Foreword
In order to comply with the new sulphur limit for fuel oil used on board ships taking
effect from 1 January 2020, residual fuel oils with sulphur contents of 0.50% or lower
(hereafter, referred to as "compliant fuel oils" in this booklet) will be distributed globally
and loaded on board ships. Consequently, the number of occasions where fuels for main
engines or auxiliary engines are changed from conventional fuel oils to compliant fuel
oils and actually used will increase.
ClassNK, having summarized the potential risks related to the changing over from
conventional fuel oils to compliant fuel oils and the measures necessary to mitigate said
risks, has decided to make this information available to the ship crew members who are
actually responsible for such operations.
The purpose of this booklet is, therefore, to provide ship crew members on board going
to bunker and actually use compliant fuel oils with information focusing on the
"compatibility" and "cold flow properties" of such fuels as well as the risks associated
with such fuels and the measures to be taken to mitigate such risks.
In addition, at our request, relevant recommendations and product leaflets for
mitigating the potential risks of compliant fuel oils have been provided by several
chemical makers pertaining to the sludge dispersants and sludge solubilizers that are
referred to in this booklet. These materials are added as attachments to this booklet.
In cases where HSFO (High Sulphur Fuel Oil) has been stored in a ship’s fuel oil
storage tank before compliant fuel oil is loaded in the tank, on the other hand, sludge
may precipitate on the bottom part of the tank or on the tank walls. In such cases, if a
compliant fuel oil was loaded into the tank without due considerations, then it might
lead to operational problems in the fuel oil purifiers, filters and engines, or sulphur
content of the mixed fuel oil in the tank might exceed 0.50%.
In this regard, the development of a plan to manage fuel oils within a sulphur content
of 0.50% or lower, including the preparation for fuel oil change-over by tank cleaning, is
recommended; for example, the Ship Implementation Plan referred to in the IMO’s
Guidance on the development of a ship implementation plan for the consistent
implementation of the 0.50% sulphur limit under MARPOL Annex VI
(MEPC.1/Circ.878).
When developing a Ship Implementation Plan, please refer to the sample plan that
ClassNK has provided
.
Please refer to ClassNK Technical Information TEC-1179 for more information.