Stena Weco Impulse delivered from shipyard in China

By Vessels

The chemical and product tanker Stena Weco Impulse, which is jointly owned on a 50-50 basis by Stena Bulk and the Danish Weco Group, has now been delivered from the Chinese shipyard CSSC Offshore & Marine Engineering (CSSC OME) in Guangzhou. The Stena Weco Impulse, an IMOIIMAX tanker, is the sixth in a series of 13 vessels ordered by Stena Bulk. She is now en route to several Indonesian ports where she will load vegetable oils after which she will sail to Barcelona and Rotterdam to discharge her cargo. The naming ceremony will take place in Copenhagen in June 2016.

All the thirteen IMOIIMAX tankers will sail in Stena Weco’s global logistics system, which currently employs more than 60 vessels.
Stena Weco Impulse is equipped with 18 tanks, each with a capacity of 3,000 m3, and can carry both vegetable oils and chemicals such as oil and petroleum products. Thanks to their innovative technical design, the IMOIIMAX tankers have extra large cargo flexibility, high safety and low fuel consumption. The IMOIIMAX tanker is equivalent in size to a 50,000 dwt MR tanker.

Stena Weco Impulse delivered from shipyard in China

“We are very pleased with this addition to our IMOIIMAX fleet. The Stena Weco Impulse is the first of two vessels, which we will jointly own with the Weco Group, and this will strengthen still further our very successful collaboration”, says Erik Hånell, President and CEO Stena Bulk AB / CEO Stena Weco.

“Together with Stena Bulk, we have built up a fleet of more than 60 vessels, all of which sail in our advanced logistic system. The fact that we are now focusing on joint ownership is yet another step towards more far-reaching collaboration”, says Johan Wedell Wedellsborg, Chairman of the Board, Weco Group.

“The IMOIIMAX model fits in very well with how we operate due to its extra large cargo flexibility. We are convinced that the vessels will play an important role in our joint fleet”, adds Johnny Schmølker, CEO Weco Shipping / COO Stena Weco.

The first five IMOIIMAX tankers have been delivered by January this year. Delivery of the remaining eight vessels will be completed by the end of 2017. Additionally, there is an option on a further two vessels.

Stena Teknik and the shipyard CSSC OME were jointly responsible for the technical development of the IMOIIMAX concept. The innovative design of the IMOIIMAX tankers means that, among other things, their fuel consumption at service speed is 10-20% lower than that of equivalent vessels.


Some of the technical solutions that result in more efficient energy consumption and greater logistic flexibility:

  • Main engine auto-tuning

With an auto-tuning system, the combustion process in each cylinder is continuously and automatically controlled for optimal main engine performance.

  • More efficient boiler with recovery from multiple heat sources

The vessel is also equipped with a so-called exhaust gas multi-inlet composite boiler, one of the very first to be installed. This boiler not only recovers energy from the main engine’s exhaust gas but also recovers the exhaust gas energy from the auxiliary engines.
In addition the boiler has an oil-fired section that can be used in port, thus avoiding the need to run the larger oil-fired boilers to heat the vessel. This, together with main engine auto-tuning and part-load optimization of the auxiliary engines, will result in very efficient energy consumption.

  • Recovery of propeller energy loss

All propellers lose some of the energy input in the rotating water behind the propeller. With the IMOIIMAX, the energy loss is recovered by fitting a Hub Vortex Absorbing Fin.

  • Aerodynamic design of the accommodation and bridge

In heavy weather, wind resistance can be significant. The streamlined design of the accommodation and the bridge means that the IMOIIMAX is less affected by wind resistance than other similar vessels.

  • All cargo tanks are designed to accept any type of cargo the vessel can transport

An IMOIIMAX has 18 cargo tanks. They are all the same and are designed to hold a maximum of 3,000 m3, i.e. the maximum volume permitted for the special-type cargoes the ship can transport.

  • Effective tank-cleansing system

The flushing system installed ensures that the cleansing process is optimised and since four tanks at a time can be flushed, the time between discharge and loading can be minimized.

Technical data for an IMOIIMAX tanker: Length: 183 metres; beam: 32 metres; deadweight: 50,000 tons

Source: Stena Bulk