A catamaran typically has an Integrel system fitted to each engine to provide redundant operation, however a dual installation is not mandatory on a cat.
The Integrel system is self-organising and will run with two interconnected generators, sharing the load as needed with no user intervention. A dual system provides redundancy and balanced engine running hours; it can also charge multiple battery banks twice as fast as a single system and can support high continuous loads.
A single system fitted on a twin-engine boat performs perfectly well, but takes longer to charge multiple battery banks. If the engine is run in generator only mode when only one engine is fitted with an Integrel generator, it will accumulate more hours than the other engine.