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25m patrol vessel RPA8
Shipyard Kooiman recently received an order for this 25-metre patrol vessel for the Rotterdam Port Authority. The vessel will be delivered in May 2017. The order followed a public tender process in which several builders competed with their designs.
The principal focal points in the tender were the vessel’s complete life-cycle cost, a minimal amount of emissions and a minimum of wave formation. One of the competing shipyards, Shipyard Kooiman, contracted Van Oossanen Naval Architecture for the hull design. The design which best matched with the operational profile – a rarely used top speed of 30 km/h, and a normal cruising speed of 20 km/h – is a combination of two patented innovations launched by Van Oossanen: the Fast Displacement Hull Form (FDHF) and the Hull Vane®.
The concept of the FDHF is rather simple: by avoiding hydrodynamic lift even at high speeds, the vessel stays in displacement mode with almost no running trim, and the complete absence of a “hump speed”. A significant amount of lift is generated however by the Hull Vane®. This lift is angled forward, and therefore produces forward thrust, but it also has a profound impact on the stern wave generated by the vessel, especially at intermediate speeds. Making less waves means burning less fuel, and therefore emitting less CO2, NOx, SOx and particulate matter into the atmosphere, in addition to a smaller propulsion plant and a lower fuel bill of course.
For efficient patrolling at low speeds, the vessel will have a hybrid propulsion installation from Hybrid Ship Propulsion BV. This allows the crew to switch off both main engines and sail with only one small generator running when sailing at speeds up to XX km/h. A lot of attention was also put into ergonomics, providing a safe and comfortable work space for the crew.
Shipyard Kooiman expects the design to become a new benchmark for inland waterway and near-shore patrol and survey vessels.
Thew video below shows a comparison of the RPA8 model in tank tests with and without the Hull Vane®