The increasing need to reduce greenhouse gas emissions and shift away from fossil fuels has raised an interest for methanol. Methanol can be produced from renewable sources and can drastically lower soot emissions from compression ignition engines (CI). As a result, research and development efforts have intensified focusing on the use of methanol as a replacement for diesel in CI engines. The issue with methanol lies in the fact that methanol is challenging to ignite through compression alone, particularly at low-load and cold starts conditions. This challenge arises from methanol's high octane number, low heating value, and high heat of vaporization, all of which collectively demand a substantial amount of heat for methanol to ignite through compression. One successful project using methanol is the Fastwater project, where a diesel engine was converted to run on methanol, with 3% ignition improver, and installed in the pilot boat Pilot 120SE, that is running in real world conditions off the east coast of Sweden. The aim of this paper is to evaluate the performance of a fuel blend comprising of 97% methanol and 3% ignition improver (MeOH97), as is utilized in the pilot boat, on a heavy duty CI engine test bench. This evaluation involved a comparison with both diesel fuel and non-blended methanol (MeOH100). The results indicated that, in terms of gross indicated efficiency, MeOH97 is on par with diesel for most load conditions and can potentially even surpass it at higher loads. It is only at the lowest tested load that MeOH97 exhibits a drop in efficiency, although combustion remains stable. Furthermore, the results confirm that the addition of a 3% ignition improver significantly improves the combustibility of methanol, particularly at lower loads. Lastly, the use of methanol leads to a noteworthy reduction in NOx emissions without generating any soot emissions.