Seagoing vessel with two two-stroke propulsion engines

Abstract

Seagoing vessel (10) with two slow-running two-stroke engines (20, 20') arranged offset transversely to the longitudinal axis of the vessel, which are each connected by means of a propeller shaft (30, 30') to a ship's propeller (40, 40') arranged at the stern, wherein the propeller shafts (30, 30') are each arranged at an acute angle to the longitudinal axis of the vessel, directed outwards in the direction of the stern, characterized in that the two-stroke engines (20, 20') are arranged one behind the other in the longitudinal direction of the seagoing vessel (10).

Description

[0001] The invention relates to a seagoing vessel with two slow-speed two-stroke engines arranged transversely to the ship's longitudinal axis, offset from each other, each connected by a propeller shaft to a ship's propeller arranged at the stern. The propeller shafts are each arranged at an acute angle to the ship's longitudinal axis, pointing outward toward the stern. In particular, the invention relates to such a seagoing vessel designed as a RoRo or RoPax vessel, i.e., a seagoing vessel designed for the transport of rolling cargo with or without passengers, the latter also being referred to as a RoPax ferry, combi-ferry, or combi-carrier.

[0002] A RoRo vessel of this design is known, for example, from the Ark Dania. This vessel features a two-stroke propulsion engine system consisting of two MAN 8S40ME-B9 engines, arranged directly next to each other and symmetrically to the ship's longitudinal axis. The two propeller shafts located at the rear are oriented at an acute angle to the ship's longitudinal axis, outward toward the stern, i.e., deviating from the ship's longitudinal axis and toward the side of the ship. The disadvantage of this vessel is its very wide engine bay, which severely constricts the vehicle deck in the center of the ship, significantly impairing the flow of loading and unloading.

[0003] In addition, there is the problem that operators of seagoing vessels face technical challenges in reducing emissions due to the climate targets set by the UN Maritime Organization (IMO), for example through the use of climate-neutral fuels such as green ammonia or green methanol.

[0004] For example, in 2015, the RoPax ferry "Stena Germanica" was converted, at considerable technical and financial expense, so that its two four-stroke diesel engines could run on both marine diesel and methanol in dual-fuel mode, thus complying with the stricter environmental regulations that came into force on January 1, 2015. In addition, the "Lindanger" class of tankers was introduced in 2016. Its propulsion system is a more advantageous dual-fuel two-stroke engine powered by methanol. Market-ready two-stroke marine propulsion engines already exist for the use of methanol and ammonia. The use of such fuels in four-stroke engines is technically significantly more demanding, and market readiness lags behind that of two-stroke propulsion engines.

[0005] Although Mitsui OSK Lines is known to have plans to build a RoPax vessel with a two-stroke propulsion engine, this is only a ferry for domestic voyages, for which the international safety regulations of the IMO under SOLAS, such as the Safe Return to Port requirement for redundant propulsion, are not mandatory. A fundamental problem is that, for example, RoPax vessels (unlike tankers) require two redundant propulsion systems for reasons of reliability, but these require a lot of space.

[0006] The object of the invention is therefore to create a seagoing vessel with a propeller drive having two two-stroke engines, the construction of which requires only a small amount of work and material, whereby the drive should only require a small amount of space within the seagoing vessel.

[0007] This object is achieved according to the invention by the seagoing vessel having the features of claim 1. The subclaims reflect advantageous embodiments of the invention.

[0008] The basic idea of ​​the invention is to create a seagoing vessel with a two-stroke propulsion system based on a twin engine system slightly offset one behind the other in the longitudinal direction of the vessel, with the two shaft trains and the propellers integrated into the system. This measure makes it possible to minimize the space required across the width of the seagoing vessel. At the same time, the arrangement according to the invention facilitates the spatial separation of the two propulsion engines while simultaneously meeting damage stability regulations.

[0009] According to the invention, a seagoing vessel is proposed with two slow-running two-stroke engines arranged offset transversely to the longitudinal axis of the vessel, which are each connected by means of a propeller shaft to a ship's propeller arranged at the stern, wherein the propeller shafts are each directed outwards at an acute angle to the longitudinal axis of the vessel in the direction of the stern and the two-stroke engines are arranged one behind the other in the longitudinal direction of the seagoing vessel.

[0010] According to the invention, two separate drive trains are therefore provided, it being understood that in this arrangement, one drive train must be connected to one two-stroke engine and the associated ship's propeller by means of a propeller shaft which is longer than the propeller shaft of the other drive train connecting the other two-stroke engine to the other ship's propeller.

[0011] The propeller shafts are each arranged at an acute angle to the ship's longitudinal axis, with the propeller shafts running approximately outwards (towards the respective side of the ship) and deviating from the ship's longitudinal axis. In particular, each propeller shaft runs outwards to the side of the ship to which the associated two-stroke engine is offset. This creates an angle between the propeller shafts which, from a hydrodynamic point of view, should preferably be kept small, particularly preferably ≤ 5°. This can easily be achieved by designing the distance between the propellers and the two-stroke engines connected by the propeller shafts as large as possible. In particular, the two-stroke engines are preferably arranged in the ship's mid-ship with respect to the longitudinal axis, particularly preferably towards the bow, so that the influence of a propeller angle deviating from the ship's longitudinal axis remains small.In this case, in the case of a rigid arrangement between the time-stroke engine, propeller shaft and propeller, it is necessary that the longitudinal axes of the two-stroke engines are not parallel but also aligned at an angle to each other.

[0012] The acute angle formed by the propeller shafts to the ship's longitudinal axis is preferably identical, so that the necessary offset of the two-stroke engines along the ship's longitudinal axis also provides sufficient space.

[0013] According to a further preferred embodiment, the two-stroke engines have identical performance parameters, i.e. are essentially identical, i.e. of the same construction or of the same type.

[0014] Furthermore, it is preferably provided that the width occupied by the two-stroke engines arranged one behind the other in the longitudinal direction of the seagoing vessel in a direction transverse to the longitudinal direction of the seagoing vessel is less than twice the width of a two-stroke engine. Most preferably, the width occupied by the two-stroke engines corresponds to a maximum of one and a half times the width of a two-stroke engine.

[0015] In particular, according to a further preferred embodiment, the two-stroke engines are arranged in compartments that are separated from one another. The compartments are specifically designed as separate engine rooms, with each two-stroke engine being able to be operated independently of the other two-stroke engine (in an emergency). In the simplest case, the compartments are separated by a partition wall designed as a bulkhead, which is particularly designed as a firewall. Specifically, all walls forming the respective compartment, including the ceiling and floor, are designed as bulkheads, thus ensuring a high level of reliability of the seagoing vessel even with limited space requirements.

[0016] Finally, due to the relatively small space requirement of the propulsion system and its high reliability, the invention is suitable for the design of a RoRo or RoPax ship, so that the seagoing vessel designed according to the invention is particularly preferably a RoRo or RoPax ship.

[0017] The invention will be explained in more detail below with reference to a particularly preferred embodiment shown in the accompanying drawings. They show: Fig. 1 shows a longitudinal section of a preferred embodiment of a seagoing vessel according to the invention; Fig. 2 a plan view of the Fig. 1 shown embodiment at the level of the two-stroke engines; and Fig. 3 a cross-section through the previously shown seagoing vessel in the area of ​​the two-stroke engines.

[0018] Fig. Figure 1 shows a longitudinal section of a preferred embodiment of a seagoing vessel according to the invention. In particular, Fig. 1 a seagoing vessel 10 with two slow-running two-stroke engines 20, 20', which are arranged one behind the other in the longitudinal direction of the seagoing vessel 10 and - as in the Fig. 2 - are arranged offset transversely to the longitudinal axis of the ship, each two-stroke engine 20, 20' being connected by means of a propeller shaft 30, 30' to a respective ship propeller 40, 40' arranged at the rear. It can be clearly seen that one two-stroke engine 20' is connected to one ship propeller 40' by means of a propeller shaft 30', which is longer than the propeller shaft 30 connecting the other two-stroke engine 20 to the other ship propeller 40.

[0019] The two-stroke engines 20, 20', which in the exemplary embodiment are two-stroke engines of the same type, are preferably arranged in compartments (not shown) that are separated from one another, so that it is ensured that an engine failure of one two-stroke engine 20, 20' cannot spread to the other two-stroke engine 20, 20' and the ship remains maneuverable.

[0020] The propeller shafts 30, 30', which are specially designed to rotate in opposite directions, are - as can be seen from Fig. 2 - are each arranged at an acute angle to the longitudinal axis of the ship, the acute angle formed by the propeller shafts 30, 30' to the longitudinal axis of the ship being essentially identical.

[0021] Fig.Figure 3, which depicts a cross-section through the previously shown seagoing vessel in the area of ​​the two-stroke engines, illustrates that the width occupied by the two-stroke engines 20, 20' arranged one behind the other in the longitudinal direction of the seagoing vessel 10 in a direction transverse to the longitudinal direction of the seagoing vessel 10 is less than twice the width of a two-stroke engine 20, 20'. Thus, a space-saving arrangement of the two-stroke engines 20, 20' can be achieved with only a minor impact on the loading capacity with regard to cargo transport and passenger transport.

Claims

[1] Seagoing vessel (10) with two slow-running two-stroke engines (20, 20') arranged offset transversely to the vessel's longitudinal axis, each of which is connected by means of a propeller shaft (30, 30') to a ship's propeller (40, 40') arranged at the stern, the propeller shafts (30, 30') each being arranged at an acute angle to the vessel's longitudinal axis, directed outwards in the direction of the stern, characterized by that the two-stroke engines (20, 20') are arranged one behind the other in the longitudinal direction of the seagoing vessel (10). [2] Seagoing vessel (10) according to claim 1, characterized by that the two-stroke engines (20, 20') are arranged in compartments separated from one another. [3] Seagoing vessel (10) according to one of the preceding claims, characterized by that the acute angle formed by the propeller shafts (30, 30') to the longitudinal axis of the ship is identical. [4] Seagoing vessel (10) according to one of the preceding claims, characterized bythat the angle between the propeller shafts (30, 30') is a maximum of 5°. [5] Seagoing vessel (10) according to one of the preceding claims, characterized by that the two-stroke engines (20, 20') have identical performance parameters. [6] Seagoing vessel (10) according to one of the preceding claims, characterized by that the width occupied by the two-stroke engines (20, 20') arranged one behind the other in the longitudinal direction of the seagoing vessel (10) in a direction transverse to the longitudinal direction of the seagoing vessel (10) is less than twice the width of a two-stroke engine (20, 20'). [7] Seagoing vessel (10) according to one of the preceding claims, characterized by that the seagoing vessel (10) is a RoRo or RoPax vessel.

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