It is widely acknowledged that the two major interoceanic canals of Panama and Suez play a central role in global trading flows. However, their precise weight for specific commodities such as containers has barely been estimated, as well as the geographical and topological influence of the canals on global freight flows. This study first confirms the high vulnerability of the global maritime network as its connectivity depends on only two major nodes. In reference to existing research on the vulnerability of (transport) networks and based on a global database of containerships movements, this paper proposes measuring the impact of removing the canals on a) the whole network structure and b) on the position of individual ports. Main results point at noticeable changes in the configuration of world flows.