AFive-YearEmissionAnalysisofaTurkish-FlaggedBitumenTankerafteraSiliconeHybridAntifoulingDrydockRetrofit(M/T‘BIT-03’,2021–2026)

İngilizce (OpenAlex)

This study presents a five-year, monthly operational analysis of a Turkish-flagged bitumen tanker (anonymised due to commercial confidentiality as BIT-03; 14,787 DWT; built 2019; scrubber-equipped) operating mainly in Mediterranean bitumen trade, aiming to be in line with the IMO 2030 decarbonisation targets. Sixty-one monthly observations from January 2021 to January 2026 are extracted from the StormGeo s-Insight platform, with emissions calculated using IMO MEPC.245(66) carbon conversion factors and the Annual Efficiency Ratio (AER) reported per MEPC.336(76). In April-May 2024 the tanker has gone through a drydock retrofit using a silicone hybrid antifouling coating (Hempel Hempaguard X7 family); the supplier’s engineering proposition was a 7.5% annual CO2 emissions reduction, which was ambitious at the time. As 2024 was not the right year to compare due to heavy hull biofouling just before the drydock, the 2025 post-retrofit calendar year was compared against 2023 (the right pre-retrofit baseline); the median monthly AER fell from 15.59 to 13.04 g CO2/(nm·DWT), a 16.4% gross reduction. Decomposing those three components — dirty pre-2024 fouling (5-6 percentage points), the hybrid silicone coating, and a post-drydock JRC eco-mode autopilot upgrade in early 2025 (~1%) — the retrofit-attributable share lies between a 9-11% band, which is in line with the supplier’s proposition. As well, during the same period, the vessel sailed 19.6% more nautical miles while its annual CO2 emissions increased by only 1.7%. The gap between fuel growth (+6.6%) and the CO2 emission increase is somehow explained by the partial bio-diesel substitution in the 2025 fuel mix (236 mt, less than 6% of annual fuel). Thus the case shows a measurable (not total decoupling) but relative decoupling of fuel consumption and emissions after a single-technology antifouling retrofit, and offers a credible pathway toward the IMO 2030 and 2050 decarbonisation targets.