This report details the maritime model, a tool used for analysing future scenarios of the shipping industry, and to estimate the CO2 emissions of the global industry and the share of those emissions that are attributable to the UK. The model considers change of the industry by simulating its growth over time in response to changes in transport demand, macroeconomics (e.g. fuel, carbon price, newbuild price inflation), technology availability, regulation (e.g. regulations on GHG and other air emissions). The model takes inputs for external factors which have been defined in D2.1, and combines them with a series of algorithms to simulate both fleet turn over and activity of the global and UK shipping fleet. The outputs of the model include an estimate of the likely technical and operational specification of ships from 2010-2050 (broken down into categories of ship type, size and age) and the trajectories and attribution of emissions.