For ship operators to sail safely – and in compliance with the International Safety Management (ISM) Code – their vessels must undergo regular inspections of their machinery equipment and systems. However, most modern ships have more than 300 separate pieces of machinery onboard, each with its own specific maintenance requirements. This poses a challenge to ship owners and operators: how to conduct machinery maintenance regularly, but also efficiently in terms of time and cost?

According to the ISM Code, all ship owners are required to have a maintenance system in place that defines how and when their equipment and systems will undergo survey. Several classification-approved survey systems exist to help vessel owners meet these requirements, providing a range of options for inspection scope and timing, and equipment monitoring.

Three class-approved survey systems

Several survey systems are recognized by IACS classification societies as suitable frameworks for performing machinery maintenance.

  • Normal Survey System: All machinery items are surveyed by the classification surveyor once every five years during the ship’s renewal survey.
  • Continuous Survey System: All machinery items are inspected every five years, with the survey delegated to the chief engineer before the confirmatory survey is performed by a classification surveyor.
  • Planned Maintenance Survey System (PMS): Each machinery item has its own customized maintenance system. These equipment systems can include Condition Based Maintenance (CBM), where maintenance is determined through condition monitoring by performing diagnosis and prognosis on the machinery item’s actual condition. Predictive Maintenance offers an optimized version of CBM, where the diagnosis and prognosis are based on complex algorithms instead of thresholds or standards.

Most ship owners today choose either a Normal Survey System or a Continuous Survey System, enabling them to meet regulatory requirements. However, as greater digitalization and improved monitoring technology have become available, owners can move to upgraded systems that further optimize maintenance planning, reliability and costs.

Upgrading to a Planned Maintenance Survey System

Transitioning to a PMS enables vessel owners to uniquely tailor and optimize maintenance to their ships’ specific needs. By integrating a PMS onboard, each machinery item is given an individual maintenance schedule and scope. This could be determined based on manufacturer recommendations, running hours or running cycles. Rather than undergoing a complete survey every five years, owners can take a targeted approach to maintaining equipment, inspecting machinery based on actual use. The PMS is supported by the implementation of a Computer Machinery Maintenance System (CMMS), where the chief engineers can initiate the PMS and manage the maintenance tasks for each equipment piece via a software solution onboard the ship.

A digital tool for changing maintenance systems

For owners who choose a PMS system, Bureau Veritas is developing an online platform that connects directly to owners’ CMMS. From planning initialization to in-service operations, the platform will collect data on the maintenance status of all machinery items, manage modifications to onboard equipment, and offer access to manufacturer manuals. This will enable ship managers and BV surveyors to get a clear, comprehensive overview of onboard machinery maintenance, efficiently prepare for surveys, and assess the machinery maintenance conditions.

The future of Condition Based and Predictive Maintenance

PMS is a key stepping stone for developing a CBM approach that is supported by a Condition Monitoring System onboard that collects condition data from machinery and generates a precise diagnosis and prognosis. The Condition Monitoring System can be a combination of fixed sensors and condition data treatment, measurements from portable devices or sample analysis. Ship owners gain a perfectly up-to-date view of their equipment, with the ability to detect when a failure is about to occur and to predict when equipment will fail. With a CBM approach, owners can improve maintenance planning and efficiency, gaining an exact understanding of which systems need maintenance and when.

Looking further ahead, the marine industry will use PMS and CBM as a basis for developing Predictive Maintenance. Simple CBM means that diagnosis and prognosis are based on preset threshold values of the condition measurements. These are determined by manufacturer recommendations or international standards. This differs from predictive maintenance, where diagnosis and prognosis are based on actual and historical condition data analyses. These data analytics use complex algorithms that can be driven by artificial intelligence and machine learning. Predictive Maintenance accounts for all machinery information, both past and present, in order to optimize future maintenance.

Dung Huynh Duc
Dung Huynh

Fleet Management Director

Bureau Veritas Marine & Offshore

Classification societies have a crucial role to play in helping ship owners transition to more optimized machinery maintenance systems. By ensuring that CMMS and condition monitoring systems are properly designed, installed and operated onboard, we can improve maintenance throughout a ship’s lifecycle, saving owners time and reducing long-term costs.

Supporting adoption of your machinery maintenance plan

Bureau Veritas supports ship owners and managers in their choice and implementation of machinery maintenance systems, helping owners manage high-level classification requirements. We consider three systems based on our Rules and developed in accordance with the standards accepted by flag administrations.

Our Normal Survey System ensures that a qualified Bureau Veritas surveyor inspects all machinery during five-year renewal surveys. For a Continuous Survey System, Bureau Veritas conducts the confirmatory survey following the chief engineer’s inspection. These two systems form a regulatory baseline for ship owners, enabling them to comply with existing ISM Code requirements.

For vessel owners looking to integrate more optimized and complex systems and regular data collection into their maintenance planning, we approve the ship owners’ CMMS and conduct initial survey of the PMS. We then conduct periodic audits of the PMS, including CMMS records. Ship owners can also integrate CBM into their PMS, undertaking plan approval of the condition monitoring system before asking for an installation survey by our surveyor.

Finally, Bureau Veritas’ technical and digital experts are currently laying the groundwork for a Predictive Maintenance plan. This will be a key focus through 2025, as we help bring ship owners into the next era of marine digitalization.