Tug with an all around towing installation

Abstract

A tug (11) comprising a deck having an aft deck (16), a central deck (12) and a forward deck (15) and a rotatable towing installation (13) disposed on the central deck. The towing installation and central deck are sloping upwards from the aft deck to the forward deck with respect to a horizontal plane. The upward sloping angle (α) of the towing installation is at least 5 degrees. The design provides free towing all around in the horizontal plane in combination with sufficient bow height and buoyancy and in addition below deck space for e.g. additional accommodation.

Claims

1. A tug (11) comprising: a deck having an aft deck (16), a central deck (12) and a forward deck (15); and a rotatable towing installation (13) disposed on the central deck; characterized in that the towing installation and central deck slope upwards from the aft deck to the forward deck with respect to a horizontal plane; and in that an upward sloping angle (a) of the towing installation is at least 5 degrees; wherein the towing installation is rotatable 360 degrees with respect to the tug about the central deck.

2. A tug (11) according to claim 1, wherein the upward sloping angle (a) of the towing installation (13) is between 6 to 12 degrees.

3. The tug (11) according to claim 1, wherein the forward deck (15) slopes upward with a sloping angle (p) with respect to a horizontal plane in a range of 5 to 10 degrees.

4. The tug according to claim 1, wherein the aft deck (16) slopes downward with a sloping angle (γ) with respect to a horizontal plane in a range of 4 to 8 degrees.

5. The tug (11) according to claim 1, further comprising a secondary fixed towing point (22) disposed on the aft deck (16).

6. The tug (11) according to claim 1, further comprising a plate (27) for supporting the towing installation (13).

7. The tug (11) according to claim 6, wherein a diameter or width of the plate (27) is in g range of 70% to 100% of a beam of the tug (11).

8. The tug (11) according to claim 6, wherein the plate (27) contains machined grooves along an outer edge to mount rail segments.

9. The tug (11) according to claim 6, wherein the plate (27) has a circular shape.

10. The tug (11) according to claim 6, wherein the plate (27) has an oval or elliptical shape.

11. The tug (11) according to claim 6, wherein a thickness of the plate (27) is between 80 to 100 mm.

12. The tug (11) according to claim 6, wherein thickness of the plate (27) is 200 mm.

13. The tug (11) according to claim 6, further comprising a vertical outer pipe (28) supporting the plate (27); wherein the vertical outer pipe comprises curved surfaces.

14. The tug (11) according to claim 13, further comprising a vertical inner pipe (29); wherein the vertical outer pipe (28) and the vertical inner pipe support the plate (27); wherein the vertical outer pipe and the vertical inner pipe comprise curved surfaces.

15. The tug (11) according to claim 14, wherein the curved surfaces of the vertical outer pipe (28) and the vertical inner pipe (29) extend vertically in a straight line.

16. The tug (11) according to claim 13, wherein the vertical outer pipe (28) has outer edges which are at least 90% of a radius of the plate (27).

17. The tug (11) according to claim 14, further comprising an accommodation (18) disposed on top of the towing installation (13); wherein an outer perimeter of the accommodation aligns in a vertical direction with the vertical outer pipe (28) or the vertical inner pipe (29).

18. The tug (11) according to claim 1, wherein the towing installation (13) includes a circular ring-shaped base rotatable 360 degrees with respect to the tug about the central deck (12).

19. A method of assembling the tug (11) according to claim 1, comprising: constructing a central deck (12); positioning a plate (27) on a building floor; lifting the central deck and lowering the central deck upside down on a surface of the plate; and welding the plate to the central deck.

20. A tug (11) according to claim 1, wherein a rotating plane of the towing installation is parallel to the central deck.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more clearly understood from the following description of the embodiments thereof, when taken in conjunction with the accompanying drawings. However, the embodiment and the drawings are given only for the purpose of illustration and explanation, and are not to be taken as limiting the scope of the present invention, the scope of which is to be determined by the set of appended claims.

(2) FIG. 1 shows a tug according to a prior art all around towing design in a perspective view above waterline;

(3) FIG. 2 shows a tug according an embodiment of the invention;

(4) FIG. 3 shows the single heavy thick plate and supporting below pipe deck structure;

(5) FIG. 4 shows various supporting vertical structures, circular outside, curved or multi-chined inside; and both inner and outer multi-chined; and

(6) FIG. 5 shows the assembly procedure for welding a single heavy thick plate to the below deck structure.

DETAILED DESCRIPTION OF THE EMBODIMENT

(7) The conventional tug 1 represented in FIG. 1 is provided with a central deck 2, a circular towing installation 3 and a towing hook 4. Further, the forward deck 5 and aft deck 6 are shown and at the outer edge fitted with a railing/bulwark 7. The circular towing installation 3, consisting of a fixed inner ring-shaped base and a rotating outer ring, and the central deck 2 are positioned horizontally and the forward and aft deck 5, 6 are sloping upward to both ends. The upward sloping angle of the forward deck 5 and parallel bulwark 7 is in the range of 5-10 degrees to allow the towline to pass unhindered to the vessel towed. The downward sloping angle of the aft deck 6 and parallel bulwark 7 are in the range of 5-7 degrees, again to allow the towline to pass unhindered to the vessel towed. In FIG. 1, the central deck 2 is elevated above the connection with the forward and aft deck 5, 6, the height corresponding to typical railing/bulwark height of 700-900 mm. Inside the towing ring is the accommodation 8 and on top of the accommodation 8, the wheelhouse 9 and funnels 10. The towing installation 3 can for example consist of a circular rotating ring extending all around the circular fixed structure by means of rollers or bearings. And the towing installation 3 can for example consist of an oval shaped rail system where the multiple carriages move. These multiple carriages only extend over a small part of the circumference (not shown).

(8) The tug 11 represented in FIG. 2 is according to an embodiment of the invention. It is provided with a central deck 12, a circular towing installation 13 and a towing hook 14. Further the forward deck 15 and aft deck 16 are shown, again along the outer edge fitted with a bulwark 17, the accommodation 18, wheelhouse 19 and funnels 20. The towing installation 13 includes a fixed inner ring-shaped base and a rotating outer ring, which is rotatable 360 degrees with respect to the tug 11 about the central deck 12. The towing installation 13 in another embodiment may have a fixed inner ring-shaped base and a rotating (outer) carriage, which is 360 degrees rotatable with respect to the tug 11 about the central deck 12. The carriage may have a length in the range of 5-25% of the circumference of the ring shaped base. The towing installation 13 and central deck 12 are oriented at an upward sloping angle in the longitudinal forward direction from aft deck 16 to forward deck 15. In this embodiment, the surface of the central deck 12 is oriented parallel to the upward slope of the towing installation 13. In another embodiment the surface to the central deck 12 is oriented not necessarily parallel to the upward slope of the towing installation 12. The forward deck 15 slopes upward in a longitudinal forward direction to create more bow height 21, more buoyancy in the bow area and sufficient space 23 below deck. The aft deck 16 slopes downward in a longitudinal forward direction to create a lower deck for typical towing operations. The connection to the towed vessel can be established with a tow hook 14 on the towing installation 13, but can also be established with a winch or other suitable connection system (not shown). Further on the aft deck 16 a fixed winch 22 is shown for conventional towing over the stern. This can also be a towing hook or any suitable connection (not shown).

(9) FIG. 3 represents a side view of the tug 11 according to the embodiment, with a towing installation 13, a tow hook 14, a central deck 12 and an increased bow height 21 and more volume in the bow area 23. Further there are three sloping angles: α for the angle between the horizontal line and the sloping angle of the towing installation 13, β for the angle between the horizontal line and the sloping angle of the forward deck 15 and bulwark 17, and γ for the angle between the horizontal line and the sloping angle of the aft deck 16 and bulwark 17. The towing installation 13 is mounted on the single heavy thick plate 27 and is positioned at the aft end above the height of the aft deck 16 plus bulwark 17 and at the forward end above the height of the forward deck 15 plus bulwark 17. For reasons of stability the towing installation 13 shall be close to the top of the bulwark 17. Height between towing installation 13 and bulwark 17 shall be e.g. in the range of 250-750 mm. The bulwark 17 on aft and forward deck 16, 15 enables safe crew operations. The central deck 12 has no bulwark along the outer sides and the crew is intended to move only near the centerline of the central deck 12 and not near the sides.

(10) In another embodiment, the central deck 12 has the same height but along the sides the height is reduced over a width of e.g. 600-1000 mm and fitted with a bulwark 17. Hereby the crew can move safely along the sides of the central deck 12. This embodiment can be applied for larger sized (sea going) tugs. In another embodiment, the whole central deck 12 moves down with e.g. 700-900 mm and is fitted along the sides with a bulwark 17; the aft deck 16 aligns with the aft end of the central deck 12 and the forward deck 15 aligns with the forward end of the central deck 12.

(11) In another embodiment, a railing is fitted inside the towing installation to enable the crew to move safely between the accommodation 18 and towing installation 13. Also various combinations with and without bulwark 17 are possible, depending on the intended purpose of the tug 11. On the aft deck 16 the optional secondary towing point 22, in this case shown as a winch and a towline 24 over the stern 26, which can be used for conventional towing.

(12) The upward sloping angle α of the towing installation 13 is between 5 to 12 degrees. The forward deck 15 slopes upward with a sloping angle β with respect to a horizontal plane in the range of 5 to 10 degrees. The aft deck 16 slopes downward with a sloping angle γ with respect to a horizontal plane in the range of 4 to 8 degrees.

(13) FIG. 4 represents a cross section over the centre line to port side, with the towing installation 13 and the tow hook 14, the single heavy thick plate 27 welded on top of the vertical outer pipe structure 28 and the inner pipe structure 29 and the connecting plate structures 30 between the outer and inner pipes 28, 29. Only the main structural members are shown. Both supporting pipe structures 28 and 29 extend vertically and also the accommodation 18 outside structure. Likewise, the curved surfaces of the supporting pipe structures 28, 29 are also extended vertically.

(14) FIG. 5 shows an advantageous assembly procedure of ship production. The single heavy thick plate 27 is first constructed on the work floor of the ship yard, next the central deck 12 is built with all supporting structural members and both outer 29 and inner 28 vertical support structures including connecting plate structures 30. This can be built in standard upright condition. For assembly the central deck 12 is lifted up, turned upside down and lowered on the heavy thick plate 27, followed by full welding of both components. Finally, the central deck 12 and welded heavy plate 27 are lifted up, turned back in upright position and mounted on the other building blocks of the tug 11. Before assembly, the heavy thick plate 27 can be machined on the work floor of the ship yard, this can include grooves along the outer edge on one side or on both sides.

(15) Although the invention has been described above with reference to a preferred embodiment, numerous modifications may be made without departing from the scope of the present application. The all around towing installation may be constructed in all kind of different arrangements of bearings, rails and rollers both on fully circular shapes and on oval or non-circular shapes.