The recently delivered OE72 is a state-of-the-art innovative hybrid propulsion yacht. When the project started over 3 years ago the solution providers for hybrid propulsion for this size of catamaran was fairly limited and most lacking experience for our type of installation. At the same time OQS being a small agile yard that mainly work with a network of suppliers and contractors we needed to team up with a supplier that could provide a solution that could comply with our long list of requirements on the system and installation.
Together with the highly experienced client, we decided to go for a Torqeedo Deep Blue system. One of the main requirements was redundancy, but also the setup of the system to be installed. With the modular setup we got from Torqeedo (naturally together with twin engine installation in the catamaran) the level of redundancy for power supply and energy management requirements were met without going to a complete custom system. We however we had a lot of adjustments and modifications to be done to get the system up and running. Requirements of max motoring speed and comfort level of battery capacity made the system we have on the boat much bigger than a normal cruising catamaran would need, but again the requirements to were met in terms of silent hours, long range motoring speed and top speed of the boat.
We did extensive testing in Jakobstad and continued testing and fine tuning the system during the first couple of months of sailing with the boat, both in very high seas with over 40 knots maximum wind speed and in several days of only motoring due to no wind and the boat coped well with all conditions so far.
One of the requirements we had on the system was regeneration and getting to harvest energy during sailing. During the first months of sailing, we never got any good results from regeneration testing. The challenges to the testing were mainly since system parameters are different for different boats; we compared what parameters we should test against and how the props react in different speed with waves and so forth. We managed to get it working and during the last weeks of sailing and we got regeneration of 5-12kW total through both motors and with normal usage of the yacht. With dishwasher on, coffeemaker and tea water boiling we still managed to increase the state of charge in the batteries so under certain conditions the boat can generate more energy than it uses, and 0-emission sailing is achieved.