“We are very pleased that we were able to use our innovative design and aluminium shipbuilding knowledge to support what will be among the most environmentally friendly coastal cruise ships in service,” says Chris Moyle, Sales Director Marine & Offshore in Hydro’s Extruded Solutions business.

The two Norwegian coastal cruise ships (Kystruten) ships ‘Havila Capella’, ‘Havila Castor’, will be identical: 124.1 meters long, 22 meters wide and able to carry 640 passengers. The ships will be powered by LNG (liquefied natural gas) and batteries. The ships will be delivered to the customer at the end of 2020.

Hydro was awarded the contract by Tersan Shipyard in Turkey after reviewing light-weight alternatives to steel for the upper sections of the ships. The advantage of aluminium is the possibility to design extrusions with a very high strength-to-weight ratio compared to steel. By choosing aluminium extrusions from Hydro, it was possible to reduce the overall weight of the vessels to improve displacement and draught issues. When using aluminium instead of steel, the overall weight reduction of the selected area was about 50%.

“We are pleased to be working with Hydro for the supply of their innovative aluminium products. Their know-how brought additional value to the projects while reducing the weight. We trust we will have opportunities to establish a good long-term cooperation,” says Turgut Özden, Deputy Shipyard Director of Tersan in Yalova.

Hydro delivered an optimized aluminium design to meet the following criteria:

• Space restrictions such as ceiling heights and pillar locations
• Reduce the weight as much as possible
• Provide an innovative design to speed up the construction process
• Meet all the strength and deflection requirements

The concept design from Hydro was incorporated into the Havyard design and approved by DNV-GL. When the concept from DNV-GL was approved, Hydro started working with Tersan to fine tune the profiles and Friction Stir Welded (FSW) panel designs.

Industry trend

The coastal cruise ships from Havila Kystruten AS are equipped to the highest technological and environmental standards with the objective to travel silently and emission free.

“There is definitely a trend in the ship building industry now with ship builders and designers looking for light-weight alternatives. A key reason is due to shipping regulations related to environmental requirements,” says Moyle.

Hydro has already established a solid presence in a large part of the maritime industry, supplying thousands of tonnes each year to cruise ships, ferries, yachts and for various other vessel types.