Two marine ferry vessels' operating characteristics were investigated to determine the technical feasibility of applying emission reduction strategies. These vessels, the Alice Austen and the Andrew J Barberi, were instrumented with appropriate sensors and data were collected over a two-month period. The vessel operation, dependent on vessel direction, was divided into four discrete modes: idle, acceleration, cruise, and manoeuvring. The NO brake-specific emissions of the Alice Austen and the Andrew J Barberi during cruise mode were estimated to be 9.1-11.8g/bhp-hr and 10.8-11.5g/bhp-hr, respectively. The exhaust manifold temperature during operation of the Alice Austen and the Andrew J Barberi ranged from 145-443°C and 110-400°C, respectively. On a vessel basis, Andrew J Barberi produced 3645g/mile of NO emissions, while the Alice Austen produced 1599g/mile. From 85-90% of NO was produced at temperatures suitable for selective catalytic reduction (SCR) use and therefore the NO emissions could potentially be controlled. The Alice Austen and Andrew J Barberi were determined to be candidates for SCR systems. The Andrew J Barberi had low exhaust manifold temperatures and would need an optimised low temperature SCR.