A short post in Naval News that reported the deployment of a Schiebel Camcopter UAS on a Finnish Coast Guard Cutter prompted me to look up the cutter involved, and it proved interesting for a couple of reasons,
- its unique propulsion system and
- the fact that it can break ice in spite of a bulbous bow.
Wartsila.com provides the information (excerpt below).
“TURVA is powered by three environmentally friendly Wärtsilä 34DF series dual-fuel engines capable of burning both diesel fuel as well as liquefied natural gas (LNG). For redundancy and safe return to port, the engines are arranged in two independent engine rooms divided by a watertight bulkhead. In the aft engine room, a 12-cylinder Wärtsilä 12V34DF producing 6400kW is mechanically coupled to a controllable pitch propeller. In the forward engine room, two 6L34DF generating sets with an output of 3000kW each produce power for two electrically-driven Azipull AZP120CP thrusters. If the forward engine room is damaged, the shaft generator coupled to the bigger engine can be used to produce electricity for the azimuth thrusters, which are required for steering the vessel as she has no separate rudders, and other onboard systems. Since the azimuth thrusters are powered by electric motors and the centerline shaft is mechanically coupled to the main engine, the propulsion system as a whole could be referred to as “combined diesel-electric and diesel” (CODLAD). TURVA is the first ship fitted with this type of propulsion arrangement – two azimuth thrusters and a centerline shaft – which was originally developed for icebreakers and icegoing LNG carriers. For maneuvering and DP2 class dynamic positioning, the ship has a transverse bow thruster and a retractable azimuth thruster in the bow.
“The service speed of the vessel will be 18 knots and despite her bulbous bow she will also be capable of breaking level ice up to 0.80m in thickness. With a bollard pull of approximately 100t, TURVA is capable of towing even the largest tankers regularly sailing in the Baltic Sea.“