How to produce ship hulls at a lower cost?

In the late 1990s, shipyards in Northern Netherlands were well known as the most efficient builders of short-sea vessels in the world. Fast-forward 20 years and the situation has changed; shipyards with lower wages in other parts of the world can produce short-sea ship hulls at lower cost.

A group of companies, shipyards and other stakeholders in Northern Netherlands have taken up the challenge of restoring the competitive advantage of the region.

Conoship and Cadmatic have been key participants in driving this process. Guus van der Bles, Director Development at Conoship International BV and Cadmatic Technical Director Paul Filius have known each other and worked together in shipbuilding development since the late 1980s.

When they discuss ways of improving shipbuilding, they say that many of the ideas being implemented today were around already in the 1990s. The difference is the ideas can now be implemented thanks to digitalization and modern design and information management tools.

Guus van der Bles (left) and Paul Filius have been tackling shipbuilding development questions since the late 1980s.

Challenge to reduce kilogram cost of steel hull by 30%

With help of local and EU funding, Guus and Paul have been involved in several projects to improve ship production in Northern Netherlands.

The first of these projects aimed to identify whether shipyards in Northern Netherlands could reduce the kilogram cost of a completed hull (Casco) from € 3,5/kg to €2,5/kg, and if so, where these cost reductions could be achieved.

“The study was performed by Conoship in cooperation with Cadmatic and about 10 shipyards. It looked at the whole value chain from design, engineering, material selection, prefabrication, section building, section block assembling to pre-outfitting of the hull,” says Guus.

“Optimizing design and engineering for cost-efficient production is very important and accounts for 33% of the cost reduction required. It requires modern tools such as Cadmatic and using the 3D model for much more than just the generation of construction drawings.”

“Clever optimization of the constructional design of ship hulls is required, focusing on the reduction of material costs and production manhours.”

“This should be followed by very clever selection of construction details, related to the most cost-effective assembly and welding methods. We think that this could partly be automated in CADMATIC Hull,” Guus explains.

Another core pillar of the proposed cost reduction can be achieved via robotization. Guus explains that this refers both to the centralized preproduction of micropanels in a robotized panel line (supplying a cluster of shipyards), as well as increased robotization and digitalization at shipyards themselves.

“Instead of shipping, for example, 500-800 lose parts for 1 block-section from a steel-parts-prefabrication factory to a shipyard, a central robotized factory can pre-assemble those parts to about 50 micropanels or sub-constructions of maximum 12m x 3m x3m that are robot-welded, grinded, and painted.”

“The finished and coated subconstructions can then be transported by truck and trailer to the shipyards for block assembly,” says Guus.

This shared, robotized panel line contributes about 14% to the needed cost reduction. Together with robotization and digitalization at the shipyards themselves, the total reduction can be extended to approximately 33% percent.mir

The remaining 33% of the cost reduction comes from optimizing logistical planning & control, based on the logistical work breakdown structure.

It requires wider use of the 3D model beyond steel parts to include piping, installations, and equipment to increase the logistical control and planning of the complete shipbuilding and outfitting process.

“Shipyards recognize that they can improve their productivity by being more efficient in controlling logistics.

An information management tool like CADMATIC eShare can play a much bigger role here, for example, to select steel construction parts, outfitting parts, systems, and other items from the 3D model with properties that enable you to generate production planning items and to control manhours, progress, and the logistics of the shipbuilding-, installation- and outfitting processes. It helps you to check whether the actual situation corresponds to what was planned.”

Several ongoing projects

The initial research report of 2019 has led to several ongoing projects that are delving into the details of achieving the cost reductions in different phases of the shipbuilding process.

For instance, in design and engineering, an engineering manual has been created for shipyards on how to do the most cost-effective engineering and work has been started in integrating this into Cadmatic.

Guus says profile cutouts is a good example of a construction detail where a clever selection during the engineering-phase can help to reduce cost in production.

“Cadmatic provides several different kinds of cutouts, but we have defined one or two that are optimal in terms of achieving our desired cost savings, tuned to the most efficient assembly- and welding methods, also considering robotized welding.”

Paul says that it goes deeper than the contour of the cutout.

“You must consider what effect the cutout has on welding, assembly, and profiles near to the cutout itself; it affects the whole chain. When you identify an area of improvement which is replicated thousands of times in a shipbuilding project, you start seeing very significant efficiency improvements.”

“Once we have this level of detailed requirements and information from the shipyards, we can come up with solutions,” says Paul.

Both Guus and Paul agree that a lot of work lies ahead, but that the coming together of minds and purposeful working together to achieve a joint goal in Northern Netherlands is bearing fruit.