Self-sufficient ocean cruiser gets efficiency boost
Energy Observer, a vessel that uses fuel cell propulsion while also processing its own hydrogen on board via solar power, recently completed its first transatlantic passage.
Prior to the crossing, the boat was outfitted with new, high-efficiency Autoprop propellers from supplier Bruntons, as well as a pair of Oceanwings wing sails, which consist of two, 12m-tall (39ft) composite masts fitted with 32m2 (345ft2) sails.
According to the Energy Observer team, it took the decision to fit the new propellers after assessing them as the best option to complement the craft’s new ‘wings’, providing a more efficient solution than its existing, fixed pitch, four-bladed props. Bruntons notes that the new propellers use an automatic pitch adjustment system to match their performance to the constant torque delivered by the electric drive across its operating rev range, increasing the overall system efficiency. When purely sailing, and if maximum speed is not essential, the propellers can also be left to turn in the vessel’s wake, providing additional charging for Energy Observer’s batteries. The vessel’s crew enthused that the combination of wings and propellers enabled the craft to reach speeds of up to 14kts in heavy seas.