Asymetric towing staple

Abstract

A vessel for towing is disclosed, comprising a hull comprising a deck, two propulsion systems arranged along the central longitudinal axis of the hull and a towing staple for guiding a towline. The towing stable comprises outer and inner towline stoppers, arranged between the two propulsion system for engaging with the towline during towing procedure.

Description

Field of the Invention

[0001] The present invention relates to the field of tugboats or tug vessel, comprising a hull and a towing assembly, said towing assembly further comprising a towing staple assembly for a hull of a vessel for towing and a hull for a vessel for towing comprising the towing staple.Background of the Invention

[0002] A vessel for towing, such as a tugboat or tug, is a secondary boat that is used for maneuvering other, typically larger, vessels by pushing or pulling them either by direct contact or by means of a tow line. Tugs typically move vessels that either are restricted in their ability to maneuver on their own, such as ships in a crowded harbor or a narrow canal, or vessels that cannot move by themselves, such as barges, disabled ships, log rafts, or oil platforms.

[0003] Without the help from a more nimble and maneuverable towing vessel, larger ships, such as mega-ships, would not be able to, or at least have difficulties, getting into a port.

[0004] There are different types of tugboats, with different types of propulsion systems and pulling characteristics, such as the conventional tugboat, the tractor tug and the so-called azimuth stern drive tug.

[0005] Tugboats may use their propulsion system and / or hydrodynamic characteristics of the hull to generate forces for maneuvering the towed vessel. Tugboats may operate in a direct towing mode or an indirect towing mode. During direct mode operations a towing force on the towline is produced, due to a pull of the tugboat's propulsion system. Therefore, operations such as stopping or reducing the towed vessel's initial movement, or assisting the towed vessel during steering, is performed by keeping the tugboat either parallel to the vessel's centerline or open to the corresponding side of the towed vessel.

[0006] During indirect towing, which may also be referred to as dynamic towing, the tugboat usually trails the towed vessel and exerts forces on the towed vessel for turning and / or decelerating the towed vessel. The tugboat's propulsion system may be used to place and maintain the hull of the tugboat in an angled position in relation to the towed vessel. Thereby, hydrodynamic forces will be created by the vessel's hull acting against the direction of travel of the towed vessel. By positioning the side, such as a starboard or port side, of the tugboat against the direction of travel of the towed vessel the hull of the tugboat will provide a large surface acting against the flow direction of the water thereby generating drag forces which may be transmitted to the towed vessel for turning and / or decelerating the towed vessel. Decelerating and / or steering is controlled by the tug by maintaining a reference angle corresponding to the water flow direction, as opposed to the direction taken by the towed vessel. The port side is the side of the vessel which is to the left of an observer facing the bow, that is, facing forward towards the direction the vessel is heading when underway, and the starboard side is to the right side of such an observer.

[0007] A tugboat's towing equipment is a crucial link for transferring forces generated by the tugboat to the towed vessel. The towing equipment may comprise various elements which may vary between different types of tugboats. These elements are in the simplest versions just a towing bitt and towline or a towing hook and towline. The towing equipment may however also comprise a towing winch, a fairlead, the towline, and / or towing pins. Each element of the towing equipment must be strong enough or designed in such a way that it can cope with the high forces generated in the towline. Due to the high forces the towline is typically heavy and strong. A failure of any of the elements in the towing equipment may lead to the towline suddenly snapping or sweeping over a deck of the tugboat, which may cause injuries to crew members working on the deck of the tugboat.

[0008] A further crucial aspect is a location of the towing point, wherein the towing point herein shall be interpreted as a point on the tugboat from where the towline applies the forces of the towing procedure on the tugboat. The location of the towing point may vary between different types of tugboats. The location of the towing point and thereby the point where the majority of the tugging forces are applied on the tugboat, has a major influence on the tugboat's properties.

[0009] The danger with towing using a towline is the risk of girting and capsizing. Girting may happen when the towline comes at right-angles to the tugboat, e.g., during indirect towing when the hull of the tugboat is positioned perpendicular to the towed vessel. If the towline is secured around amidships of the tugboat and position at a right angle to the tugboat, then the towline under tension will exert a heeling moment on the tugboat. As with any vessel which heels over to one side, such as the starboard or port side, due to an external force, a righting lever may be formed as a center of buoyancy of the tugboat moves towards a center of the tugboats underwater volume, countering the heeling moment and pushing the tugboat back upright again. However, if the force in the towline is sufficiently powerful, it may overcome the tugboat's righting lever which may lead to deck-edge immersion of water, flooding and capsizing, which may also be referred to as girting, unless the towline is released in good time. Girting may occur very rapidly, and incidents have occurred where crew members have not been able to escape in time.

[0010] WO2011 / 139154 A2 discloses a towing device comprising two propulsion systems arranged along the longitudinal direction of the vessel, where the tow point is arranged between the first and the second propulsion system, for increased stability during indirect pulling, but without disclosing where on the longitudinal line between the two propulsion systems the tow point should be placed or how to achieve a beneficial towing point, for not only increased stability and but also efficiency of the towing device.

[0011] WO2021 / 156252 A1 discloses a hull for a vessel for towing, comprising a towing stable, or a towing structure for guiding a towline, comprising a guiding element having a symmetrical extension in a first plane parallel to the deck, comprising a towline guiding surface facing the deck, such that the towline can freely move along a periphery of the main section of the towing stable in the first plane while being restricted in movement by the main section in a direction perpendicular to the first plane, thereby controlling the vertical movement of the towing forces, by keeping the towing forces closer to the deck of the vessel for increased stability, however, the publication does not consider the effect of the horizontal placement of the towing force or towing point on the stability, nor the effect that the towing point has on the utilization of the propulsion system of the towing vessel and towing efficiency of the towing vessel.

[0012] Accordingly, there is a need for a towing solution, which mitigate, alleviate or address the shortcomings of the existing towing solutions, while providing a reliable and cost-effective solution for towing which reduces the risk of failure while fully utilizing the power of the tug.Object of the Invention

[0013] It is an objective of the present invention to improve the stability and efficiency of the prior art towing vessels / tugboats.

[0014] A further objective of the present invention is to provide a hull for a towing vessel comprising a towing stable constructed to control and optimize the towing points during different towing procedures, that is the location where the towing forces act on the towing vessel / tugboat during both direct, semi-direct and indirect towing procedure.

[0015] A further objective of the present invention is to provide a hull for a towing vessel comprising a towing stable constructed to control and optimize where the towing forces act on the towing vessel / tugboat during both direct and semi-direct towing procedure, thereby ensuring that the towing point is in close proximity to the longitudinal axis of the vessel for less interference between the forward propulsion system and the reward propulsion system, and full utilization of the force of both propulsion systems.

[0016] A further objective of the present invention is to provide a hull for a towing vessel comprising a towing stable constructed to control and optimize where the towing forces act on the towing vessel / tugboat during indirect towing, ensuring that during indirect towing, the towing point is such that the towing forces applied through the at least one towline on the hull rotates the towing vessel, such that the angle between the central longitudinal axis (A) of the hull and the at least one towline is not 90 degrees, thereby ensuring safe failure mode.Description of the Invention

[0017] One objective of the invention is achieved by providing a hull for a vessel for towing, comprising a deck; a forward propulsion system and a reward propulsion system, the two propulsion systems aligned along the central longitudinal axis of the hull; at least one winch comprising at least one towline; and a towing staple for guiding the at least one towline, wherein the towing staple comprises: two outer towline stoppers, mounted to the hull; a support element comprising a forward mounting section mounted to the hull and a rearward mounting section mounted to the hull, the rearward mounting section comprising a guiding element mounted to the hull by means of the two outer towline stoppers, the guiding element extending between the two outer towline stoppers in a first plane substantially parallel to the deck arranged for allowing the towline to move freely along the periphery of the guiding element between the two outer towline stoppers; and one or more inner towline stopper, mounted to the hull arranged laterally amidships, centrally on or in close proximity to the longitudinal axis of the hull, the at least one inner towline stopper arranged for engaging with the at least one towline extending from the at least one winch towards the guiding element and / or one of the two outer towline stoppers; wherein one or more inner towline stopper is arranged on and / or in close proximity to the central crosswise axis of the hull.

[0018] Accordingly, it is one object of the present invention to provide a vessel for towing, wherein the at least one inner towline stopper is arranged as the towing point of the towing vessel when the at least one towline exits the vessel in the periphery of the guiding element, thereby ensuring that the towing point is in close proximity to the longitudinal axis of the vessel for less interference between the forward propulsion system and the reward propulsion system, and full utilization of the force of both propulsion systems.

[0019] Accordingly, it is another object of the present invention to provide a method of using hull according to the invention for bollard pull, wherein one of the outer towline stoppers is arranged as the towing point of the towing vessel, ensuring that during bollard pull, the pulling forces applied through the at least one towline on the hull rotates the towing vessel, such that the angle between the central longitudinal axis (A) of the hull and the at least one towline is not 90 degrees, thereby ensuring safe failure mode.

[0020] The hull for a vessel for towing provided by the present invention thereby provides a towing stable wherein the one or more inner towline stoppers or one of the two outer towline stoppers are arranged as construct the location where the main towing forces are applied on the towing vessel during towing, that is the towing point of the tugboat.

[0021] The towing stable provided by the present invention, thus constructs a towing point between the two propulsion systems by utilizing the arrangement of the towline stoppers. It is highly beneficial for both the stability and efficiency of the towing vessel to arrange the towing point in close proximity to the central crosswise axis of the hull, as such arrangement results in less interference between the two propulsion systems, as the arrangement of the towline stoppers and thereby the towing point results in the towing vessel automatically arranging itself at an angle, such that interference between the two propulsion system is minimized.

[0022] Another advantageous effect of the arrangement of the towline stoppers and thereby the towing point between the two propulsion systems, in close proximity to the central crosswise axis of the hull of the towing vessel, is that the towing vessel will have better navigation ability and improved manoeuvring properties during a towing procedure.

[0023] Yet another highly beneficial effect of the arrangement of the towline stoppers and thereby the towing point between the two propulsion systems, in close proximity to the central crosswise axis of the hull of the towing vessel, is that such arrangement of the towing point considerably increases the righting movement / moment or stability of the towing vessel moment, especially during indirect high-speed towing procedure, wherein the towline will extend upward from the towing vessel and the arrangement of the towing point, between the two propulsion systems, in close proximity to the central crosswise axis of the hull of the towing vessel will increase the righting movement / moment capabilities of the vessel, thereby correcting or counteracting any cap-sizing.

[0024] Yet another advantageous effect of the arrangement of the towline stoppers and thereby the towing point between the two propulsion systems, in close proximity to the central crosswise axis of the hull of the towing vessel is improved equilibrium position, that is the position that the towing vessel returns to or seeks during shut down, failure of towline or save failure, that is during disruption of towing procedure. The equilibrium position is the position that the towing vessel seeks or wants, and is also the staring position, when the towing vessel is running or driving at low speed / engine power. The equilibrium position is the position that the towing vessel will return to or align to, during failure, such as snapping of the towline and / or engine failure.

[0025] Another advantageous effect of the arrangement of the towline stoppers and thereby the towing point between the two propulsion systems, in close proximity to the central crosswise axis of the hull of the towing vessel, is that the arrangement of the towline stoppers constructs different towing points during different towing procedures. During indirect towing, the towline engages with one of the outer towline stoppers, thereby constructing a towing point at the location of the outer towing stopper that engages with the towline. During direct towing, the towline does not engage with any of the two outer towline stoppers, and therefore the towing point is at the location of the one or more inner towline stopper, that does engage the towline.

[0026] Yet another highly beneficial effect of the arrangement of the towline stoppers and thereby the towing point between the two propulsion systems, in close proximity to the central crosswise axis of the hull of the towing vessel is the combination of different advantages, resulting in a towing vessel with superior properties, both during pulling or pushing.

[0027] In one embodiment of the present invention, a vessel for towing is provided comprising a towing stable wherein one or more inner towline stopper is arranged closer to the central crosswise axis (B) of the hull than the reward propulsion system. In another embodiment of the present invention, a vessel for towing is provided comprising a hull with a longitudinal length (L) and a towing stable comprising one or more inner towline wherein the one or more inner towline stopper is arranged such that the distance between one or more inner towline stopper and the central crosswise axis (B) of the hull is 25% or less, such as 12.5% or less of the longitudinal length (L) of the hull.

[0028] In one embodiment of the present invention, a vessel for towing is provided comprising a towing stable wherein the two outer towline stoppers are arranged closer to the central crosswise axis (B) of the hull than the reward propulsion system. In another embodiment of the present invention, a vessel for towing is provided comprising a hull with a longitudinal length (L) and a towing stable comprising two outer towline stoppers, wherein the two outer towline stoppers are arranged such that the distance between any of the two outer towline stoppers and the central crosswise axis (B) of the hull is 25% or less, such as 12.5% or less of the longitudinal length (L) of the hull.

[0029] In one embodiment of the present invention, a vessel for towing is provided comprising a hull a with longitudinal length (L), the hull comprising a towing stable comprising one or more inner towline stopper and two outer towline stoppers, wherein the longitudinal length (L) of the hull is divided into two equal halves each spanning 50 percent of the longitudinal length (L) of the hull and wherein the one or more inner towline stopper and the two outer towline stoppers are arranged within the first half or 50% of the longitudinal length (L) of the hull from the central crosswise axis (B).

[0030] In another embodiment of the present invention, a vessel for towing is provided comprising a hull a with longitudinal length (L), comprising a towing stable comprising one or more inner towline stopper and two outer towline stoppers, wherein the longitudinal length (L) of the hull is divided into four equal lengths, each spanning one-fourth or 25% or 25 percent of the total longitudinal length (L) of the hull and wherein the one or more inner towline stopper is arranged within the first one-fourth that is 25% or 25 percent of the total longitudinal length (L) of the hull from the central crosswise axis (B), and in yet another embodiment of the present invention, the one or more inner towline stopper and the two outer towline stoppers are arranged within the first one-fourth that is 25% or 25 percent of the total longitudinal length (L) of the hull from the central crosswise axis (B).

[0031] In another embodiment of the present invention, a vessel for towing is provided comprising a hull a with longitudinal length (L), comprising a towing stable comprising one or more inner towline stopper and two outer towline stoppers, wherein the longitudinal length (L) of the hull is divided into eight equal lengths, each spanning one-eight or 12.5% or 12.5 percent of the total longitudinal length (L) of the hull and wherein the one or more inner towline stopper is arranged within the first one-eight or 12.5% or 12.5 percent of the total longitudinal length (L) of the hull from the central crosswise axis (B), in yet another embodiment of the present invention, the one or more inner towline stopper and the two outer towline stoppers are arranged within the first one-eight or 12.5% or 12.5 percent of the total longitudinal length (L) of the hull from the central crosswise axis (B).

[0032] In another embodiment of the present invention, a vessel for towing is provided comprising a hull a with longitudinal length (L), comprising a towing stable comprising one or more inner towline stopper and / or two outer towline stoppers, wherein the one or more inner towline stopper and / or the two outer towline stoppers are arranged at a distance (D) rearwardly between the central crosswise axis (B) of the hull and the stern of the hull, and wherein the distance (D) between the central crosswise axis (B) and the one or more inner towline stopper and / or the two outer towline stoppers is less than the distance between the stern and the one or more inner towline stopper and / or the two outer towline stoppers. In one embodiment the distance (D) between the central crosswise axis (B) and the one or more inner towline stopper and / or the two outer towline stoppers is equal to or less than the half or 50% of the distance between the stern and the central crosswise axis (B), such as 40%, 30%, 25%, 20%, 15%, 12% of the distance between the stern and the central crosswise axis (B).

[0033] In one embodiment of the present invention, a vessel for towing is provided comprising a hull, the hull comprising a towing stable comprising an innermost inner towline stopper and two outermost inner towline stoppers. In another embodiment of the present invention, a vessel for towing is provided comprising a hull, the hull comprising an innermost inner towline stopper and two outermost inner towline stoppers wherein the innermost inner towline stopper is arranged on the longitudinal axis (A) of the hull between the winch and the two outermost inner towline stoppers, and wherein the innermost inner towline stopper is arranged as to engage the at least one towline extending from the at least one winch, and constructing a towing point at the location of the innermost inner towline stopper. In another embodiment of the present invention, a vessel for towing is provided comprising a hull, the hull comprising a towing stable comprising an innermost inner towline stopper and two outermost inner towline stoppers wherein the innermost inner towline stopper is arranged on the longitudinal axis (A) of the hull between the winch and the two outermost inner towline stoppers, and wherein the two outermost inner towline stoppers are arranged rearwardly from the innermost inner towline stopper, between the innermost inner towline stopper and the stern of the hull. In one embodiment of the present invention, a vessel for towing is provided comprising a hull, the hull comprising a towing stable comprising an innermost inner towline stopper and two outermost inner towline stoppers wherein the innermost inner towline stopper is arranged on the longitudinal axis (A) of the hull between the winch and the two outermost inner towline stoppers, and wherein the two outermost inner towline stoppers are arranged rearwardly from the innermost inner towline stopper, between the innermost inner towline stopper and the guiding element and are arranged to engage the least one towline extending from the innermost inner towline stopper towards the outer towline stoppers and / or the guiding element (20).

[0034] In another embodiment of the present invention, a vessel for towing is provided comprising a hull a with longitudinal length (L), the hull comprising a towing stable comprising an innermost inner towline stopper and two outermost inner towline stoppers and wherein the innermost inner towline stopper and the two outermost inner towline stoppers are arranged at a distance (D) rearwardly between the central crosswise axis (B) of the hull and the stern of the hull, and wherein the distance (D) between the central crosswise axis (B) and the one or more inner towline stopper and / or the two outer towline stoppers is less than the distance between the stern and the central crosswise axis (B), such equal to or less than the half or 50% of the distance between the stern and the central crosswise axis (B), such as 40%, 30%, 25%, 20%, 15%, 12% of the distance between the stern and the central crosswise axis (B).

[0035] In another embodiment of the present invention, a vessel for towing is provided comprising a hull a with longitudinal length (L), the hull comprising a towing stable comprising an innermost inner towline stopper and two outermost inner towline stoppers and wherein the innermost inner towline stopper and the two outermost inner towline stoppers are arranged on and / or in close proximity to the central crosswise axis (B) of the hull. In yet another embodiment of the present invention, a vessel for towing is provided comprising a hull a with longitudinal length (L), the hull comprising a towing stable comprising an innermost inner towline stopper and two outermost inner towline stoppers, the three inner towline stoppers arranged such that the distance between anyone of the three inner towline stoppers and the central crosswise axis (B) of the hull is 25% or less of the longitudinal length (L) of the hull, such as 20% or less, such as 15% or less, such as 12% or less or such as 10% or less of less of the longitudinal length (L) of the hull.

[0036] In one embodiment of the present invention, a vessel for towing is provided comprising a hull, the hull comprising a towing stable comprising at least one tow pin, mounted to the hull, wherein the at least one tow pin is arranged for being reversibly displaceable between a retracted position and engaging position where the tow pin engages with the guiding element of the arranged for engaging with the guiding element (20), thereby creating a reversible physical obstruction for the movement of the towline (10) along the guiding element. In one embodiment of the present invention a vessel for towing is provided comprising a hull, the hull comprising a towing stable comprising at least one tow pin, mounted to the hull, wherein the at least one tow pin is arranged for being reversibly displaceable between a retracted position and engaging position where the tow pin engages with the guiding element of the arranged for engaging with the guiding element, thereby creating a reversible physical obstruction for the movement of the towline along the guiding element, and wherein the tow pin is arranged directly above the rearward propulsion system.

[0037] In one embodiment of the present invention, a vessel for towing is provided comprising a hull, the hull comprising a towing stable comprising at least one tow pin mounted to the hull by a tow pin mounting stable, wherein the tow pin mounting stable comprises a upper surface arranged for supporting the towline when one or more tow pins are arranged in engaging position, such that a closed guiding surface is constructed by the one or more tow pin, the surface of the guiding element and the upper surface of the tow pin mounting stable.

[0038] In one embodiment of the present invention, the towline is locked between two tow pins, the surface of the guiding element between the two tow pins and the upper surface of the tow pin mounting stable during direct towing, thereby creating a towing point at the location of the tow pins. In one embodiment of the present invention the towing pins are placed on the central longitudinal axis of the towing vessel, directly above the rearward propulsion system, thereby directing the towing forces directly at the location of the rearward propulsion system for better utilization of the propulsion forces and more stability of the towing vessel during direct towing procedure.

[0039] The vessel for towing provided by the present invention comprises a towing stable, wherein the arrangement of the outer towline stoppers constructs the towing point during indirect towing procedure. The arrangement of the outer towline stoppers and the engagement of outer towline stoppers with the towline during indirect towing, results in the towing point being at the outer towline stopper engaging with the towline, and the present invention provides a towing vessel comprising a towing stable wherein the position of the outer towline stoppers is optimized such that the towing point during the indirect towing is optimal for the stability of the towing vessel, while simultaneously constructing a save failure mode by improving the equilibrium position of the towing vessel.

[0040] The vessel for towing provided by the present invention comprises a towing stable, comprising a guiding element mounted to the hull by means of the two outer towline stoppers, the guiding element extending between the two outer towline stoppers in a first plane substantially parallel to the deck arranged for allowing the towline to move freely along the periphery of the guiding element between the two outer towline stoppers. Ine one embodiment of the present invention, the towing point during towing procedure is the location of the inner towline stopper engaging with the towline, if and when the towline exits the towing vessel at the periphery of the guiding element, without engaging with either of the two outer towline stoppers, in another embodiment of the present invention, the towing point during towing procedure is the point of engagement between the innermost inner towline stopper and the towline if and when the towline exits the towing vessel at the periphery of the guiding element.

[0041] The vessel for towing provided by the present invention comprises a towing stable, wherein the arrangement of the one or more inner towline stopper and the two outer towline stoppers ensures that during the indirect towing procedure, the pulling forces applied through the at least one towline on the hull rotates the hull, such that the angle (C) between the central longitudinal axis (A) of the hull and the at least one towline is not 90 degrees.

[0042] Yet another advantageous effect of the arrangement of the towline stoppers and thereby the towing point between the two propulsion systems, in close proximity to the central crosswise axis of the hull of the towing vessel is improved equilibrium position, that is the position that the towing vessel returns to or seeks during shut down, failure of towline or save failure, that is during disruption of towing procedure. The equilibrium position is the position that the towing vessel seeks or wants, and is also the staring position, when the towing vessel is running or driving at low speed / engine power. The equilibrium position is the position that the towing vessel will return to or align to, during failure, such as snapping of the towline and / or engine failure.Definitions: Towing vessel / tugboat:

[0043] The phrases "towing vessel", "tugboat" or "a tug" are used interchangeably within this application, and refer to a boat or a vessel, that is designed for and applied as an assistance boat which helps in the mooring or berthing operation of a ship by either towing or pushing a vessel towards the port.

[0044] A "towing vessel", "tugboat" or "a tug" is a particular class of boat which helps mega-ships enter or leave a port. In addition to towing the vessel towards the harbour, tugboats can also be engaged to provide essentials, such as water, air, etc., to a vessel.

[0045] The propulsion system of a "towing vessel", "tugboat" or "a tug" is the main reason behind their strength, and together with their solid structural engineering, tugs are small but relatively powerful machines, with tonnage ratio ranging between 2.20-4.50 for large tugs and 4.0-9.5 for harbor tugs. These are incredibly high ratios, especially considering the ratio of cargo ships or vessels varies between 0.35 and 1.20.

[0046] Since "towing vessel", "tugboat" or "a tug" maneuverability is one of its assets, it is important to maintain maneuverability while increasing the strength and power of the propulsion system and even more importantly increasing the utilization of the power of the tugboat by improving the tugboats stability during full power pull and / or high-speed pulling.Rearward / rearwards:

[0047] The phrases "reward / s, back, backward / s or rear-end" as used within this application, is to be understood in the content of this disclosure as being utilized in relation to the towing vessel and the towing vessels sailing direction, thus referring to the direction towards the stern of the towing vessel.Forward / forwards:

[0048] The phrases forward / s or front, as used within this application, is to be understood in the content of this disclosure as being utilized in relation to the towing vessel and its sailing direction, thus referring to the bow of the towing vessel.In close proximity to:

[0049] The phrase "in close proximity to" or close to, as used within this application, is to be understood in the content of this disclosure as being closer to one point than another. This can be in a situation where there is a line or distance that can be divided in two, by a midpoint, and then an object or point "in close proximity to" the midpoint, would mean that said object / point is closer to the midpoint than to either endpoint.Towing point

[0050] The phrase "towing point" as used within this application, is to be understood in the content of this disclosure as the location or point on the hull of the towing vessel, where, during towing procedure, the towing line applies the forces of the towing procedure on the tugboat. This means that the phrase "towing point" as used within this application refers to the location receiving majority of the towing forces during towing procedure. The towing point may vary between different types of tugboats, and the location of the towing point and thereby the point where the majority of the tugging forces are applied on the tugboat, has a major influence on the performance, characteristics and performance of a towing vessel or tugboat during towing procedure.Save failure mode:

[0051] The phrase "save failure mode" as used within this application, is to be understood in the content of this disclosure as a safety feature that allows the captain / crew of the tugboat / towing vessel to react in a save manner to a pending risk of the towing vessel girting and capsizing, such that an abrupt halt to the towing procedure will not result in any hazardous events, such as un-stabilizing forces on the towing vessel, any sudden movement of the towing vessel, snapping or abrupt movement of the towline or other risks for the stability of the towing vessel and / or the health of the crew.Propulsion system interaction:

[0052] The phrases "propulsion systems interaction" or "thruster-to-thruster interaction" as used within this application, are to be understood in the content of this disclosure, as the possible interaction or interference of the waterflow from one of the two propulsion system on the other propulsion system. As the present invention provides a vessel for towing with a forward propulsion system and a reward propulsion system arranged along the longitudinal direction of the towing vessel, there are situations or positions of the towing vessel, wherein the flow of the water from one of the propulsion device / system can be directed at the other propulsion device / system, thereby creating an interference that decreases the utilization of the power of the propulsion systems and thereby the efficiency of the towing vessel.Direct towing:

[0053] The phrase "direct towing" used within this application, is commonly understood within the field, as a method of towing, where the towing vessel is attached to the bigger ship by a towline, the tugboat moving forward while utilizing the towline for towing or dragging the bigger ship directly behind and wherein the towline is exiting the towing vessel / tugboat along the central longitudinal axis A of the tugboat.Indirect towing:

[0054] The phrase "indirect towing" used within this application, is understood within this disclosure as a method of towing, where the towing vessel is attached to the bigger ship by a towline, and where due to the circumstances, such as lack of space for manoeuvring the tugboat / towing vessel, the tugboat is towing the bigger ship at an angle, such that the towing line is directly engaging with one of the outer towline stoppers, and the location of the outer towline stopper directly engaging with the towline is the towing point during such towing procedure.Semi-direct towing:

[0055] The phrase "semi-direct towing" used within this application, is understood within this disclosure as a method of towing, where the towing vessel is attached to the bigger ship by a towline, and where the tugboat is towing the bigger ship at an angle that lies between the angle created during indirect-towing and the direct towing, such that the towing line is not lined up to the central longitudinal axis A of the tugboat as during direct towing, but not exiting the tugboat by interacting directly with one of the outer towline stopper, but exiting the tugboat along the vessel in the periphery of the guiding element between the central longitudinal axis A of the tugboat and the two outer towline stoppers.Description of the Drawing

[0056] Various examples are described hereinafter with reference to the figures. Like reference numerals refer to like elements throughout. Like elements will, thus, not be described in detail with respect to the description of each figure. It should also be noted that the figures are only intended to facilitate the description of the examples. They are not intended as an exhaustive description of the claimed invention or as a limitation on the scope of the claimed invention. In addition, an illustrated example need not have all the aspects or advantages shown. An aspect or an advantage described in conjunction with a particular example is not necessarily limited to that example and can be practiced in any other examples even if not so illustrated, or if not so explicitly described.

[0057] Exemplary embodiments of the invention are described in the figures, whereon: Fig. 1Aillustrates a side view of an embodiment of a tugboat with a towing stable according to the present invention. Fig. 1Billustrates a side view of another embodiment of a tugboat with a towing stable according to the present invention. Fig. 2illustrates a top-down view of an embodiment of a towing stable on a tugboat according to the present invention. Fig 3.illustrates a side view of an embodiment of a towing stable on a tugboat according to the present invention. Fig. 4illustrates a front view of an embodiment of a towing stable on a tugboat according to the present invention. Fig. 5illustrates a partly front view, partly side view of an embodiment of a tugboat with a towing stable according to the present invention. Fig. 6illustrates a top view of an embodiment of a tugboat with a towing stable according to the present invention. Fig. 7illustrates a partly front view, partly side view of an embodiment of a towing stable on a tugboat according to the present invention. Fig. 8aillustrates the position of a towing vessel, comprising a towing stable according to an embodiment of the present invention during indirect towing procedure. Fig. 8billustrates the rotation achieved by a towing vessel, comprising a towing stable according to an embodiment of the present invention during indirect towing procedure. Fig. 9illustrates a top view of an embodiment of a tugboat with a towing stable according to the present invention, demonstrating the length of the tugboat. Detailed Description of the Invention

[0058] Exemplary examples will now be described more fully hereinafter with reference to the accompanying drawings. In this regard, the present examples may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the examples are merely described below, by referring to the figures, to explain aspects.

[0059] Throughout the specification, when an element is referred to as being "connected" to another element, the element is "directly connected" to the other element, "electrically connected", "fluidic connected" or "communicatively connected" to the other element with one or more intervening elements interposed there between.

[0060] The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting. As used herein, the terms "comprises" "comprising" "includes" and / or "including" when used in this specification specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0061] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined in the present specification.

[0062] Fig. 1A and Fig. 1B demonstrate embodiments of a hull (1) for a vessel for towing, such as a tugboat provided by the present invention. The hull (1) of the tugboat comprises a deck (13), such as a main deck of the vessel and ad a towing stable (14) for guiding one or more towing lines (10) (not shown). The deck (13) may be a first deck arranged above a waterline of the hull. There can be one towing line (10) or multiple towing lines (10), the one or more towing line (10) may be towing lines arranged on the hull (1) or / and may be towing lines (10) arranged on a towed vessel. When the one or more towing line (10) is arranged on the hull (1) it may be connected to one or more winch (12) that is mounted to the hull (1). There can be one winch (12) or more than one winch (12), arranged for allowing one or more towing lines (10) to be extended and retracted by being wound up or unwounded from the one or more winch (12).

[0063] The one or more winches (12) are preferably arranged laterally amidships, such as centered on longitudinal axis A of the hull extending from the bow to the stern in the center of the hull (1) (axis A is not shown in Fig. 1, but demonstrated in Fig 2, 4, 6-9) or in close proximity of the longitudinal axis A, depending on the number of winches (12) and the available space for mounting the one or more winches to the hull (1).

[0064] The hull (1) for a vessel for towing, such as a tugboat further comprises two propulsion systems aligned along the central longitudinal axis A of the hull (1), a forward propulsion system (25A) arranged at the forward of the hull (1) and a reward propulsion system (25B) arranged at the rearward of the hull (1), the two propulsion systems separated by the distance D along the central longitudinal axis A. The two propulsion systems may be any suitable propulsion systems known in the art, such as one or more omni-directional propulsion devices, azimuth thrusters, single-screw or twin-screw fixed propellers, Voith-Schneider propellers or any other suitable propulsion devices.

[0065] The embodiments of the present invention demonstrated in Fig. 1A and 1B both provide a vessel for towing, such as a tugboat, wherein the hull (1) is provided with at least one keel (26), in order to increase lateral resistance and towline forces of the vessel in transverse direction under influence of a towing load and to improve course stability of the vessel.

[0066] The embodiments of the present invention demonstrated in Fig. 1A and 1B provide a vessel for towing, such as a tugboat, comprising a towing stable (14), wherein the towing stable (14) comprises a support element (17), the support element (17) comprising a forward mounting section (22) and a rearward mounting section (21), the forward mounting section (22) extending forwards towards the bow of the hull (1). The forward mounting section (22) is mounted to the hull (1), by being mounted to the bridge or wheelhouse (23) of the hull (1) as demonstrated in Fig. 1A, or by being arranged as an integrated part of the bridge (23) as demonstrated in Fig. 1B, or the forward mounting section (22) may be mounted to the hull (1) by any suitable means, such as any mixture of the above mentioned embodiments, such that the forward mounting section (22) is partly attached, partly integrated with the bridge or wheelhouse (23). The rearward mounting section (21) of the support element (17) is mounted to the hull (1) by means of two outer towline stoppers (15A, 15B), the rearward mounting section (21) extending between the two outer towline stoppers (15A, 15B) and the segment of the rearward mounting section (21) that extends between the two outer towline stoppers (15A, 15B) comprising a guiding element (20), the guiding element (20) extending between the two outer towline stoppers (15A, 15B) in a first plane substantially parallel to the deck (13) and wherein the two outer towline stoppers (15A, 15B) and the guiding element (20) together construct a guiding surface (23) constructed for allowing the one or more towline (10) to move freely along the periphery of the guiding element (20) between the two outer towline stoppers (15A, 15B).

[0067] The support element (17) of the towing stable (14) of the embodiments of the present invention demonstrated in Fig. 1A and 1B further comprises an additional mounting element (18), mounted to the hull (1) between the forward mounting section (22) and the rearward mounting section (21).

[0068] The towing stable (14) of the embodiments of the present invention demonstrated in Fig. 1A and 1B further comprises one or more inner towline stopper (16) mounted to the hull (1), arranged for receiving one or more towline (10) (not shown in Fig. 1A or 1B) from the one or more winch (12) and arranged for engaging with the one or more towlines (10) such that the pulling forces applied on the towing vessel, through the towline, when the towline exits the towing vessel anywhere along the periphery of the guiding element, are applied on the one or more inner towline stopper (16), such that the one or more towline stopper (16) defines the position of the towing point of the towing vessel provided by the present invention, during towing procedure where the towing line (10) exits the hull (1) along the periphery of the guiding element (20). As demonstrated in Fig. 1A and 1B, the towing stable (14) of the embodiments of the present invention demonstrated comprises more than one inner towline stopper (16).

[0069] The towing stable (14) of the embodiments of the present invention shown in Fig. 1A and 1B further comprises one or two tow pins (27) mounted to the hull (1), arranged as to be reversibly displaceable between a retracted position and engaging position, such that when the one or two tow pins (27) are in an engaging position, one or more of the tow pins engages with the guiding element (21) of the towing stable (14), thereby creating a reversible physical obstruction for the movement of the towline (10) along the periphery of the guiding element (20). The tow pins (27) of the embodiments shown in Fig. 1A and 1B are mounted to the hull directly above the rearward propulsion system (25B), for additional stability of the towing vessel during direct towing, that is when the towline (10) is locked by the tow pins (27), whereby the towing point is placed directly above the rearward propulsion system (25B), resulting in more efficiency of the towing vessel by improved utilization of the propulsion system during direct towing.

[0070] Fig. 2 illustrates a top-down view of a rear end of a vessel for towing, such as a tugboat, comprising an embodiment of a towing stable (14) according to the present invention. The towing stable (14) is mounted to the deck (13) of the hull (1) and comprises a support element (17) comprising additional mounting elements (18) mounting the support element to the hull (1), between the rearward mounting section (21) and the forward mounting section (22), where in the embodiment disclosed in Fig. 2, the additional elements (18) are constructed as two pairs of additional elements on each side of the hull (1). The rearward mounting section (21) is mounted to the deck (13) of the hull (1) by means of an outer towline stopper (15A) on one side of the hull (1) and by means of an outer towline stopper (15B) on the other side of the hull (1). The rearward mounting section (21) comprises a guiding element (20) extending between the two outer towline stoppers (15A, 15B), in a first plane substantially parallel to the deck (13), the guiding element (20) constructed for allowing the one or more towline (10) to move freely along the periphery of the guiding element (20) between the two outer towline stoppers (15A, 15B).

[0071] The rearward mounting section (21) of the embodiment of a towing stable (14) according to the present invention extends between the two outer towline stoppers (15A, 15B) in a semi-oval shape, such that the guiding element (20) stretches somewhat along the central longitudinal axis (A) between the outer towline stoppers, but does not follow the curvature of the gunwale (2) as shown in Fig. 2, such that the distance between the guiding element (20) and the gunwale (29) is not constant along the periphery of the guiding element (20).

[0072] The towing stable (14) of the embodiment shown in Fig. 2, further comprises three winches (12) mounted to the hull (1), and three inner towline stoppers (16) mounted to the hull, the winches (12) arranged laterally amidships, that is the winches are arranged centrally on or close to the longitudinal axis A of the hull extending from the bow to the stern along the longitudinal center of the hull (1). The three inner towline stoppers (16A, 16B, 16B') of the embodiment demonstrated in Fig. 2 are arranged as to construct a triangle, with the innermost inner towline stopper (16A) mounted to the hull between the three winches and the two outermost inner towline stoppers (16B, 16B'), the innermost inner towline stopper (16A) arranged centrally on or very close to the longitudinal axis A of the hull, while the two outermost inner towline stoppers (16B, 16B') are mounted to the hull (1) rearwards from the three winches and the innermost inner towline stopper (16A), with a longer distance from the central longitudinal axis A than the innermost inner towline stopper (16A) and are arranged symmetrically with the same distance from both the central longitudinal axis A and the innermost towline stopper (16A).

[0073] In the embodiment of the present invention, shown in Fig. 2, the towing line (10) is arranged for being extended and retracted by being wound up or unwounded from the middle winch of Fig 2 and extends from the middle winch towards to the innermost inner towline stopper (16A) and engages with the innermost inner towline stopper (16A) before extending to and engaging with the outer towline stopper (15B), that is the towing stable demonstrated in Fig. 2 is shown during indirect towing procedure, wherein the towline (10) engages directly with the outer towline stopper (15B) and thereby ensures that the towing forces are applied at the location of the outer towline stopper (15B) wherein the location of the outer towline stopper (15B) becomes the towing point during the indirect towing procedure. This arrangement and engagement of the outer towline stopper (15B), results in the towing point being at the outer towline stopper (15B), the position of the outer towline stopper (15B) being optimized such that the towing point during the indirect towing is optimal both for the stability of the towing vessel considerably, and creating a save failure mode, wherein the towing point of the towing vessel is located such that during towing procedure, it is possible for the captain / crew of the tugboat / towing vessel to react in a save manner to a pending risk of the towing vessel girting and capsizing, such that an abrupt halt to the towing procedure will not result in any hazardous events, such as un-stabilizing forces on the towing vessel, any sudden movement of the towing vessel, snapping or abrupt movement of the towline or other risks for the stability of the towing vessel and / or the health of the crew.

[0074] The towing stable (14) of the embodiment of the present invention shown in Fig. 2 further comprises one or two tow pins (27) mounted to the hull (1) by a tow pin mounting stable (28), the one or two tow pins (27) arranged as to be reversibly displaceable between a retracted position and engaging position, such that when the one or two tow pins (27) are in an engaging position, one or more of the tow pins engages with the guiding element (21) of the towing stable (14), thereby creating a reversible physical obstruction for the movement of the towline (10) along the guiding element (20). In the embodiment illustrated in Fig. 2, the one or more tow pins (27) are placed centrally on the longitudinal axis A of the hull (1).

[0075] Fig. 3 illustrates a side view of an embodiment of a towing stable (14) according to the present invention, on a vessel for towing, such as a tugboat, the towing stable comprising a support element (17) comprising a forward mounting section (2) mounted to the bridge (23) and a rearward mounting section (21), the rearward mounting section (21) comprising a guiding element (20), (the mounting of the rearward mounting section (21) to the hull (1) is not demonstrated in Fig. 3), the support element (17) further mounted to the hull (1) between the forward (22) and the rearward (21) mounting sections by an additional mounting element (18). The towing stable (14) of the embodiment of the present invention shown in Fig. 3 further comprises at least one winch (12) and three inner towline stoppers (16A, 16B, 16B'), arranged and mounted to the hull (1) between the rearward mounting section (21) and the at least one winch (12), wherein the innermost inner towline stopper (16A) is arranged as to be closest to the winch (12) for receiving and engaging one or more towline (10) from the winch (12), and the two outermost inner towline stoppers (16B, 16B') are arranged as to receive and engage the one or more towline extending from the innermost inner towline stopper (16A). In the embodiment of the present invention shown in Fig. 3, the innermost inner towline stopper (16A) is coupled with one or both of the outermost inner towline stoppers (16B, 16B') with a coupling (19).

[0076] The towing stable (14) of the embodiment of the present invention shown in Fig. 3 further comprises one or more tow pins (27) mounted to the hull (1) by a tow pin mounting stable (28), the tow pin mounting stable (28) having a upper surface arranged for supporting the towline when one or more tow pins (27) is arranged in engaging position, such that a closed guiding surface is constructed by the one or more tow pin (27), the surface of the guiding element (20) and the upper surface of the tow pin mounting stable (28).

[0077] In one embodiment of the present invention, the towline is locked between two tow pins, the surface of the guiding element (20) between the two tow pins and the upper surface of the tow pin mounting stable during direct towing, thereby creating a towing point at the location of the tow pins. In one embodiment of the present invention the towing pins are placed on the central longitudinal axis of the towing vessel, directly above the rearward propulsion system, thereby directing the towing forces directly at the location of the rearward propulsion system for better utilization of the propulsion forces and more stability of the towing vessel during direct towing procedure.

[0078] Fig. 4 illustrates a front view of an embodiment of a towing stable (14) according to the present invention, on a vessel for towing, such as a tugboat, the towing stable comprising a support element (17) arranged as to span majority of the width of the deck (13), the support element (17) comprising a rearward mounting section (21) comprising a guiding element (20), the rearward mounting section (21) mounted to the hull (1) with two outer towline stoppers (15A, 15B), close to the gunwale (29). The towing stable (14) of the embodiment of the present invention shown in Fig. 4 further comprises three inner towline stoppers (16A, 16B, 16B'), the innermost inner towline stopper (16A) arranged on the central longitudinal axis (A) at the center of the hull (1) and coupled to the two outermost inner towline stoppers (16B, 16B') with a coupling (19), the two outermost inner towline stoppers (16B, 16B') arranged more rearwardly (closer to the viewpoint of Fig. 4) than the innermost inner towline stopper (16A), the two outermost inner towline stoppers (16B, 16B') arranged symmetrically, with the same distance from both the innermost inner towline stopper (16A) and the same distance from the central longitudinal axis (A) as to construct a triangle.

[0079] Fig. 5 illustrates a partly front view, partly side view of a vessel for towing, such as a tugboat, comprising a towing stable (14) according to one embodiment of the present invention. The tugboat illustrated in Fig. 5 comprises a hull (1) comprising a bridge (23), a forward propulsion system (25A) and a rearward propulsion system (25B), the two propulsion systems aligned along the central longitudinal axis (A) of the hull (1) and a keel (26) arranged along the central longitudinal axis (A) of the hull (1) between the two propulsion systems (25A, 25B). The towing stable (14) of the embodiment of the present invention shown in Fig. 5 comprises a support element (17) comprising a forward mounting section (22) and a rearward mounting section (21), the forward mounting section (22) extending forwards from an additional mounting element (18) mounted to the hull (1) and mounted to the bridge (23) of the hull (1) and the rearward mounting section (21) extending rearwards from the additional mounting element (18), the rearward mounting section (21) being arranged to be mounted to the hull by two outer towline stoppers (15A, 15B), the rearward mounting section (21) comprising a guiding element (20) extending between the two outer towline stoppers (15A, 15B) (only one shown in Fig. 5) in a first plane substantially parallel to the deck (13). The towing stable (14) of the embodiment of the present invention shown in Fig. 5 further comprises one or two tow pins (27) mounted to the hull (1), arranged as to be reversibly displaceable between a retracted position and engaging position, such that when the one or two tow pins (27) are in an engaging position, one or more of the tow pins engages with the rearmost part of the guiding element (21) of the towing stable (14), thereby creating a reversible physical obstruction for the movement of the towline (10) along the guiding surface (24). In the embodiment illustrated in Fig. 5, the one or more tow pins (27) are placed centrally on the longitudinal axis A of the hull, or the directly above the reward propulsion system (25B) and directly under the rearmost part of the guiding element (20) of the rearward mounting section (21) of the towing stable (14).

[0080] Fig. 6 illustrates a top view of a vessel for towing, such as a tugboat, comprising a towing stable (14) according to one embodiment of the present invention. The tugboat shown in Fig. 6 comprises a hull (1) comprising a bridge (23), a deck (13), a gunwale (29), a forward propulsion system (25A) and a rearward propulsion system (25B), the two propulsion systems aligned along the central longitudinal axis (A) of the hull (1). The towing stable (14) of the embodiment of the present invention shown in Fig. 6 comprises a support element (17) comprising a forward mounting section (22) and a rearward mounting section (21), the forward mounting section (22) extending forwards from an additional mounting element (18) mounted to the hull (1) towards and around the bridge (23), the forward mounting section (22) mounted to the bridge (23) and the hull (1) and the rearward mounting section (21) extending rearwards from the additional mounting element (18), the rearward mounting section (21) being arranged to be mounted to the hull by two outer towline stoppers (15A, 15B), the rearward mounting section (21) comprising a guiding element (20) extending between the two outer towline stoppers (15A, 15B) in a first plane substantially parallel to the deck (13). The towing stable (14) of the embodiment of the present invention shown in Fig. 6 further comprises one or more winches (12) mounted to the hull (1) centrally on or in close proximity to the central longitudinal axis (A) of the hull (1) rearwardly from the bridge (23), between the bridge (23) and the the stern of the towing vessel, the towing stable further comprising three inner towline stoppers (16A, 16B, 16B') mounted to the hull (1) rearwardly from the one or more winches, between the at least one winch and the stern of the towing vessel, the innermost inner towline stopper (16A) arranged on the central longitudinal axis (A) of the hull (1) and the two outermost inner towline stoppers (16B, 16B') arranged more rearwardly than the innermost inner towline stopper (16A), between the innermost towline stopper (16A) and the stern of the towing vessel, the two outermost inner towline stoppers arranged symmetrically with the same distance from both the innermost inner towline stopper (16A) and the central longitudinal axis (A) as to construct a triangle. The rearward mounting section (21) of the embodiment shown in Fig. 6, extends between the two outer towline stoppers (15A, 15B) in a semi-oval shape, such that the guiding element (20) stretches somewhat along the central longitudinal axis (A) between the outer towline stoppers, but does not follow the curvature of the gunwale (2) as shown in Fig. 2, such that the distance between the guiding element (20) and the gunwale (29) is not constant along the periphery of the guiding element (20). As demonstrated in Fig. 6, the embodiment of the towing stable provided, comprises a rearward mounting section (21) with guiding element (20) that extends towards and at least partly over the rearward propulsion system (25B), such that during direct towing, the towing point is directly above rearward propulsion system (25B).

[0081] Fig. 7 illustrates partly front view, partly side view of a vessel for towing, such as a tugboat, comprising a towing stable (14) according to one embodiment of the present invention. The tugboat shown in Fig. 6 comprises a hull (1) comprising a bridge (23), a deck (13), a rearward propulsion system (25B) and a keel (26). The towing stable (14) of the embodiment of the present invention shown in Fig. 7 comprises a support element (17) comprising a forward mounting section (22) and a rearward mounting section (21), the forward mounting section (22) extending forwards from an additional mounting element (18) mounted to the hull (1) towards and around the bridge (23), the forward mounting section (22) mounted to the bridge (23) and the hull (1) and the rearward mounting section (21) extending rearwards from the additional mounting element (18), the rearward mounting section (21) being arranged to be mounted to the hull by two outer towline stoppers (15A, 15B) (only one shown in Fig. 7), the rearward mounting section (21) comprising a guiding element (20) extending between the two outer towline stoppers (15A, 15B) in a first plane substantially parallel to the deck (13). The towing stable (14) of the embodiment of the present invention shown in Fig. 7 further comprises one or more winches (12) mounted to the hull (1) centrally on or in close proximity to the central longitudinal axis (A) of the hull (1) rearwardly from the bridge (23) and three inner towline stoppers (16A, 16B, 16B') mounted to the hull (1) rearwardly from the one or more winches, the innermost inner towline stopper (16A) arranged on the central longitudinal axis (A) (not shown in Fig. 7) at the center of the hull (1) and the two outermost inner towline stoppers (16B, 16B') arranged more rearwardly than the innermost inner towline stopper (16A), the two outermost inner towline stoppers arranged symmetrically from both the innermost inner towline stopper (16A) and the central longitudinal axis (A) as to construct a triangle.

[0082] Fig. 8a and 8b illustrate the position and the rotation possible by a towing vessel comprising a towing stable according to the present invention, during indirect towing procedure. The towing vessel shown in Fig. 8a and 8b comprises two propulsion systems aligned along the central longitudinal axis A of the hull (1), a towing stable (14) mounted to the hull (1) comprising innermost inner towline stopper (16A) engaging and directing towline (10) to an outer towline stopper (15A) engaging and directing the towline (10) from the hull (1) towards a ship to be towed (50), thereby creating a towing point at the outer towline stopper (15A) where the towline exits the towing vessel. As demonstrated in Fig. 8a and 8b, the towing vessel thereby has an increased rotatability and increased maneuvering abilities, for full utilization of the available space for towing and better utilization of the towing forces of the towing vessel, by the possibility of rotating the towing vessel as needed during the indirect towing procedure.

[0083] Fig. 9 illustrates a top view of an embodiment of a tugboat with a towing stable according to the present invention, demonstrating the arrangement of different elements of the towing stable along the length of the tugboat. The tugboat of the embodiment shown in Fig. 9 has a specific longitudinal length (L) along the central longitudinal axis (A). As demonstrated in Fig. 9, the central crosswise axis (B) marks the middle point of the longitudinal length (L), dividing the longitudinal length (L) of the hull (1) into two equal halves (50% - L) each spanning 50 percent of the longitudinal length (L) of the hull (1). As further demonstrated in Fig. 9, each of the two equal halves (50% - L) can be further divided into two equal halves (25% - L) each spanning 25 percent of the total longitudinal length (L) of the hull (1), and each of the two equal halves (25% - L) can be further divided into two equal halves (12.5% - L) each spanning 12.5 percent of the total longitudinal length (L). In the embodiment demonstrated in Fig. 9, all inner towline stoppers (16) are arranged within the dotted line marking the one-eight or 12.5% (12.5% - L) of the longitudinal length (L) of the hull (1), that is all the inner towline stoppers (16) are arranged within a distance of 12.5% of the longitudinal length (L) from the central crosswise axis (C). No Item 1Hull10Towline12Winch13deck14Towing stable15Outer towline stopper15AOuter towline stopper15BOuter towline stopper16Inner towline stopper16AInnermost inner towline stopper16BOutermost inner towline stopper17Support element18Additional mounting element19Copling between inner towline stoppers20Guiding element21Rearward mounting section22Forward mounting section23Bridge / wheelhouse / building25AForward propulsion system25BRearward propulsion system26Keel27Tow pin28Tow pin mounting stable29Gunwale50Ship to be towedACentral longitudinal axisBCentral crosswise axisDDistance between the forward and rearward propulsion systemCAngle between the towline and the central longitudinal axisLLongitudinal length of the hull50% - LHalf or 50% of the longitudinal length of the hull25% - LOne-fourth or 25% of the longitudinal length of the hull12.5% - LOne-eight or 12.5% of the longitudinal length of the hull

Claims

1. A hull (1) for a vessel for towing, comprising - a deck (13); - a forward propulsion system (25A) and a reward propulsion system (25B), the two propulsion systems aligned along the central longitudinal axis (A) of the hull (1); - at least one winch (12) comprising at least one towline (10); and - a towing staple (14) for guiding the at least one towline (10) wherein the towing staple (14) comprises: - two outer towline stoppers (15A, 15B), mounted to the hull (1); - a support element (17) comprising a forward mounting section (22) mounted to the hull (1) and a rearward mounting section (21) mounted to the hull (1), the rearward mounting section (21) comprising a guiding element (20) mounted to the hull (1) by means of the two outer towline stoppers (15A, 15B), the guiding element (20) extending between the two outer towline stoppers (15A, 15B) in a first plane substantially parallel to the deck (13) arranged for allowing the towline (10) to move freely along the periphery of the guiding element (20) between the two outer towline stoppers (15A, 15B); and - one or more inner towline stopper (16), mounted to the hull (1) arranged laterally amidships, centrally on or in close proximity to the longitudinal axis (A) of the hull (1), the at least one inner towline stopper (16) arranged for engaging with the at least one towline (10) extending from the at least one winch (12) towards the guiding element (20) and / or one of the two outer towline stoppers (15A, 15B); wherein one or more inner towline stopper (16) is arranged on and / or in close proximity to the central crosswise axis (B) of the hull (1).

2. A hull (1) according to claim 1, wherein one or more inner towline stopper (16) is arranged closer to the central crosswise axis (B) of the hull (1) than the reward propulsion system (25B).

3. A hull (1) for a vessel for towing according to claim 1 or 2, the hull having a longitudinal length (L), wherein the one or more inner towline stopper (16) is arranged such that the distance between one or more inner towline stopper (16) and the central crosswise axis (B) of the hull (1) is 25% or less of the longitudinal length (L) of the hull (1).

4. A hull (1) for a vessel for towing according to claim 3, wherein the distance between one or more inner towline stopper (16) and the central crosswise axis (B) of the hull (1) is 12.5% or less of the longitudinal length (L) of the hull (1).

5. A hull (1) for a vessel for towing according to any of the preceding claims, the hull having a longitudinal length (L), wherein the outer towline stoppers (15A, 15B) are arranged such that the distance between the outer towline stoppers (15A, 15B) and the central crosswise axis (B) of the hull (1) is 25% or less of the longitudinal length (L) of the hull (1).

6. A hull (1) for a vessel for towing according to any of the preceding claims, the hull (1) comprising an innermost inner towline stopper (16A) and two outermost inner towline stoppers (16B, 16B') and wherein: - the innermost inner towline stopper (16A) is arranged on the longitudinal axis (A) of the hull (1) closer to the winch (12) than the two outermost inner towline stoppers (16B, 16B') and is arranged as to engage the at least one towline (10) extending from the at least one winch (12); - the two outermost inner towline stoppers (16B, 16B') are arranged between the innermost inner towline stopper (16A) and the outer towline stoppers (15A, 15B) and / or the guiding element (20) and are arranged to engage the least one towline (10) extending from the innermost inner towline stopper (16A) towards the outer towline stoppers (15A, 15B) and / or the guiding element (20); wherein the three inner towline stoppers (16A, 16B, 16B') are all arranged on and / or in close proximity to the central crosswise axis (B) of the hull (1).

7. A hull (1) for a vessel for towing according to claim 6, the hull having a longitudinal length (L), wherein the three inner towline stoppers (16A, 16B, 16B') are arranged such that the distance between anyone of the three inner towline stoppers (16A, 16B, 16B') and the central crosswise axis (B) of the hull (1) is 25% or less of the longitudinal length (L) of the hull (1).

8. A hull (1) for a vessel for towing according to claim 7, wherein the distance between anyone of the three inner towline stoppers (16A, 16B, 16B') and the central crosswise axis (B) of the hull (1) is 12.5% or less of the longitudinal length (L) of the hull (1).

9. A hull (1) for a vessel for towing according to any of the preceding claims, wherein the towing staple (14) comprises at least one tow pin (27), mounted to the hull (1), the at least one tow pin (27) being reversibly displaceable between a retracted position and engaging position arranged for engaging with the guiding element (20), thereby creating a reversible physical obstruction for the movement of the towline (10) along the guiding element (20).

10. A hull (1) for a vessel for towing according to claim 9, wherein the at least one tow pin (27) is arranged directly above the rearward propulsion system (25B).

11. A method of using for a vessel for towing according to any of claims 1-10 for indirect towing, wherein the arrangement of the one or more inner towline stopper (16) and the two outer towline stoppers (15A, 15B) ensures that during the indirect towing procedure, wherein the towing point of the vessel is the point of engagement between any of the two outer towline stoppers (15A, 15B) and the towline (10).

12. A method of using a vessel for towing according to any claim 11, wherein the position of the towpoint enables a rotation of the hull (1).

13. A method of using for a vessel for towing according to any of claims 1-10, wherein the towline (10) exits the vessel at a point along the periphery of the guiding element (20) and wherein the towing point of the vessel is the point of engagement between one or more of the inner outer towline stoppers (16) and the towline (10).

14. A method of using for a vessel for towing according to any of claims 6-8, wherein the towline (10) exits the vessel at a point along the periphery of the guiding element (20) and wherein the towing point of the vessel is the point of engagement between the innermost inner towline stopper (16A) and the towline (10).

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