High frequency Ro-Pax achieves 14.6% fuel savings and emissions reduction

Overview

A North American Ro-Pax operator runs one of the busiest coastal routes. The vessel carries cars, trucks, buses and foot passengers on back-to-back crossings of about 90 minutes, from early morning to past midnight.

To cut fuel and emissions without taking the vessel off the route, the operator partnered with Hullbot to implement proactive grooming fitted around its short overnight layover. The Ro-Pax operator burned 14.6% less fuel, at the same speed and with heavier summer loads.

The challenge: managing biofouling on an always-on vessel

A Ro-Pax on a high-frequency route fouls the whole time it is sailing. The operator’s own records showed fuel use climbing with time since dry dock, with summer being the worst season.

Traditional mitigation methods did not fit the vessel’s schedule:

1. Dry docking: Resets the hull, but takes the vessel off the route, and fouling returns within days.
2. Diver cleaning: Needs longer in-water windows than a short overnight layover allows, and risks damaging foul-release coatings.

The operator needed a way to keep a large hull clean inside short layovers, without cancelling or delaying a single sailing.

The solution: proactive grooming within the overnight layover

Hullbot introduced a managed grooming program built around the vessel’s timetable.

• Grooming within short layovers: Hullbot robots work while the vessel is alongside overnight, so the hull is cleaned around the schedule.
• Full-hull coverage: Every groom covers the flat bottom, sides, rudders, propellers and sea chests.
• Optimal hull condition: Light fouling was removed early, with no hard fouling allowed to develop, maintaining hull efficiency.
• Coating-safe cleaning: Soft contact on early-stage biofilm protects the vessel’s silicone foul-release coating.
• Inspection records: Pre- and post-groom imagery gives the operator a visual record of hull condition after every service.

Measurable results & ROI

• 14.6% fuel reduction and emissions: Measured against historical years of the vessel’s own data, accounting for speed, load, and environmental factors.
• Proven operational seamlessness: Multiple full-hull grooms in months, each one completed during a short overnight layover, with no delays to the timetable.
• A healthier hull: Light fouling was removed early, with no hard fouling allowed to develop.
• ESG alignment: Hullbot proactive grooming helped to avoid hundreds of tons of CO₂ a year on this vessel alone.

Running a fixed-schedule Ro-Pax? Talk to Hullbot about a grooming program built around your layovers.