Carrying out a full generator overhaul on a superyacht of more than 50 metres

Behind every perfect voyage, there are engines and generators that do not fail. And behind them, there is a team that knows them inside out. At Waterline Boat Engineering, we know this well: when we work on unique yachts, we are not only repairing machinery, we are also protecting the experience of navigation by minimizing as much as possible the chance of unexpected issues arising.

One of our latest projects has been the complete overhaul of the main generators on a historic 50-metre superyacht equipped with electric propulsion. A vessel with character, presence, and the technical demands that come with this type of operation. We have been working with its crew and technical team for years, and we know that here there is no margin for error.

On this type of yacht, maintenance is not an option, it is an obligation. Even when the generators are running well, they are reviewed from top to bottom, bolt by bolt. Because it is not just about “starting up”, but about guaranteeing that they will do so every time. It makes no difference whether the yacht is crossing the Mediterranean or preparing for a charter season in the Caribbean. Every system has to respond with precision. And that requires far more than tools: it requires vision, planning, technique, and expertise.

These generators, five in total, all fitted with Scania engines, are responsible for producing the onboard power supply that provides comfort in every corner of the yacht and also feeds the vessel’s propulsion system. Although we are not involved with the Pods or the direct propulsion side, our responsibility is to ensure that electrical generation is stable, safe, and efficient.

An overhaul of this kind means opening everything up. Checking, cleaning, measuring, replacing where necessary, and then reassembling with the precision of a watchmaker. Pistons, injectors, intercoolers, cooling system, exhaust… every component is inspected, cleaned, or replaced depending on its condition.

The most difficult part? Doing all of this inside a yacht. Adapting to confined spaces, planning with third-party companies for the construction of special scaffolding, or even carrying out temporary structural modifications to the vessel in order to remove or move certain pieces of equipment. Coordination with specialist suppliers, from alignment companies to technical paint providers for high-temperature-resistant coatings, is another part of the work we carry out to ensure that everything fits together perfectly.

In this specific case, the overhaul was not carried out simultaneously on all five generators, but rather in stages, depending on the yacht’s overall schedule and the work of other technical teams. A process like this can take between one and two months per generator, depending on the model and the number of cylinders in each unit.

Beyond the mechanical work, there is something our clients value even more: peace of mind. Knowing that they can call us from anywhere in the world and that we will respond. Knowing that behind the Waterline uniform there are people who are committed, who know the vessel, and who understand the level of demand of these owners, captains and crews. Because we do not work with excuses, but with solutions.

This project is just one example. But it represents very well what we do every day. We are specialists in marine engines and generators, yes. But above all, we are a team that takes care of every detail, responds when needed, and works to ensure that everything functions where it matters most: at sea. We are proud to have been part of this project and to continue being a benchmark in the maintenance of marine generators on large yachts.