Condition Assessment Programme: building trust between owners and charterers

 

A valuable fleet evaluation

Conducting a 2D structural CAP provides reassurance when chartering or operating a fleet. The study assesses the vessel's structural integrity of the vessel's cargo hold, providing information about its actual hull girder capacity combined with corrosion data from ultrasonic thickness measurements (UTM). It also identifies the fatigue hotspots and the appropriate monitoring procedures to anticipate future issues. This enables asset owners to provide a “roadmap” to surveyors, indicating points of attention and potential causes for concern.

As European nations look increasingly to marine carriers to source their oil and gas needs, assets are being directed toward new missions. These vessels will need to fulfill a different set of specifications and operate in new conditions. For these vessels, our CAP service will be a relevant throughout and beyond the asset’s design life. They will confirm that there has been no detrimental impact from conversion and corrosion on the vessel’s integrity, which could challenge the operating envelope.

What’s more, the lifespan of vessels has increased in recent years. Owners are looking into life extension, and the CAP outcomes are an essential input in the vessel’s later life. Ultimately, asset owners need all the information on their vessels or units to satisfy charterer’s needs and instill confidence in the future operation of their fleet.

The calculations behind CAP

The CAP may involve a full assessment of the vessel, including its machinery, equipment and structure. It analyzes the strength and fatigue of the asset by using either 2D structural studies only, or complemented by 3D analyses. The analysis of the structure’s strength is to ensure the vessel will be able to handle the loads it will be subjected to during its operation. 

To be as realistic as possible, structural calculations are performed in close partnership with surveyors. Depending on the timeframe, these calculations may take into account previous UTMs to guide the charterer and BVS surveyors in their inspection. They may also factor in UTMs made more recently to help quantify the structural impact of corrosion.  

CAP providers should be conservative in their estimations, prioritizing maximum design loads over rule loads. For fatigue assessment, providers need to base calculations on an environment as close as possible to reality. Clients give their input about the asset’s operating conditions and future wave distribution. Taking these factors into account, the potential fatigue of the structure can be estimated. 

The aim of the CAP is not to ensure vessels meet requirements, but rather to assess their current condition and highlight any potentially critical areas. Owners can then best adapt their maintenance systems to the state of their fleet.

Three factors to assess. 

When conducting CAPs for life extension studies, fatigue analyses must consider three different phases:

• Past life Calculations take into account the vessel’s previous functions, operating conditions and their potential impact on the vessel
• Transit phase If the vessel is in transit to its new operating location, the effects are considered in the CAP
• Onsite operation CAP providers will assess the conditions in which the asset will be operating, and how will it behave depending on its current condition

Providing an accurate assessment

To successfully carry out a CAP, it is important to collect all the necessary input data and documentation from the asset’s owner. In cases where structural strength and fatigue analyses are used for life extension studies, this data includes as much routing data and operating history as possible. Without this information, providers can only make conservative estimations for the fatigue life. Note that for converted vessels, this is also applicable for both past life and – if relevant – transit phase.

Furthermore, when conducting a CAP, there may be a difference between rule design loads and actual vessel design loads – typically from the trim and stability booklet. In this instance, it is a best practice to align as far as possible with the real load to provide more accurate results about the vessel’s integrity.

BV Solutions M&O : experts in CAP

BV Solutions M&O relies on its existing advanced CAP methodology to provide best-in-class service. In 2021, BV Solutions M&O carried out over 100 CAP projects. in Nantes, our team of experts handling the structural calculations as part of the CAP has extensive experience in structural fatigue analyses.

As part of a renowned global group, we perform CAPs according to the most stringent rules, guaranteeing the study’s acceptance. We remain independent from the owner to provide an objective assessment of a fleet. Furthermore, our teams can provide complementary services to broaden the CAP findings. Based on additional analyses, we offer advice and solutions to overcome owners’ and charterers’ concerns. Tailoring our services to your needs, our assessments can extend from 2D strength and fatigue analysis to 3D studies, heading analysis and hydrodynamic analyses.

Our team of experts is equipped to handle very large fleets. We are currently working with Nakilat to carry out CAP analyses on 21 ships in its LNG carrier fleet. The vessels are all close to 15 years old, and the CAPs will be scheduled during Nakilat's routine dry-docking processes in Qatar. Nakilat and our other clients put their trust in us to provide in-depth analysis and an impartial assessment of their fleet's condition.