FLEXI – Sirius builds an LNG-tanker

The newbuild Coralius is designed to fulfill the requirements of a fully IGC-classified vessel, while also taking into account anticipated future standards and charterers’ requirements.


The vessel is designed for both efficient short sea trading and STS LNG bunkering operations for all types of vessels, both inshore and offshore. Thus the project name “FLEXI” for flexibility.

Coralius will be built at the Dutch Royal Bodewes shipyard by the joint venture “Sirius Veder Gas AB”. The hull will be built in Poland. Fitting-out will be done by Royal Bodewes. The bilobe tanks will be manufactured by TGE.

Coralius is constructed to meet the every need of customer SkanGas, who will take delivery of the Coralius on a long time-charter.

Coralius is being built in the joint industry project (JIP) Flexi as one of the activities in the Pilot LNG umbrella project. The activity is co-funded by the EU under TEN-T and part of the Zero Vision Tool platform. The aim of the activity is to develop the LNG bunkering infrastructure by offering an LNG bunkering facility in the Skagerrak/Kattegat area in cooperation with the Skangas Brofjorden Terminal. The development of a fast, efficient and safe bunkering system and procedures for LNG bunkering inshore and offshore is also part of the activity. Follow this link to watch a video about the project.

Cargo system

The cargo system is based on two LNG tanks of bilobe type designed for 4.5 bar(g) with a total volume of 5800 m3, two compressors and four cargo pumps. The capacity of the cargo pumps will be 4 × 250 m3/h and the cargo compressors will have a capacity of 2 × 532 m3/h. The loading/discharge capacity will be abt 1000 m3/h. A redundant nitrogen generator configuration will be installed. Cargo operations will be achieved without any release of methane, since the boiler burns a suitable mixture of methane and nitrogen. With this boiler, methane slip is zero, which is an important factor in the vessel’s environmental performance.

The manifolds will be located at two positions along the vessel in order to achieve the best flexibility for receiving vessels or terminals.

The cargo automation system is supplied by Siemens Automation.

"5800 m3 in 2 independent cargo tanks, which act like 4"

Anders Bejre, Project manager


The bilobe tanks are separated by a bulkhead, which creates 4 independent cargo tanks, while still communicating on the “gas side”. Illustration: FKAB

Nominated to Nor Shipping Next Generation Ship Award 2015, the top four candidates


The Next Generation Ship Award was conferred on the ship project demonstrating the greatest advances and innovation in design. The design was assessed with respect to energy efficiency, innovation, suitability and flexibility, technology utilization, safety and security and environmental sustainability. All ship types were given equal consideration, regardless of size or segment.

Since innovative efficient designs often emerge through active collaboration between companies, partners may apply jointly. Eligible projects are those that are contracted but not delivered, or are likely to be contracted and built within the next 10 years.


This 5,800 m3 vessel will feature a dual-fuel engine, thrusters that facilitate enhanced close-quarters manoeuvring and ice class notation (1A), which will allow it to trade in the Baltic region during winter. In combination with the low block coefficient hull form, emissions will be significantly lower than those of conventional vessels, as the ship will run on LNG from the cargo. The building of Coralius is part of the EU Pilot LNG project, which aims to establish an LNG bunkering infrastructure. Coralius will be owned by Sirius Veder Gas AB, a joint venture between Sirius Rederi and Anthony Veder.

"We are proud of this new design, which reflects both our local knowledge and our extensive experience."

Jonas Backman, MD

According to the above, all modes can be performed using LNG as fuel. In combination with the very low block coefficient hull form, emissions will be extremely low compared to conventional vessels. Coralius will be equipped with one bow thruster of combination type, also suitable as alternative propulsion, and one stern thruster. All will have high redundancy and reliability.

Other specifications

Cooling water waste heat from all installed engines will be transferred to the vessel’s heat consumers, to further reduce emissions. Biodegradable oil will be used for the stern tube arrangement. Comfort class will be used to provide high standards for the crew onboard. The company’s philosophy recognizes that a high crew retention rate is important for building up the best knowledge and experience onboard and achieving the absolute best vessel performance.

The fender arrangements were developed so that no heavy lifting is required; two cranes on deck and fender-cradle arrangements facilitate bunkering equipment handling.