Is the ship design spiral holding you back?

By Elspeth Mosedale

Ask any naval architect how to design a ship and they will generally draw the same diagram: a spiral. The ship design spiral has been the standard way of working for decades. But what does it really show us about ship design, and is there a better way to approach this complex process?

What is the ship design spiral?   

The design spiral is a representation of the stages of ship design. There are four phases: concept, preliminary, contract and detail. Each phase runs through the same set of requirements in turn, including proportions and powering, arrangements, capacities, stability and ultimately cost estimates. The design must ‘tick the box’ for each requirement. Once the design meets the first, concept phase, it moves on to the more detailed preliminary design. The spiral repeats again for each phase in turn.

Marine design spiral
The design spiral shows the many stages required in ship design

This design spiral was originally developed in 1959. And this same representation is still valid today, over sixty years later! While this spiral looks logical, it is not that efficient. Over time, ship design has become more complex, with more requirements to meet, more systems to optimize and more analyses to perform. The problem with it is the sheer number of stages it contains within each phase. Any change to the design must be run through all stages in turn again. This takes time, and can mean that detailed analysis is not run on all designs.

As well as this, while the spiral looks like a smooth, continuous process, it is actually made up of separate items. Each of these involves a different team, focused on one aspect of ship design and performance. Teams generally use different tools, and different data sets. The spiral does not show the bottlenecks and silos that can happen when passing information between teams.

Is there a better way?

As we have discussed before, ship yards and designers are under increasing pressure to create efficient designs in shorter time frames. Failure to meet the required targets leads to financial penalties. And the current economic climate means that only the best ship yards can survive: financial penalties must be avoided.  The inefficiencies in the existing ship design process are now causing problems, rather than helping to provide results. Is it time for a change? What if we could enable faster design and collaboration across teams? What would the result be in terms of innovation in design?

In our latest white paper, we argue that the time has come to move away from the design spiral, and instead use a new approach, based on the digital data handling and simulation tools available today. The paper describes an integrated design process, where CAE simulation is linked directly to CAD models, performance data and design optimization tools. With this approach, naval architects can analyze multiple performance requirements at the same time. Ship yards could investigate hundreds of options via simulation, and rapidly focus in to specific design variants which meet the mission requirements.

Simulation-driven ship dsign example
Automated design analysis links parametric CAD models with CAE simulation. This enables rapid analysis of multiple hull variations, with feedback between simulations and CAD.

The benefits of a new approach

Simulation-driven design makes full use of integrated design tools, automated workflows and intelligent design exploration. The paper details the stages within the process and shows the benefits of working this way. These include:

  • A speed-up in simulations, so you can analyze more designs in the allotted time
  • Greater insight into the factors affecting vessel performance
  • Naval architects can focus on analysis of results, rather than setting up software.

The integrated nature of this process can also provide significant cost savings, by reducing overall design times and bottlenecks in data transfer or design analysis. Naval architects can evaluate many more design variants. This means that they can move beyond standard designs, and focus on improvements and innovations.

Dejan Radosavljevic, author of the white paper, comments that:

“For shipyards to survive and even thrive in these difficult economic times, they need to think innovatively, think holistically and be agile. Simulation-driven ship design fits all three of these needs”.

This article first appeared on the Siemens Digital Industries Software blog at