A method comprising: obtaining data identifying a first marine vessel and data identifying a voyage to be undertaken by the first marine vessel, the data identifying the voyage comprising an identification of a leg of the voyage, the leg of the voyage having an arrival port and a departure port; computing a fuel consumption estimate using a predictive model, the predictive model being configured to receive as input the data identifying the first marine vessel and the data identifying the voyage to be undertaken, including the identification of the leg of the voyage, parameters for the predictive model being fitted using historical data for a plurality of marine vessels and a plurality of voyages, the historical data comprising, for each of the plurality of marine vessels: data identifying the marine vessel; data identifying a network leg traversed by the marine vessel; and a recorded fuel consumption for the marine vessel traversing the identified network leg; and determining an amount of fuel to be supplied to the first marine vessel for the voyage to be undertaken, based on the fuel consumption estimate, wherein the first marine vessel is configured to consume a plurality of fuel types, and wherein computing the fuel consumption estimate using the predictive model comprises computing fuel consumption estimates for the plurality of fuel types, wherein computing fuel consumption estimates for the plurality of fuel types comprises: computing a first fuel consumption estimate for a first fuel type using a first predictive model; computing a second fuel consumption estimate for a second fuel type using a second predictive model, and determining the amount of fuel comprises determining an amount of each of the first and second fuel types that are to be supplied to the first marine vessel based on the respective first and second fuel consumption estimates. obtaining data identifying a first marine vessel and data identifying a voyage to be undertaken by the first marine vessel, the data identifying the voyage comprising an identification of a leg of the voyage, the leg of the voyage having an arrival port and a departure port; computing a fuel consumption estimate using a predictive model, the predictive model being configured to receive as input the data identifying the first marine vessel and the data identifying the voyage to be undertaken, including the identification of the leg of the voyage, parameters for the predictive model being fitted using historical data for a plurality of marine vessels and a plurality of voyages, the historical data comprising, for each of the plurality of marine vessels: data identifying the marine vessel; data identifying a network leg traversed by the marine vessel; and a recorded fuel consumption for the marine vessel traversing the identified network leg; and data identifying the marine vessel; data identifying a network leg traversed by the marine vessel; and a recorded fuel consumption for the marine vessel traversing the identified network leg; and determining an amount of fuel to be supplied to the first marine vessel for the voyage to be undertaken, based on the fuel consumption estimate, wherein the first marine vessel is configured to consume a plurality of fuel types, and wherein computing the fuel consumption estimate using the predictive model comprises computing fuel consumption estimates for the plurality of fuel types, wherein computing fuel consumption estimates for the plurality of fuel types comprises: computing a first fuel consumption estimate for a first fuel type using a first predictive model; computing a second fuel consumption estimate for a second fuel type using a second predictive model, and determining the amount of fuel comprises determining an amount of each of the first and second fuel types that are to be supplied to the first marine vessel based on the respective first and second fuel consumption estimates. computing a first fuel consumption estimate for a first fuel type using a first predictive model; computing a second fuel consumption estimate for a second fuel type using a second predictive model, and determining the amount of fuel comprises determining an amount of each of the first and second fuel types that are to be supplied to the first marine vessel based on the respective first and second fuel consumption estimates.