Third IMO Greenhouse Gas Study 2014

Annex 7 261
Oil tankers
The average productivity of oil tankers has varied greatly in the last four decades (see Figure 38) with a
maximum of 90,000 tonne-miles per dwt in the early seventies and a much lower peak at the beginning of
the twentieth century (34,000 tonne-miles per dwt), and a minimum in the early eighties (18,000 tonne-miles
per dwt). The fluctuation has therefore been stronger than for the world fleet as a whole.
Figure 38: Productivity of oil tankers measured in thousand tonne-miles per dwt, 1970–2013
In 2012, we found the productivity of oil tankers to amount to 24,000 tonne-miles per dwt.
Dry bulk carriers
For dry bulk carriers, tonne-miles data are only available for the five main dry bulks (iron ore, coal, grain,
bauxite and alumina, and phosphate rock), whereas the tonnage data is related to the total bulk carrier fleet.
The productivity presented in Figure 39 is thus an underestimation of the productivity of dry bulk carriers.
This, however, is not a problem for our tonnage projection: if it is assumed that the future tonne-miles related
to the other bulks develop according to the tonne-miles of the five main dry bulks, the tonnage projection
based on the underestimated productivity will still give a good tonnage projection for the dry bulk fleet.
The 2012 productivity value amounts to 23,000 tonne-miles per dwt.