Elastic Shaft Alignment

The Elastic Shaft Alignment (ESA) Notation is mandatory for many categories of large ships, depending on propulsion power capacity. To ensure that they are compliant, and that their vessels are running at optimal efficiency, ship owners must therefore assess the alignment of their vessels’ shaft line and bearings.

BV Solutions M&O supports ship owners with ESA reporting and analysis, using time-proven, robust, in-house software such as LILAS. Our comprehensive ESA solution helps shipowners optimize vertical bearing positioning, thereby avoiding costly drydocking required for repairs when bearings fail.

Our added-value

LILAS is our industry-leading software and one of the longest-running systems on the market for ESA studies and classification

To correctly install bearings, we provide a comprehensive solution, working with shipyards to help them analyze Gap and Sag and Jack-up tests following an ESA study

Our ESA expertise is bolstered by our longtime experience and worldwide network—especially with Korean and Chinese shipyards, where large LNG and container ships are built

ESA services with LILAS

Our LILAS software models the shaft line, providing the optimal vertical position for the bearings, thus helping prevent abnormal wear and tear or outright bearing failure. This ensures durability over the lifetime of the vessel. The optimal vertical positioning derived from an ESA study enables owners of container ships, LNG carriers and oil tankers to avoid extremely costly bearing repairs down the line.

Better designs powered by modeFRONTIER

Our ESA study methodology employs modeFRONTIER design optimization software to ensure that we deliver the very best design solution to the shipyard. The modeFRONTIER software reduces complexity, improves efficiency, and cuts down on development time.

Covering static and in-service conditions

Our ESA experts check both the vessel’s static conditions and its running conditions. When evaluating running conditions, we do so at lowest to highest speeds. In this way, we can ensure that the vessel is safe in all operational modes. The global ESA solution goes beyond bearings assessment to analyze computational fluid dynamics (CFD) for the vessel’s propeller loads. These computations are known for higher accuracy results than those derived from empirical formulations.

All-inclusive with Gap and Sag and Jack-up test method

Once we establish the optimal vertical positioning for bearings, we provide further operations computations to help ensure that shipyards install the shaft line and bearings correctly. The first computation is Gap and Sag, the procedure of verifying the alignment condition prior to shafting assembly. Next, we apply the Jack-up test method to gauge the reaction of a bearing in correlation with the jack load to validate the vertical position of the bearings.

Doriane Causeur

Head of Propulsion Team

BV Solutions M&O

While ESA notation is a requirement for many large vessels, it is also a true cost-saver for shipowners. By ensuring that a vessel’s shaft line and bearings are optimally positioned, shipowners increase a vessel’s lifetime and save money by avoiding costly repairs.