Designed to deliver unmatched performance and stability, Xiren’s groundbreaking hull form significantly reduces drag, enabling the vessel to travel faster, further, and more comfortably in challenging sea states.
Leveraging proven off-the-shelf technology in a novel way, Xiren’s engineering advancements set a new benchmark for seakeeping and efficiency, making their vessels not only technically superior but also exquisitely progressive in design.
For over 50 years Griffon Hoverwork has supplied governments and organisations in over 40 countries with built-to-class, marine grade aluminium hovercraft and military grade fast attack crafts. Providing the world’s best in search & rescue, passenger transport, commercial operations and defence.
Our relationship with Griffon Hoverwork has proven to be hugely successful with their project engineering capability proving to be second to none, offering first class skills in marine and electrical engineering, training and support. Griffon have been central to the development, design, testing and feasibility process steps Xiren have had to work through to reach a steadfast position of having complete confidence in the performance of our newly designed hull form, validated and verified by the very top naval architects and marine engineers within Griffon Hoverwork.
Griffon Hoverwork is located on the UK’s south coast in a 50,000sqft facility capable of end-to-end production with manufacturing capability that would see upwards of 6 Xiren platforms in staggered build, simultaneously.
Adrian Went, Managing Director at Griffon Hoverwork and Mark Downer, Director of Engineering both occupy positions on the board of Xiren (Toro Commercials LTD).
With the craft operating either as a luxury passenger vessel, high performance sports day boat or as a defence vessel, the load cycle of any proposed engines would have to meet a minimum requirement. Assuming the craft will operate a maximum of 12 hours per day, for 80% of the days in a year (292 days), the estimated typical annual usage would be 3504 hours. This immediately limits engine selection to either a ‘High Load Factor’ or ‘Unrestricted Continuous’ engine operation rating. These are defined below as:
High Load Factor: Average load: 60 – 80 % of rated power; Rating definition: ICFN, fuel stop; Typical annual usage: 5000 hours.
Unrestricted Continuous: Intended for continuous use in applications requiring uninterrupted service at full power. Typical annual usage = unlimited.
For reference, unrestricted continuous rated engines are traditionally installed in work boats, tugs and barges and therefore may be excessive in this application, but remains a viable option.
The ideal engine would also require a high power-to-weight ratio, low weight and spatial volume and sensible fuel consumption and emission standards. Marine diesel engines from various reputable suppliers such as MTU, MAN, Cummins and others were combined in a matrix where key variables and dimensions were directly compared.
The selection process concluded with the MTU BOS 2000-series M72 engine as the ideal engine for the application. The engine product range spans from a V8 producing 965hp (craft total: 1930hp) to a V16 that outputs 1930hp (craft total: 3860hp) and is rated for “High Load Factor” operations. The power-to-weight ratio of the M72 engine is exceptional, approximately 12% greater than the average of the other high load factor alternatives whilst also maintaining a slender volume package.
The hull form has been designed to allow for the vessel to house V10, V12 or V16 engines depending on performance requirement.
Kongsberg jets were selected due to the smaller increments within the product range and better power-to-weight ratio. It is important that the power of the waterjets are closely matched to the engine power, as there would be a risk of a weight penalty in carrying a waterjet too large for a given engine. The flexibility in the Kongsberg S3/CA range reduces this risk. As an example, if the M72 V10 (1250hp) was selected as the engine, the compatible waterjets would be the Kongsberg S36-3/CA (1273hp) and the Hamilton Jet HTX 42 (1743hp). The Kongsberg option is more closely matched to the engine and each waterjet weighs 347kg less than the HTX 42.
Hamilton Jets do have potential and are not completely ruled out. The new HTX range has some significant advantages over the Kongsberg S3/CA range. The HTX has superior directional control and thrust available for low speed and high speed turns. It also has an installation advantage with all the hydraulics mounted to the waterjet as opposed to in the engine for the Kongsberg. However, there are only a limited number in the series at this time. Unless the engine power conveniently pairs closely to one of the few HTX models available, this option may not be the most efficient.
