Efficient ship additional class notation

Energy Efficiency Design Index additional class notation

RINA has designed the additional class notation EFFICIENT SHIP - EEDI (Energy Efficiency Design Index), to identify ships having good energy efficiency performance under a specified operational speed and DWT (Dead Weight Tonnage).The additional class notation is assigned to ships for which hull, propulsion and electrical power generation efficiency, at specific speed and draft, is verified by a third part society and found beyond the minimum efficiency values established.Being EEDI a design index, it is not capable to catch the efficiency of the ship in the real operative pattern.

Technical focus

Nowadays the cost of fuel is a very sensitive subject for the marine industry. Fuel saving design and fuel saving techniques are advertised, analysed, implemented and evaluated by ship-owners and stakeholders, and are an instrument to highlight technically sound solutions as needed.
The additional class notation EFFICIENT SHIP highlights that a ship has:

  • main and auxiliary engine characterized by high efficiency
  • a low fuel oil consumptions, that does not preclude the ship from having a good working capability.


The process for the assignment of the additional class notation is:

  • examination of required documents
  • performance outcome of dedicated sea trials.


New building specifications are reporting daily fuel oil consumption decreasing in these last years: a third party evaluation of the real operative ship efficiency is more and more important.
RINA is among the first classification societies to issue an additional class notation, dedicated to energy efficiency of a ship and based on the verification of the ship’s engine efficiency and of the ship’s transport capability at a specified speed and draft.


Is the additional class notation specific for ship type?
Yes, EFFICIENT SHIP contains different parameters for ship type and for two and four strokes engines.

Is it possible to assign EFFICIENT SHIP to all ships?
Yes, this additional class may be granted to new buildings and ships already classified by RINA or not.

Andrea Cogliolo Director Marine Business Line

+39 010 5385259
+39 335 1882632

You may also like