AU2009100540A4 - Redundancy of Propulsion for Sea-Going Vessels - Google Patents

Description

AUSTRALIA ORIGINAL COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: Redundancy of Propulsion for Sea-Going Vessels Name of Applicant: Austal Ships Pty Ltd Actual Inventor(s): Neville Anthony Armstrong Address for service: WRAYS Ground Floor, 56 Ord Street West Perth WA 6005 Attorney code: WR The following statement is a full description of this invention, including the best method of performing it known to me:- -2 REDUNDANCY OF PROPULSION FOR SEA-GOING VESSELS Field of the Invention This invention relates to multi-hulled vessels, such as trimarans and pentamarans, having a main hull and at least one side hull on each side of the main hull. More 5 particularity, the invention is concerned with propulsions systems for such vessels. The invention has been devised particularly, although not necessarily solely, for high speed commercial and military vessels, such as ferries, configured as trimarans for passenger and cargo transport, including vehicle transport. 10 Background Art The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application. 15 Sea-going vessels are generally constructed with an internal compartment which houses the main propulsion machinery, typical examples of which are diesel engines although other internal combustion engines may be used, such as gas turbines. This internal compartment, generally known as a main machinery space, or engine room, would normally be arranged and outfitted with systems so as to 20 meet the regulatory requirements of the country in which the vessel is registered. The main engines would normally drive a shaft passing through the after engine room bulkhead to the after part of the vessel where it would be connected to the propulsor, which may be a propeller or other variation such as an impeller within a waterjet.

-3 On conventional vessels having a single hull, there may be one or more main engines. The engine(s) may be contained within a single engine room, or may be split into two or more engine rooms for convenience. Where vessels are designed for high speeds, it is generally desirable for reasons 5 of efficiency to have a hull which is long and thin. However, this leads to a lack of stability and the vessel might easily capsize. Therefore, many high speed vessels are designed with two or more hulls which are long and thin, or long and narrow, and are arranged in such a way as to provide improved stability. Typical examples of such vessels are the two-hulled catamaran and the three-hulled trimaran. 1 The long and narrow hull arrangement may provide efficient levels of power for the desired speed, but it can become difficult to fit the main engines into a narrow hull owing to the lack of physical space. In many existing catamarans, the required levels of power can only be provided by four or more engines, although there is insufficient room for two engines to be mounted side-by-side, 15 necessitating one to be fitted forward of the other, and the drive shaft from the forward engine passing alongside the after engine. A trimaran vessel with one larger main hull and two small side hulls or amahs generally has the propulsion machinery located in the main hull. The long and narrow main hull has insufficient width to accommodate all of the main engines 20 alongside each other. Consequently, it may be necessary to longitudinally stagger the engines with respect to each other. An earlier proposal for addressing this problem incorporate two engine rooms with two engines fitted in the forward engine room and two fitted in the after engine room. The drive shafts from the forward main engines pass through the 25 after engine room and are connected to the waterjet propulsion. The problem with this arrangement lies with redundancy of the propulsion system should there be a fire or flooding in the after engine room. In case of fire in the after engine room accommodating more than one engine, it is entirely likely that -4 the engines will become inoperative, and the shaftlines passing through the after engine room, and their associated bearings and supports, will also become inoperative, effectively disabling the entire propulsion system and rendering the vessel inoperative. 5 A simple solution to this issue might be to enclose the shaftlines in a fireproof structure, such as a shaft tunnel, commonly used on large monohull conventional sea-going craft. However, most of the high-speed catamarans and trimarans are manufactured from aluminium for lightness of construction, and aluminium is vulnerable to damage when exposed to heat generated by fire, which leads to 10 difficulties of manufacture of a suitable shaft tunnel. It is against this background and the problems and difficulties associated therewith, that the present invention has been developed. Disclosure of the Invention According to a first aspect of the invention there is provided a multi-hulled vessel 15 comprising a main hull and a propulsion system for delivering propulsive power to the main hull, the propulsion system comprising two or more engines, and the main hull comprising two engine rooms disposed in side-by-side relation, each engine room accommodating at least one of the engines, each engine room being isolated from the other and adapted to provide a watertight and fire-protected 20 environment. The number of engines required is selected to provide redundancy of propulsion for the vessel. Preferably, the two engine rooms are separated from each other by a bulkhead disposed therebetween.

- 5 Preferably, the propulsion system further comprises a drive transmission system for delivery of rotational power from each engine to a propulsion device such as a propulsor, the drive transmission system comprising a driveshaft. Preferably, the main hull further comprises an aftermost compartment between 5 the engine rooms and the stern of the main hull providing a watertight and fire protected environment, whereby each driveshaft extends from the respective engine room to the propulsion device through the aftermost compartment. The propulsion system may comprise one or more further engines in at least one of the engine rooms to provide a plurality of engines in the room. The engines 10 may be disposed in a longitudinally staggered arrangement in the engine room. Where there are engines disposed in longitudinally staggered relation within a respective engine room, the driveshaft extending from each engine disposed forwardly of another engine in that compartment may pass alongside the rearwardly disposed engine. 15 The two engine rooms need not necessarily be of the same size. Each engine room can be of a size to accommodate the machinery and equipment required to be accommodated therein. There may also be one or more additional engine rooms if required. The additional engine rooms can be disposed forward or aft of the two engines rooms 20 previously mentioned. The engines may be of any appropriate type. Typically, the engines are intemal combustion engines such as diesel engines, although other combustion engines such as gas turbines could be used. Preferably multi-hulled vessel is configured as a trimaran having two side hulls on 25 opposed sides of the main hull.

-6 Brief Description of the Drawings The invention will be better understood by reference to the following description of one specific embodiment thereof as shown in the accompanying drawings in which: 5 Figure 1 is a schematic rear elevation of a multi-hulled vessel according to the embodiment configured as a trimaran having a main hull and two side hulls; Figure 2 is a schematic plan view of the main hull and two side hulls, illustrating in particular engine rooms in the main hull; and 10 Figure 3 is a view similar to Figure 2, illustrating in particular a propulsion system for the main hull comprising engines in the engine rooms. Best Mode(s) for Carrying Out the Invention The embodiment shown in the drawings is directed to a multi-hulled vessel configured as a trimaran 10. The trimaran 10 according to the embodiment is a 15 high speed, commercial, sea-going vessel operating as a ferry for passenger, and cargo transport, including in particular vehicle transport. Typically, the trimaran 10 is of a size in the order of 80 to 130 metres, although it is of course not limited thereto. The trimaran 10 comprises an understructure 11 and a superstructure 13, both 20 constructed primarily of aluminium. The waterline in relation to the understructure 11 is identified in Figure 1 by reference numeral 14. The understructure 11 comprises a centrally located main hull 15 and two laterally spaced side hulls 17, commonly known as amahs.

-7 The understructure 11 further comprises two integral bridge structures 19 interconnecting the main hull 15 and the two side hulls 17. The bridge structures 19 and the hull 15, 17 cooperate to provide a deck surface 21 above which the superstructure 13 is located. The bridge structure 19 and the hulls 15, 17 5 cooperate to provide two tunnels 23 on opposed sides of the main hull 15. The main hull 15 has a forward end terminating at a bow 25 and an aft end terminating at a stem 27 configured as a transom 29. Similarly, each side hull 17 has a forward end terminating at a bow 31 and an aft end terminating at a stern 33 configured as a transom 35. 10 A propulsion system 37 is provided for delivering propulsive power to the main hull 15. The propulsion system 37 comprises a plurality of propulsion engines 39 and a drive transmission system 41 for delivery of rotational power from each engine 39 to a propulsion device such as a propulsor 42 at the stern 27. In this embodiment, the propulsors 42 comprise steerable water jets. Each drive 15 transmission system 41 comprises a driveshaft 43 and an associated gearbox 44. In this embodiment, the engines 39 comprise diesel engines, although other suitable types of engines may be used, including gas turbines. In the arrangement illustrated, there are three propulsion engines 39. The trimaran 10 can, of course, be equipped with more than three engines if required. 20 Redundancy of propulsion for the trimaran 10 is afforded by the presence of two or more engines. The main hull 15 incorporates first and second engine rooms 45, 47 disposed in side-by-side relation and separated by a bulkhead 49, as best seen in Figure 2. The engine room 45, 47 are isolated from each other, and provide watertight, 25 airtight and fire-protected environments for accommodating the engines 39. In the arrangement illustrated, the first engine room 45 accommodates two of the engines 39 and the second engine room 47 accommodates the third engine 39. Because of space constraints, the engines 39 in the first engine room 45 are staggered longitudinally in relation to each other such that one is a forward engine and the other an aft engine. With this arrangement, the driveshaft 43 of the forward engine passes alongside the aft engine. In the arrangement shown, the first engine room 45 is wider than the second engine room 47 in order to 5 accommodate the driveshaft 43 of the forward engine passing alongside the aft engine, as shown in Figure 3. This is achieved by offsetting the bulkhead 49 with respect to the central longitudinal axis of the mail hull 15. The main hull 15 also incorporates an aftermost compartment 51 between the engine rooms 45, 47 and the stem 27 through which the driveshafts 43 extend. 10 The aftermost compartment 51 provides a watertight, airtight and fire-protected environment through which the driveshafts 43 extend. In certain applications, a longitudinal bulkhead (not shown) can be installed in the aftermost compartment 51 to divide it into two sub-compartments disposed in side-by-side relation, with each sub-compartment providing a watertight, airtight 15 and fire-protected environment. Each sub-compartment would accommodate at least one of the drive shafts 43. The superstructure 13 is configured to provide passenger and cargo transport, including vehicle transport. In the arrangement illustrated, the superstructure 13 provides a vehicle space 61 above the understructure 11 and between the 20 outboard sides 63 of the trimaran 10, and a passenger accommodation space 65 above the vehicle space 61. The deck surface 21 provides a vehicle deck 67 for the vehicle space 61. With this arrangement, the vehicle deck 67 is located above the engine rooms 45, 47 within the main hull 15. The vehicle deck 67 incorporates a vehicle accommodation area 25 and lanes required for vehicle movement. From the foregoing, it is evident that the present embodiment provides a simple yet highly effective arrangement which provides redundancy of propulsion and - 9 which can continue to deliver some propulsion for the vessel in the event of a fire or flooding in one of the engine rooms. It should be appreciated that the scope of the invention is not limited to the scope of the embodiment described, and that various changes and modification may be 5 made without departing from the scope of the invention. Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. 10

Claims (5)

1. A multi-hulled vessel comprising a main hull and a propulsion system for delivering propulsive power to the main hull, the propulsion system comprising two or more engines, and the main hull comprising two engine rooms disposed in side-by-side relation, each engine room accommodating at least one of the engines, each engine room being isolated from the other and adapted to provide a watertight and fire-protected environment.

2. The multi-hulled vessel according to claim 1 wherein the two engine rooms are separated from each other by a bulkhead disposed therebetween.

3. The multi-hulled vessel according to claim 1 or 2 wherein the propulsion system further comprises a drive transmission system for delivery of rotational power from each engine to a propulsion device, the drive transmission system comprising a driveshaft, and wherein the main hull further comprises an aftermost compartment between the engine rooms and the stern of the central hull providing a watertight and fire-protected environment, whereby each driveshaft extends from the engine room to the propulsion device through one of the aftermost compartments.

4. The multi-hulled vessel according to claim 1, 2 or 3 further comprising one or more further engines in at least one of the engine rooms to provide a plurality of engines therein, the plurality of engines being disposed in a longitudinally staggered arrangement in the engine room.

5. The multi-hulled vessel according to any one of the preceding claims of aluminium construction.