Navalimpianti Tecnimpianti has designed and supplied the stored telescopic davit system for lifeboats, tenders and rescue boats aboard the Ruby Princess.
The installation includes 18 stored power davits for life boats; six stored power davits for tenders; and two stored power davits for rescue boats
The davits design allows the promenade deck to be completely open. This solution is particularly useful when the deck is also used as a passenger walking area and during embarkation operations, according to Navalimpianti. The davit arms are welded below the upper deck and can be extended outboard to lower the life boats as far as the embarkation position in any trim and list condition required by SOLAS regulations.
The necessary hydraulic power to recharge the accumulators and move the davits is produced by six hydraulic power packs, which are arranged in six separate rooms. The hydraulic power is stored inside one accumulator with a suitable number of nitrogen bottles for each davit. Consequently the necessary power for the "abandon the ship" condition is always available and it permits davit extension so that fully loaded boats can be lowered to sea in all trim and list conditions. This hydraulic stored power system is independent of any other power supply on the ship, so that also in case of black out, the davits can be hydraulically extended and the boats lowered.
The davit set includes two telescopic davit arms and one hydraulic winch with the relevant hydraulic equipment. Each davit arm consists of three parts: the fixed frame, the travelling beam and the trolley. The fixed frame is connected to the ship and supports the travelling beam on which the trolley slides with the lower block. The telescopic beams are moved by hydraulic cylinders connected to the stored power system and controlled from the control stand.
The “Navalimpianti WINners type” is a Valves-Remote-Control-System with electro-hydraulic actuators; on each valve is installed the relevant hydraulic actuator to which a micro electro-hydraulic unit is directly connected. The system is characterised by a high modularity; it is in fact possible to design a system employing the modular logic: tork rotative actuators, ram linear actuators, micro power pack electro-hydraulic unit, the rack controller unit denominated Winners Controller Unit (WCU), the controller card (WC), the power supply card and the network.
According to Navalimpianti, the system architecture is founded on three main technological choices: electro-hydraulic actuators (ETork & ERam), intelligent units controller cabinets (WCC) and non-proprietary network based on Lontalk protocol developed by Echelon. This choice excludes the need of hydraulic linkages between the hydraulic station and actuator; the connections are only of electrical type and there are no traditional hydraulic power packs. Each actuator, either of linear or rotating type, is equipped with its own micro electro-hydraulic unit which is operated by an electronic control card.