Damen Shipyards, Gorinchem, The Netherlands, is building the world’s first full electric harbor tug — RSD-E 2513 — for delivery in 2021.
Last summer, a ceremony was held at Damen Song Cam Shipyard in Vietnam to mark the keel-laying of the first all-electric 24.73mx13.13m (81'x43') RSD-E Tug 2513 for the Ports of Auckland in New Zealand.
“What makes this a pivotal event in the 220-year history of tugboats is that when launched, the vessel will be the first, fully electric tug with 70 tons of bollard pull in existence,” Damen officials said in a report released in 2020. “This potentially heralds a new era of emissions-free operations in a critical area of maritime activity and marks a big step forward both for Damen and for a sustainable future in harbor and other maritime operations worldwide.”
The reversed stern drive (RSD) tug design has a bow on the fore and aft side of the hull. As a result, the tug can operate “bow first” at the front side and at the aft side of a to be assisted vessel. Twin fin skegs give the tug maneuverability and course stability despite its small length/beam ratio. Compact outer dimensions make the tug ideal for maneuvering in confined harbors and locks. The combination of high freeboard, large bow height fore and aft, wide beam, low VCG and big down flooding angles are designed to make the vessel a safe harbor/terminal tug.
The RSD-E can generate a maximum indirect steering force of 75 tons, a maximum indirect braking force of 100 tons and is compliant to the latest stability rules and regulations for a bollard pull up to 90 tons in all loading conditions, the report said. The compact heavy duty hydraulically driven DMC winch situated on the big obstacle free fore deck is used to transfer the massive forces through the synthetic towing wires on the to be assisted vessels.
Primary fuel needs come from electric shore power that can recharge battery capacity within two hours. The tug will be able to achieve 70 tons bollard pull at 12 knots on battery power for at least 30 minutes or 40 tons bollard pull at 11 knots for an ever longer period of time.
The RSD-E tug features is an Echandia Marine battery system based on Toshiba LTO battery modules.
Twin Caterpillar IMO Tier III diesel engines connected to Leroy Somer generators provide backup ship’s service power and power an optional FFS firefighting pump. The tug can operate with reduced emissions as a hybrid using the IMO Tier III compliant back-up generator/firefighting sets in combination with the batteries. This mode of operation is used for operations where an autonomy is required that can’t be achieved on the installed battery capacity alone, according to the report.