The chemical and product tanker Stena Imperative has been delivered from the Chinese shipyard CSSC Offshore & Marine Engineering in Guangzhou. The IMOIIMAX tanker is equivalent in size to a 50,000 dwt MR tanker. The vessel 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 IMOOIIMAX tankers have extra large cargo flexibility, high safety and low fuel consumption. The naming ceremony will be held in Hong Kong on 26 January 2016.

Stena Bulk takes delivery of IMOIIMAX tanker Stena Imperative

Image: Stena Bulk

Stena Imperative, which is wholly owned by Stena Bulk, is the fifth in a series of ten tankers ordered by Stena Bulk in 2012. The first four vessels were delivered in 2015 and the remaining five will be delivered by 2017.

“From the beginning, we had great expectations when it came to function and results since IMOIIMAX is a further development of an established and successful concept. Now, after a year in operation, it is clear that the vessels have met all our expectations in terms of both technical and commercial performance”, says a satisfied Erik Hånell, CEO of Stena Bulk.

In November last year, Stena Bulk placed a further order for the same vessel type, this time for three tankers with an option on a further two. Delivery of the first of these is planned for the end of 2017.

All the IMOIIMAX tankers will sail in Stena Weco’s global logistics system, which currently employs about 60 vessels.


Image: Kan Tam

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 will 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