Rudder & aft ship design optimization using CFD

A well optimized aft ship and rudder design can have a significant impact on vessel performance. Using Computational Fluid Dynamics (CFD), Marimecs analyses the interaction between the hull, propeller and rudder to identify opportunities to improve efficiency, steering behaviour and hydrodynamic performance.

This approach can be applied to both new designs and existing vessels where modifications can reduce resistance, cavitation and fuel consumption.

Improving performance below the waterline

The flow around the aft ship is influenced by the hull shape, propeller and rudder. These components interact continuously and therefore cannot always be optimized individually.

An inefficient configuration can result in increased resistance, cavitation, vibration, poor steering behaviour or unnecessary energy losses.

Marimecs uses CFD simulations to gain insight into these interactions. By visualising flow patterns, pressure distribution and hydrodynamic forces, we can identify where improvements can be made.

Rudder optimization

A rudder does more than control the direction of a vessel. Its profile, position and interaction with the propeller flow can also influence resistance and propulsion efficiency.

Using CFD, different rudder configurations can be analysed and compared before modifications are made. Depending on the vessel and the results of the analysis, optimization can include changes to the rudder profile, geometry, position or alignment with the propeller flow.

The objective is a rudder design that works effectively within the complete aft ship configuration.

Aft ship optimization

The performance of the rudder is closely connected to the design of the aft ship.

For this reason, Marimecs can extend the analysis beyond the rudder itself and investigate the complete flow around the stern.

Hull geometry, appendages, the propeller arrangement and the transition towards the rudder can all be included in the CFD model. This makes it possible to identify hydrodynamic losses and evaluate different design modifications.

Optimization of existing vessels

CFD based optimization is not limited to newbuild projects. Existing vessels can also benefit from an analysis of their current aft ship and rudder configuration.

Operational issues such as high fuel consumption, cavitation, vibration, limited speed or unstable steering can provide a reason to investigate the hydrodynamic performance of the vessel. Existing drawings, vessel data and operational measurements can be combined with CFD analysis to determine possible causes and develop practical modifications.

This allows improvements to be considered without redesigning the complete vessel.

From CFD analysis to engineering

The process does not stop with the CFD results. Once an improved configuration has been identified, Marimecs can translate the proposed modifications into the engineering required for production and installation.
This combination of CFD, naval architecture and engineering makes it possible to take an optimization from initial analysis through to a practical modification of the vessel.
Rudder and aft ship optimization can contribute to:

Reduced resistance

Lower fuel consumption

Improved propulsion efficiency

Reduced cavitation

Improved steering behaviour

Reduced vibration

Improved vessel performance

Better interaction between hull, propeller and rudder

Possible design modifications

Based on the CFD analysis, different modifications to the rudder and aft ship configuration can be evaluated.
The optimal solution depends on the vessel, propeller arrangement and operational profile. Possible modifications include:

Asymmetrical rudder design

The leading edge of the rudder can be adapted to better align with the direction of the propeller wash. An asymmetrical design can reduce crossflow forces on the rudder and improve the interaction between the propeller and rudder.

Optimized rudder profile

The shape and thickness distribution of the rudder can be optimized based on the local flow conditions. Adjusting the profile can improve water flow around the rudder, reduce turbulence and contribute to better hydrodynamic performance.

Propeller hub extension and rudder bulb

A propeller hub extension combined with a rudder bulb can improve the flow between the propeller hub and rudder. This can reduce turbulence and transverse forces while improving the overall interaction between the propeller and rudder.

Ready to optimize your fleet?

If you’re seeking a partner who combines simulation tools with deep hydrodynamic expertise, contact Marimecs. Let’s explore how we can elevate your vessel’s performance through innovative design and optimization.

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Marimecs is part of the Marimecs Group, which consists of independent brands, each operating in its own field for shipyards, owners and suppliers.