Ideally, the data recording method used should be uniform
so that information can be easily collated and analysed to facilitate
the extraction of the required information. The collection of data
from ships should include the distance travelled, the quantity and
type of fuel used, and all fuel information that may affect the amount
of carbon dioxide emitted. For example, fuel information is provided
on the bunker delivery notes that are required under regulation 18 of MARPOL Annex VI.
If the example formula given in the Appendix is used, then the
unit used for distance travelled and quantity of fuel should be expressed
in nautical miles and metric tonnes. The work done can be expressed
using units appropriate for the ship type in paragraph 3.5.
It
is important that sufficient information is collected on the ship
with regard to fuel type and quantity, distance travelled and cargo
type so that a realistic assessment can be generated.
The
distance travelled should be calculated by actual distance travelled,
as contained in the ship’s log-book.
Amount and
type of fuel used (bunker delivery notes) and distance travelled (according
to the ship’s log-book) could be documented by the ship based
either on the example described in the Appendix or on an equivalent
company procedure.