GB2303584A - Improvements in Bulkheads - Google Patents

Abstract

A bulkhead (12) for location on the vehicle deck (10, 11) of a roll-on roll-off ferry comprises a support post (24) for fixing to the vehicle deck and a door (22, 23) pivotally mounted to the post. The door is movable between an open position, in which the door lies parallel to the vehicle lanes on the deck, and a closed position in which the door extends across at least a part of a vehicle lane. The edges of the door include seals to prevent passage of water around the door when in the closed position.

Description

IMPROVEMENTS IN BULKHEADS This invention relates to improvements in bulkheads, and in particular to bulkheads for use in roll on-roll off (ro-ro) ferries.

Recent incidents involving roll on-roll off (ro-ro) vehicle ferries have led the International Maritime Organisation (IMO) to establish improved safety procedures and standards. One of the most significant proposals relates to the provision of transverse or arthwartships bulkheads on the vehicle deck: in the absence of such bulkheads any water on a flooded deck, as may occur on the failure of a bow or stern door seal, is free to move across the length and breadth of the ship, with potentially disastrous effect on the stability of the vessel. Accordingly, newly built ferries will be designed to incorporate such bulkheads. However, existing ferries will have to be modified, by retrofitting bulkheads.

Ro-ro decks are typically six or seven "lanes" wide, and slightly narrower at the approaches to the bow and stern doors with the central portion of the deck being divided by a longitudinal bulkhead. The ro-ro decks are of sufficient height to accommodate commercial vehicles and a number of ferries also include hoistable platforms, to create two deck levels capable of carrying cars. The bulkheads currently being proposed extend across three or four lanes of the deck between the central longitudinal bulkhead and the outer walls of the deck. Thus, when a ferry is being loaded, the areas between the bulkheads must be filled in sequence. This creates difficulties in achieving a desired load distribution on the deck: at present the deck hands arrange the vehicles in lanes as they come onto the deck.In vessels provided with arthwartships bulkheads this is not possible and the vehicle distribution on the deck must be prearranged prior to the vehicles moving onto the deck. This requires the provision of extensive sorting areas on land within the port, where space may already be at a premium.

The large bulkheads which have been proposed require power to move them between the open and closed positions and safety restrictions make it likely that hydraulic motors would have to be used, requiring provision of extensive piping and hoses between the bulkhead motors and the hydraulic fluid sources. The proposed bulkheads would also be badly affected by any slight distortion of the ro-ro deck, as may occur when a ferry bumps into a quayside: a curtain or lowered bulkhead would be likely to jam on its tracks, and it would be difficult to maintain a seal between a large bulkhead and the warped deck. The proposed bulkheads would also likely have to be specially designed and manufactured for each ferry design, making installation expensive and time-consuming.

It is among the objects of the present invention to provide a bulkhead arrangement which obviates or mitigates one or more of these disadvantages.

According to the present invention there is provided a bulkhead for location on the vehicle deck of a roll on-roll off ferry, the bulkhead comprising: a support post for securing to the deck; and a door pivotally mounted to the post, the door being moveable between an open position, in which the door lies parallel to the vehicle lanes of the deck, and a closed position, in which the door extends across a vehicle lane, selected edges of the door including seal arrangements to prevent passage of water around the door when in the closed position.

The present invention also relates to a roll on-roll off ferry having a ro-ro deck including one or more of such bulkheads.

The use of a post to support the bulkhead door facilitates fitting of the bulkhead: the post is simply secured to the deck at a suitable location. The post may be permanently fixed to the deck, or may be removable to permit passage of wide loads.

Preferably, the door extends across no more than one lane when in the closed position. This permits vehicles to be distributed over the car deck by the deck hands in the conventional manner, on a "lane-by-lane" basis; it is not necessary to "fill" sections between bulkheads, as is the case with bulkheads which extend across the breadth of the deck. Conveniently, each door extends over approximately half a lane, such that two doors are required to close a lane. This minimises the area which must be left clear between the bulkhead and the vehicles on the deck to permit unobstructed opening and closing of the doors.

Preferably also, a post supports two doors, one extending to either side of the post.

Preferably also, each bulkhead includes first and second longitudinally spaced posts, the door being pivotally mounted to the first post and linked to the second post by a support frame. In the open position the door and frame are positioned between the posts, and in the closed position a portion of the frame extends between the free edge of the door and the second post.

Thus, both edges of the door are supported, and thus the door is capable of withstanding greater hydraulic loading. Conveniently, said frame portion is in the form of a hinged strut which, when extended, connects the door free edge and the second post. The length of the strut may be adjustable by means of, for example, a double eccentric pin\bush. The strut may be supported by a member pivotally connected between the first post and the strut hinge point. The support frame may also include means for locking the door in the closed position.

Preferably also, the door is manually moveable between the open and closed positions. This obviates the requirement to provide motors or other sources of motive power, and the associated controls. Thus the bulkhead will be relatively inexpensive and straightforward to fabricate and install, and will be reliable in operation.

The door may also be opened and closed relatively quickly.

Preferably also, the seal arrangements on the free and lower edges of the door are adjustable. Thus, the seals may be adjusted to accommodate irregularities in the cooperating seals and the deck surface.

This and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a sectional view of part of a roll on-roll off deck, including a bulkhead in accordance with the preferred embodiment of the present invention; Fig. 2 is a plan view of a bulkhead unit of the bulkhead of Fig. 1; Fig. 3 is a rear view of the door of the bulkhead unit of Fig. 2; Fig. 4 is a sectional view of a door-to-door seal of the bulkhead of Fig. 1; and Fig. 5 is a sectional view of a door-to-deck seal of the bulkhead of Fig. 1.

Reference is first made to Fig. 1 of the drawings which shows a section through part of a roll on-roll off (ro-ro) vehicle ferry. This particular ferry includes two ro-ro decks 10,11, the lower deck being provided with bulkheads 12 in accordance with a preferred embodiment of the present invention, one of which is shown. The portion of the deck 10 which is illustrated comprises four vehicle lanes between a central longitudinal bulkhead 14 and the side of the ship 16. The bulkhead 12 is formed of four gates 18,19,20,21 each comprising a pair of doors 22,23 being mounted to support posts 24 located between the vehicle lanes.

It will be noted that the bulkhead 12 does not extend over the full height of the deck 10. This allows hoistable platforms, one of which is illustrated in ghost outline at 26, to be provided above the bulkhead 12.

Reference is now also made to Figs. 2 and 3 of the drawings which illustrate portions of the bulkhead 12 in greater detail. Fig. 2 illustrates a bulkhead unit 28, to be provided spaced from the central longitudinal bulkhead 14 and the side 16 of the vessel, including two doors 22,23, in contrast to the units 28a,28b at the bulkhead 14 and the side 16, respectively, which include only a single door.

The unit 28 includes two support posts 24a,24b, and in this example the posts are both rectangular hollow sections, each provided with a bottom flange 30 which is bolted to a suitably reinforced portion of the deck 10.

The doors 22,23 are pivotally mounted to the first post 24a by four hinges 32, while the free edge of each door is connected by a respective strut 34,35 to the second post 24b. Each strut is hinged at 36 (see Fig. 3) and includes two triangular portions 38,39 pivotally mounted to the upper and lower door edges, respectively, and a rectangular portion 40, centrally mounted on the second post 24b. The length of each strut 34,35 may be varied by adjusting a double eccentric pin/bush at the hinge 36.

Each strut is supported by a rectangular frame portion 44 which extends from the first post 24a to the hinge 36.

The frame portion 44 includes two pins which engage corresponding slots 46 in the rectangular frame portion 40 of each strut 34,35, and each strut 34,35 may be collapsed by pulling on a handle 48 extending from each frame portion 44, to open the doors 22,23. Each door may be locked closed by a bolt 49 on the frame portion 40 which prevents movement of the rectangular frame portion pins in the slots 46. When the doors 22,23 are open, the doors 22,23, struts 34,35 and frame portions 44 are accommodated in the space between the two posts 24a,24b.

Seals 50,51,52 are provided around the pivot edge, lower edge and free edge of each door 22,23 to minimise leakage of water around the closed door. The seal 50 between the doors 22,23 and the first post 24a is simply a rectangular length of flexible waterproof material with its edge bolted to the door. The seal arrangement 52 at the door free edges is illustrated in Fig. 4 of the drawings, which illustrates the free edges 54,55 of two adjacent doors. Each door is formed of a pressed sheet with angled edges and the respective seal member 56,57 is bolted at 59 (see Fig. 3) to the door edge. One seal member 57 defines a rectangular open channel 58 which accommodates a rubber seal 60. The other seal member 56 includes a finger 62 which, when the doors are closed, engages the seal 60.The seal members 56,57 define slots to receive the securing bolts 59, and thus may be adjusted relative to the doors.

Reference is now made to Fig. 5 of the drawings which illustrates the seal arrangement 51 between the lower edge of the door and the deck. The seal arrangement 51 includes a seal member 64 somewhat similar to the seal member 56 described above, in that it defines an open channel 66 which accommodates a rubber seal 68.

This cooperates with the edge of a ramp member 70 fixed to the deck 10. Like the seal members 56,57 described above, the seal member 64 is fixed to the doors by bolts 59 and the height of the seal 68 may be adjusted as desired. Also, by use of appropriate spacers, the seal member 64 may be moved forwards or backwards relative to the door.

In use, a plurality of bulkheads 12, each formed from an appropriate number of units 18, will be provided on each ro-ro deck 10 at suitable locations on the deck.

When loading and unloading the vessel the doors 22,23 are opened to allow free passage of vehicles along the deck lanes. When a vessel is being loaded, deck hands will distribute the load across the deck 10 by directing vehicles into appropriate lanes. As the end of the line of vehicles in each lane approaches a bulkhead location, the respective bulkhead doors 23,24 may be closed across the lane by the deck hands. This allows the deck 10 to be loaded in conventional manner on a lane-by-lane basis and the relatively narrow doors 22,23 result in only minimal loss of space behind each gate. The ability to open and close the doors manually also allows the loading and unloading operations to be carried out relatively quickly as each door will only take a few seconds to open or close.

The embodiment illustrated and described herein is primarily intended for retro-fitting to existing ferries.

This is a relatively straightforward operation as no substantial modifications are required to the ship's structure. In addition, the majority of existing ferries may be provided with the bulkheads using "standardised" bulkhead units, for example the deck 10 illustrated in Fig. 1 is provided with three identical bulkhead units 28 and two single door units 28a,28b, which feature somewhat larger doors to close the wider vehicle lanes provided at the central bulkhead 14 and side 16.

It will clear to those of skill in the art that the above described embodiment is merely exemplary of the present invention and that various modifications and improvement may be made thereto without departing from the scope of the invention, for example: to allow the deck 10 to accommodate unusually wide loads, the posts 24 of the bulkhead units 28 adjacent the central longitudinal bulkhead 14 may be removable, and small crane jibs may be provided on the bulkhead 14 to lift the units and move them to one side as a wide load is loaded onto or unloaded from the deck 10.

Claims (16)

1. A bulkhead for location on the vehicle deck of a roll on-roll off ferry, the bulkhead comprising: a support post for securing to the deck; and a door pivotally mounted to the post, the door being moveable between an open position, in which the door lies parallel to the vehicle lanes of the deck, and a closed position, in which the door extends across at least a part of a vehicle lane, selected edges of the door including seal arrangements to prevent passage of water around the door when in the closed position.

2. The bulkhead of claim 1, wherein the post is adapted to be fixed to the deck.

3. The bulkhead of claim 2, wherein the post is adapted to be removable from the deck, to permit passage of wide loads.

4. The bulkhead of any of the preceding claims, wherein the door extends across no more than one lane when in the closed position.

5. The bulkhead of claim 4, wherein each door extends over approximately half a lane, such that two doors are required to close a lane.

6. The bulkhead of any of the preceding claims, wherein the post supports two doors, one extending to either side of the post.

7. The bulkhead of any of the preceding claims including first and second longitudinally spaced posts, the door being pivotally mounted to the first post and linked to the second post by a support frame.

8. The bulkhead of claim 7, wherein, in the open position, the door and frame are positioned between the posts, and in the closed position a portion of the frame extends between the free edge of the door and the second post.

9. The bulkhead of claim 8, wherein said frame portion is a hinged strut which, when extended, connects the door free edge and the second post.

10. The bulkhead of claim 9, wherein the length of the strut is adjustable.

11. The bulkhead of claim 9 or 10, wherein the strut is supported by a member pivotally connected between the first post and the strut hinge point.

12. The bulkhead of any of claims 7 to 11, wherein the support frame includes means for locking the door in the closed position.

13. The bulkhead of any of the preceding claims, wherein the door is manually moveable between the open and closed positions.

14. The bulkhead of any of the preceding claims, wherein the seal arrangements on the free and lower edges of the door are adjustable.

15. A roll on-roll off ferry having a ro-ro deck including one or more of the bulkheads as claimed in any of the preceding claims.

16. A bulkhead for a ro-ro ferry substantially as described herein and as illustrated in the accompanying drawings.