NO341826B1

NO341826B1 - Apparatus for connecting a drifting object to a towing vessel and method for using said apparatus

Info

Publication number: NO341826B1
Application number: NO20161225A
Authority: NO
Inventors: Thomas Netland
Original assignee: Stormlinker As
Priority date: 2016-07-25
Filing date: 2016-07-25
Publication date: 2018-01-29
Also published as: WO2018021917A1; NO20161225A1

Abstract

An apparatus (1) for connecting a drifting object (3) to a towing vessel (2); the apparatus (1) being arranged to be able to receive power from a power supply via a cable (13), the apparatus (1) comprising: - an attachment unit (12) arranged to be able to be connected to the towing vessel (2) via a towing line (15), the attachment unit (12) comprising an electromagnet (122a, 122b, 122c, 122d) for connecting the attachment unit (12) to the drifting object (3); and - a controllable, movable m em ber (11) arranged to be able to extend from the towing vessel (2), the movable member(11) having a first end portion arranged to be able to be connected to the towing vessel (2) and a second end portion capable of releasably carrying the attachment unit (12); characterisedin that the attachment unit (12) further com prises an abutment sensing means (123) for sensing abutment of the attachment unit (12) against the drifting object (3), the abutment sensing means (123) being in communication with a releasable gripping mechanism (111) for disconnecting the attachment unit (12) from the movable member(11) when abutment is sensed.An apparatus (1) for connecting a drifting object (3) to a towing vessel (2); the apparatus (1) being arranged to be able to receive power from a power supply via a cable (13), the apparatus (1) comprising: - an attachment unit (12) arranged to be able to be connected to the towing vessel ( 2) via a towing line (15), the attachment unit (12) comprising an electromagnet (122a, 122b, 122c, 122d) for connecting the attachment unit (12) to the drifting object (3); and - a controllable, movable m em ber (11) arranged to be able to extend from the towing vessel (2), the movable member (11) having a first end portion arranged to be able to be connected to the towing vessel (2) ) and a second end portion capable of releasably carrying the attachment unit (12); characterized in that the attachment unit (12) further com prises an abutment sensing means (123) for sensing abutment of the attachment unit (12) against the drifting object (3), the abutment sensing means (123) being in communication with a releasable gripping mechanism (111) for disconnecting the attachment unit (12) from the movable member (11) when abutment is sensed.

Description

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APPARATUS FOR CONNECTING A DRIFTING OBJECT TO A TOWING VESSEL AND METHOD

FOR USING SAID APPARATUS

The present invention relates to an apparatus for connecting a drifting object to a towing vessel. The apparatus comprises an attachment unit arranged to be able to be connected to the towing

5 vessel via a towing line. The attachment unit comprising an electromagnet for connecting the attachment unit to the drifting object. Furthermore, the apparatus comprises a controllable, movable member arranged to be able to extend from the towing vessel. The movable member has a first end portion arranged to be able to be connected to the towing vessel, and a second end portion capable of releasably carrying the attachment unit. The apparatus is arranged to be able to receive

10 power from a power supply via a cable.

Harsh weather conditions at sea, motor failure or other incidents can cause a floating object, such as for example a vessel, to go adrift. Drifting objects represent a considerable safety risk, particularly for fixed installations offshore and for other vessels. In order to regain control of these drifting objects, it is often necessary to connect a towing line to the superstructure of the drifting objects.

15 In what follows, a drifting object will also be denoted a drifting vessel. A drifting vessel, then, is not limited to a craft such as a boat or a ship. It is to be understood that the term drifting vessel in this text may be used for any item adrift on or near the surface of a body of water, wherein the item has the potential to pose a risk for fixed or floating constructions.

From prior art it is known to use a harpoon provided with a towing line to penetrate the hull of a

20 drifting vessel. Another known solution is to use a hook and line anchor that is harpooned to the deck of a drifting vessel in the hope that it snags on something when pulled back. These solutions have been shown to be both unsafe and unreliable, especially in harsh weather conditions.

It is also known to drop a line with a loop on the deck of a drifting vessel from a helicopter in an attempt to snag the loop on a pulley or another fixed item on the drifting vessel, and subsequently

25 connecting the line to a towing line on a towing vessel. This solution suffers from challenges with respect to harsh weather conditions with limited visibility from a helicopter and/or with strong wind.

Using a magnetic attachment unit to connect to a hull of a vessel is also known.

US8499709(B2) – Mooring system for a vessel – discloses a mooring system for a vessel that includes an attachment unit configured to be detachably attached to a hull of a vessel. The system is

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primarily for connecting a huge container ship to a mobile harbour for loading and/or unloading cargo at a distance from land, meaning the system is adapted for use in calmer waters and for bigger structures than what is typically the case for the current invention. It would be problematic to a system like the one disclosed in US8499709(B2) further from shore, in rougher conditions, as the

5 system offers a relatively rigid connection and a short distance between a structure/vessel comprising the system and a vessel connected to it.

US4030441(A) – Device for connecting tugboat with ship to be tugged – discloses how an electromagnet, secured to one end of a tug rope, which is to be paid out from a tugboat towards a ship to be tugged, may be used to rigidly secure a connection to the ship to be tugged. The device de-

10 scribed is primarily for use for tugging a ship to or from a dock, and like US8499709(B2) it discloses an invention for use near shore in relatively calm waters, an invention that offers a rigid connection and little distance between a vessel/structure and a vessel connected to it.

Connecting an attachment unit to a vessel adrift in harsh weather offshore is far more complicated and hazardous than connecting an attachment unit to a controlled vessel in calm waters at or near

15 shore. Harsher conditions may include bigger waves, which may lead to more relative movement between two vessels. More relative movement between two vessels in proximity to each other increases the risk of collisions, and if the two vessels are rigidly connected, the relative movement between them increases the risk of damage to the vessels and to any device, apparatus and/or system connecting the vessels.

20 The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.

The object is achieved through features, which are specified in the description below and in the claims that follow.

An object of the apparatus according to the present invention seeks to provide a safe and reliable

25 solution for securing a drifting object, such as a vessel, in harsh weather conditions.

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

In a first aspect the invention relates more particularly to an apparatus for connecting a drifting object to a towing vessel;

30 the apparatus being arranged to be able to receive power from a power supply via a cable, the apparatus comprising:

- an attachment unit arranged to be able to be connected to the towing vessel via a towing line, the attachment unit comprising an electromagnet for connecting the attachment unit to the drifting object; and

35 - a controllable, movable member arranged to be able to extend from the towing vessel, the mova

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ble member having a first end portion arranged to be able to be connected to the towing vessel and a second end portion capable of releasably carrying the attachment unit;

wherein the attachment unit further comprises an abutment sensing means for sensing abutment of the attachment unit against the drifting object, the abutment sensing means being in communica-

5 tion with a releasable gripping mechanism for disconnecting the attachment unit from the movable member when said abutment is sensed.

The invention has several advantages compared to prior art. It does not rely on penetration of the drifting object, as is required when using a harpoon. Nor does it rely on resilient, protruding, fixed objects onto which a hook or a loop can fasten. Furthermore, the invention is highly advantageous

10 compared to the aforementioned mooring systems in that the movable member will not stay connected to the drifting object for a significant period of time, as the abutment sensing means will activate the releasable gripping mechanism, thereby releasing the attachment unit from the movable member as soon as abutment against the drifting object is sensed. The release of the attachment unit from the movable member makes the connection between the towing vessel and the

15 drifting object less rigid, and it allows the towing vessel to create a greater distance between itself and the drifting object. These effects will reduce the negative risks involved in securing drifting objects in rough waters.

The releasable gripping mechanism may comprise an actuator and two gripping members, wherein the two gripping members may be arranged to engage with a handle comprised by the attachment

20 unit. The actuator may receive signals from the abutment sensing means when the abutment sensing means senses abutment, and act to control the release of the gripping members from the handle of the attachment unit. Other embodiments of a releasable gripping mechanism are possible, both other types of mechanical gripping mechanisms and/or electromagnetic gripping mechanisms.

The towing line may be comprised by the apparatus.

25 The apparatus may further comprise a plurality of electromagnets. This may be beneficial for the attachment unit’s ability to attach and to stay attached to a drifting vessel, particularly if one or more of the plurality of electromagnets should fail.

Any electromagnet comprised by the apparatus may be an energise-to-hold magnet or it may be an energise-to-release magnet. An energise-to-release magnet does not require a power source while

30 retaining its hold on a drifting vessel. This may be advantageous, as it means there will be no need to supply power to the electromagnet while towing a drifting vessel.

The attachment unit may further comprise a suction cup. The suction cup may further improve the attachment unit’s ability to attach and to stay attached to a drifting vessel.

Furthermore, the attachment unit may comprise a plurality of suction cups. This may further im-

35 prove the attachment unit’s ability to attach and to stay attached to a drifting vessel.

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The term “suction cup” may refer to any kind of vacuum or suction pad or cup or similar for adhering to nonporous surfaces by creating a partial vacuum. Creating the vacuum in a chamber between the suction cup and a nonporous surface may be done either by squeezing fluid out of the chamber or by pumping the fluid out of the chamber by use of a pump. If the suction cup requires a

5 pump for pumping fluid out of the chamber, the apparatus may comprise a pump for this purpose.

The pump may be connected to the power supply via a cable and be connected to the suction cup via a hose or similar. The pump and suction cup may be connected by the hose via a valve. The hose and/or the valve may be comprised by the apparatus.

The power supply may be arranged on the towing vessel, or it may be arranged in a suitable posi-

10 tion on the apparatus. One such suitable position may be on the attachment unit. The power supply may be any kind of power supply fit for the purpose, such as a battery or a diesel generator. By arranging the power supply on the attachment unit it is not necessary for the cable for connecting the power supply to the electromagnet to extend from the towing vessel to the attachment unit. Thus, having the power supply arranged on the attachment unit may be very advantageous. This,

15 however, may not be a practical solution for all embodiments of the invention, such as if energiseto-hold magnets are used for a long haul. The apparatus may use a plurality of power sources, which may be placed in different positions on the apparatus and/or the towing vessel.

The power supply may be connected to the apparatus by means of a cable. The cable may extend from the power supply to one or more parts on the attachment unit requiring power. The power

20 supply and/or the cable may be comprised by the apparatus.

The controllable, movable member may be any type of movable member suitable for the task, such as a crane beam or a telescoping boom. The movable member may be extendable and retractable in all directions, and it may be axially moveable. The mobility of the movable member is important, as it offers a versatility that may be required during operations in rough sea. The movable member

25 may be partly automated, or it may be fully automated. It may be controlled from the bridge on the towing vessel, or it may be controlled from the deck of the towing vessel.

The abutment sensing means may be any means for sensing when the attachment unit abut against a drifting vessel. Note that abutment is not limited to physical contact. To abut may mean to be adjacent to, so the abutment sensing means may be means of sensing proximity. The abutment

30 sensing means may be an instrument such as a proximity sensor, or it may be a simple mechanical contrivance. The mechanical contrivance may comprise a small, movable, metallic rod protruding from the attachment unit. The abutment sensing means may be connected to a mechanism that acts upon the sensing of abutment. The mechanism may release the attachment unit from the controllable, movable member. The mechanism may activate an energise-to-release magnet by dis-

35 connecting a power supply from it, or it may activate an energise-to-hold magnet by connecting a power supply to it. Furthermore, the mechanism may activate a pump for a suction cup.

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The apparatus may comprise a plurality of abutment sensing means placed in different positions on or through a connection surface of the attachment unit adapted to connect to a surface of the drifting vessel. When the attachment unit is moved towards a drifting vessel to connect to it, a first part of the connection surface may abut against the drifting vessel before a second part of the connec-

5 tion surface. In a first scenario, it may be beneficial if it is enough that any one of a plurality of abutment sensing means senses abutment for the attachment unit to be released from the movable member. In a second scenario, it may be beneficial if more than one, or even all, of a plurality of abutment sensing means senses abutment before the attachment unit is released. The first scenario will have a quick response time, with a reaction happening as soon as one part of the connection

10 surface abuts against the drifting vessel. The second scenario will require an even abutment of the connection surface against the drifting vessel, and thus secure a good connection between the two surfaces. In both scenarios, a plurality of abutment sensing means will be advantageous.

Furthermore, the apparatus may comprise lighting arrangements on the attachment unit and/or elsewhere on the apparatus. This may be advantageous by providing increased visibility when

15 controlling movement of the attachment unit towards a drifting vessel.

The apparatus may further comprise cleaning means, e.g. to clean debris from a hull of the drifting vessel, to clean the suction cups, and/or to clean the electromagnets prior to abutment of the attachment unit against the drifting vessel. This can help in ensuring a sufficient attachment of the attachment unit against a drifting vessel.

20 In a second aspect, the invention relates more particularly to a vessel comprising the apparatus according to the first aspect of the invention.

In a third aspect, the invention relates more particularly to a method for connecting a towing vessel to a drifting object by means of the apparatus according to the first aspect of the invention, wherein the method comprises the following steps:

25 - arranging the apparatus on the towing vessel;

- providing power to the apparatus;

- connecting the attachment unit to the towing vessel by means of a towing line;

- carrying the attachment unit towards the drifting object by means of the movable member;

- magnetically attach the attachment unit to the drifting object by activating the electromagnet; and

30 - releasing the attachment unit from the movable member,

wherein the step of

the step of releasing the attachment unit from the movable member being performed as a response to the abutment sensing means sensing an abutment of the attachment unit against the drifting object.

35 Releasing the attachment unit from the movable member immediately upon abutment of the attachment unit against the drifting vessel can be very advantageous, especially in rough conditions

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at sea. Without such a release mechanism, the two vessels may be more rigidly connected, which can be hazardous both for equipment and vessels and for crew.

Furthermore, the attachment of the attachment unit to the drifting vessel may be automated. The electromagnet may be automatically activated as a response to the abutment sensing means sens-

5 ing abutment of the attachment unit against the drifting vessel.

When the attachment unit is released from the movable member automatically upon abutment, it is of great importance that the attachment unit will attach itself to the drifting vessel substantially at the same time. With an energise-to-release magnet it is thus of great advantage that the power supply to the magnet is disconnected when abutment is sensed. If one or more energise-to-hold

10 magnets are being used, it is important that they are activated, i.e. connected to the power supply, when abutment is sensed.

The method may further comprise the steps of connecting a pump to a suction cup on the attachment unit by means of a hose, and creating a partial vacuum in a chamber between a surface of the drifting vessel and a suction cup on the attachment unit.

15 In the following are described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

Fig. 1 illustrates the apparatus, arranged on a towing vessel, with the movable member carrying the attachment unit;

Fig. 2 illustrates the apparatus, arranged on a towing vessel, with the movable member

20 carrying the attachment unit as the attachment unit abuts against a drifting vessel;

Fig. 3 illustrates the apparatus, arranged on a towing vessel, with the attachment unit attached to a drifting vessel after having been released from the movable member;

Fig. 4 shows the posterior side of the attachment unit as it is being carried by the movable member;

25 Fig. 5 shows the posterior side of the attachment unit after having been released by the movable member; and

Fig. 6 illustrates the front side of the attachment unit.

Figure 1 illustrates the apparatus 1, arranged on a towing vessel 2, with the movable member 11 carrying the attachment unit 12. The attachment unit 12 is connected to the movable member 11.

30 The attachment unit 12 is further connected to the towing vessel by a towing line 15, a cable 13 for providing power to the attachment unit 12 and a hose 14 for sucking fluid out of suction cups (not shown) on the attachment unit 12 to create vacuum. Furthermore, figure 1 shows a drifting vessel

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3.

Figure 2 shows the apparatus 1 as the attachment unit 12 abuts against the drifting vessel 3. The abutment is sensed by abutment sensing means (not shown), which activates the gripping mechanism 111 such that the attachment unit 12 will be released from the movable member 11.

5 Figure 3 shows the apparatus 1 after the attachment unit 12 has been released from the movable member 11. In this figure, the attachment unit 12 has attached to the drifting vessel 3.

Figure 4 and figure 5 illustrate a gripping mechanism 111, connecting the attachment unit 12 to the movable member 11, in an embodiment comprising two mechanical gripping members 111a, 111b. In figure 4 the gripping mechanism 111 is engaged with a handle 125 for the gripping members

10 111a, 111b on the attachment unit 12, securing the attachment unit 12 to the movable member 11, while in figure 5 the gripping mechanism 111 has released its grip on the attachment unit 12, thus releasing the attachment unit 12 from the movable member 11.

Figure 6 shows the front side of the attachment unit 12 – the side of the attachment unit 12 to abut against and attach to a drifting object. In the attachment unit 12 shown in this figure, there are four

15 suction cups 121a, 121b, 121c, 121d, two electromagnets 122a, 122b and an abutment sensing means 123.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between

20 parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The mere fact that certain measures are recited in mutually different dependent claims does not

25 indicate that a combination of these measures cannot be used to advantage.

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Claims

C l a i m s

1. An apparatus (1) for connecting a drifting object (3) to a towing vessel (2);

the apparatus (1) being arranged to be able to receive power from a power supply via a

5 cable (13),

the apparatus (1) comprising:

- an attachment unit (12) arranged to be able to be connected to the towing vessel (2) via a towing line (15), the attachment unit (12) comprising an electromagnet (122a, 122b, 122c, 122d) for connecting the attachment unit (12) to the drifting object (3); and

10 - a controllable, movable member (11) arranged to be able to extend from the towing vessel (2), the movable member (11) having a first end portion arranged to be able to be connected to the towing vessel (2) and a second end portion capable of releasably carrying the attachment unit (12);

c h a r a c t e r i s e d i n that

15 the attachment unit (12) further comprises an abutment sensing means (123) for sensing abutment of the attachment unit (12) against the drifting object (3), the abutment sensing means (123) being in communication with a releasable gripping mechanism (111) for disconnecting the attachment unit (12) from the movable member (11) when abutment is sensed.

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2. The apparatus (1) according to claim 1, wherein the attachment unit (12) comprises a plurality of electromagnets (122a, 122b).

3. The apparatus (1) according to claim 1 or 2, wherein at least one electromagnet (122a, 122b) is an energise-to-release magnet.

4. The apparatus (1) according to any one of the previous claims, wherein the apparatus (1)

25 comprises a power supply.

5. The apparatus (1) according to claim 4, wherein the power supply is arranged on the attachment unit (12), to supply power to the attachment unit.

6. The apparatus (1) according to any one of the previous claims, wherein the attachment unit (12) further comprises a suction cup (121a, 121b, 121c, 121d).

30 7. The apparatus (1) according to claim 6, wherein the apparatus (1) further comprises a pump for creating a partial vacuum in a chamber between a surface of the drifting object (3) and the suction cup (121a, 121b, 121c, 121d).

8. The apparatus (1) according to any one of the previous claims, wherein the abutment sensing means (123) is a proximity sensor.

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9. The apparatus (1) according to any one of the previous claims, wherein the attachment unit (12) comprises a plurality of abutment sensing means (123).

10. A towing vessel (2) comprising the apparatus (1) according to any one of the previous claims.

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11. A method for connecting a towing vessel (2) to a drifting object (3) by means of the apparatus (1) according to any of the claims 1-10, wherein the method comprises the following steps:

- arranging the apparatus (1) on the towing vessel (2);

- providing power to the apparatus (1);

10 - connecting the attachment unit (12) to the towing vessel (2) by means of a towing line (15);

- carrying the attachment unit (12) towards the drifting object (3) by means of the movable member (11);

- magnetically attach the attachment unit (12) to the drifting object (3) by activating the

15 electromagnet (122a, 122b); and

- releasing the attachment unit (12) from the movable member (11),

c h a r a c t e r i s e d i n t h a t :

the step of releasing the attachment unit (12) from the movable member (11) being performed as a response to the abutment sensing means (123) sensing an abutment of the

20 attachment unit (12) against the drifting object (3).

12. The method of claim 11, wherein the electromagnet (122a, 122b) is activated to magnetically attach the attachment unit (12) to the drifting object (3) automatically as a response to sensed abutment of the attachment unit (12) against the drifting object (3).

13. The method of claim 11 or 12, wherein the method further comprises the steps of:

25 - connecting a pump to a suction cup (121a, 121b, 121c, 121d) on the attachment unit by means of a hose (14); and

- creating a partial vacuum in a chamber between a surface of the drifting object (3) and the suction cup (121a, 121b, 121c, 121d) on the attachment unit (12).