GB2073119A - Berthing unit - Google Patents

Abstract

A floating berthing unit 10 has a V-shaped notch 12 to receive the bow of a ship 11, the sides of the notch being provided with pneumatic roller fenders 18 to absorb the berthing energy of the ship. The other side of the unit is provided with fenders 23 of hardwood timber facing which are arranged to transmit the berthing energy to piles 17. The unit has both dry tanks and water ballast tanks. <IMAGE>

Description

SPECIFICATION Berthing unit The present invention relates to a unit for assisting in the berthing of vessels, and more particularly for vessels which berth end-on to the shore.

Ships, particularly Roll-On/Roll-Off ferries, often have to be carefully guided into position when berthing bow-on to a shore facility. Careful positioning can be time-consuming which is a disadvantage for a high-frequency service. In addition it is difficult to achieve without external assistance from tugs, winches, etc. and such assistance is not always commercially desirable where berthing time is at a premium. At present certain vessels, for example Cross-Channel ferries, are fitted with a structure around the bow. This structure is often termed a "cow-catcher" in view of its similarity in appearance to the device fitted in front of trains in the United States for clearing animals or debris from the track. An alternative name for the structure, especially in France, is a "moustache".The function of the cow-catchers is to guide the bow of a vessel into position during the docking operation.

However cow-catchers have certain disadvantages. Firstly they are quite heavy; they weigh between 20 and 30 tonnes taking into account associated stiffening of the vessel. If the need for this weight could be avoided the payload of the vessel could be increased by a corresponding amount. Secondly cow-catchers slow the vessel down by creating drag, and thus increasing fuel costs. Thirdly they set up a spraypattern over the foredeck which affects visibility and working conditions.

According to the present invention there is provided a berthing unit comprising a platform having an edge in which there is a recess shaped to receive the end of a ship, the surface of the recess being provided with energy-absorbing means for absorbing the berthing energy of a ship.

The unit is preferably in the form of a floating pontoon. The recess is preferably a generally Vshaped notch, which receives the bow of a ship, and the energy-absorbing means is preferably constituted by a plurality of pneumatic roller fenders, which also serve to locate the ship as it docks.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings of which: Figure 1 is a plan view of a berthing unit according to the present invention; Figure 2 is a sectional elevation of the unit of Figure 1 taken on line 2-2; Figure 3 is a side elevation of the unit of Figure 1 taken on line 3-3 with the state of the tide being lower than in Fig. 2; and Fig. 4 is a section taken on line i1 4 of Figure 1.

Referring now to Fig. 1 there is shown a floating berthing unit 10 in the form of a pontoon of mild steel construction. The unit has a recess 12 in which the bow of a ship 11 may be located.

The unit is positioned in a berth 1 3 by means of mooring lines 1 4 which pass around fair leads 1 5 and bollards 1 6 on the unit. The mooring lines maintain the pontoon in its relative position at the face of the berth prior to the ships arrival. The lines are of sufficient length to allow for the arc of movement caused by the change of tide, thus allowing the pontoon to ride up and down freely at the berth face. Berth 1 3 has berthing piles 1 7 protruding therefrom.

Recess 12 is a generally V-shaped notch and has spaced around its periphery four rotatable pneumatic fenders 1 8. These fenders are fitted with a high energy roller system each capable of absorbing 4.95 tonnes metres at maximum deflection. In order to present a normal face between the pneumatic fenders and the ships bow line, a small area of the ship's bow is preferably fitted with a fairing 1 9 in the area of contact between the ship and the pneumatic fenders. With a berthing speed of 0.5 knots the typical loading on the ship's bow fairing 1 9 at each of the four fender contacts at maximum deflection is 17.1 tonnes normal to the fairing, giving 42.3 tonnes/m2 loading. Recess 12 is also provided with solid D-section fenders 20, 21.

The outer periphery of the unit has half pipe corner fenders 22. Fenders of hardwood timber facing 23 are also provided, which serve to transmit the berthing energy of the ship from the pontoon to berthing piles 1 7. In certin tidal conditions the water level falls below the facing of berthing piles 17. To cater for these conditions a bulwark 26, see Figure 3, is built up from the deck level of the pontoon on both the port and starboard sides thereof.

The pontoon is provided with both dry tanks and water ballast tanks; access manholes for these are shown at 27.

Figure 2 shows the disposition of the berthing unit 10 and a shore-based movable ramp 29, which, after berthing of ship 11, engages ships ramp 30 to permit unloading of the ship. In the case of a Cross-Channel ferry, vehicles are driven along ramps 30, 31. Figure 2 shows the disposition at high tide, whereas at low tide the disposition is as shown in Figure 3. The shorebased ramp 29 is preferably rotatably mounted about a horizontal axis so that it may engage ship's ramp 30 at any state of the tide.

In use, a ship or other vessel 11 approaches recess 12, the vessel's bow locates into the recess and the pontoon centres on the berthing piles 1 7.

The berthing energy of the vessel is absorbed by the pneumatic fenders 1 8 and the resultant forces are transmitted through the pontoon to the berthing piles 17. The vessel may berth at a speed of up to 0.5 knots, at which speed the maximum loading on each of the berthing piles is within the range 56-72 tonnes. During berthing of the vessel the pontoon will trim in accordance with the resultant forces transmitted. The water ballast and the positioning of the fenders are arranged so as to keep the trimming effect produced to a minimum.

The berthing unit described above effectively performs the guiding function for berthing a vessel from a shore-based device rather than from the ship. This has the advantage of permitting extra pay-ioad on board the vessel to replace the no longer needed "cow-catcher" arrangement. In addition the disadvantages of the "cow-catcher" arrangement relating to the creation of drag and the production of extra spray are also avoided. The berthing unit also serves to absorb certain berthing forces from the docking vessel and to transmit these to a fixed shore structure behind it.

The berthing unit may readily be removed from a berth if a ship with a cow-catcher is to be docked there. Further the unit may be arranged to be used at any one of a plurality of sites, providing it fits the berths there. The unit requires very little maintenance; the only regular check required is of the state of inflation of the pneumatic fenders.

Although a berthing unit has been described which receives the bow of a ship, it may alternatively be shaped to receive the stern.

The term "ship" as used in this specification is intended to include all types of vessels such as ferries, tankers, etc.

Claims (9)

1. A berthing unit comprising a platform having an edge in which there is a recess shaped to receive the end of a ship, the surface of the recess being provided with energy-absorbing means for absorbing the berthing energy of a ship.

2. A berthing unit according to claim 1 wherein said energy-absorbing means is constituted by one or more pneumatic roller fenders.

3. A berthing unit according to claim 1 or 2, wherein said recess is a notch which is generally V-shaped in plan view.

4. A berthing unit according to any preceding claim which is in the form of a floating pontoon.

5. A berthing unit according to claim 4 and having water ballast tanks.

6. A berthing unit according to claim 4 or 5, wherein the side of the pontoon remote from said recess is provided with one or more further fenders.

7. A berthing unit according to claim 6, having a deck and one or more bulwarks built up from said deck in the region of said further fenders.

8. A berthing unit according to claim 6 or 7, wherein said further fenders are constituted by hardwood timber facing.

9. A berthing unit substantially as herein described with reference to the accompanying drawings.