CA2354729A1 - Apparatus for stabilizing a damaged ferry - Google Patents
Apparatus for stabilizing a damaged ferry Download PDFInfo
- Publication number
- CA2354729A1 CA2354729A1 CA 2354729 CA2354729A CA2354729A1 CA 2354729 A1 CA2354729 A1 CA 2354729A1 CA 2354729 CA2354729 CA 2354729 CA 2354729 A CA2354729 A CA 2354729A CA 2354729 A1 CA2354729 A1 CA 2354729A1
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- Canada
- Prior art keywords
- ferry
- water
- stern
- ballast tanks
- bow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B43/00—Improving safety of vessels, e.g. damage control, not otherwise provided for
- B63B43/02—Improving safety of vessels, e.g. damage control, not otherwise provided for reducing risk of capsizing or sinking
- B63B43/04—Improving safety of vessels, e.g. damage control, not otherwise provided for reducing risk of capsizing or sinking by improving stability
- B63B43/06—Improving safety of vessels, e.g. damage control, not otherwise provided for reducing risk of capsizing or sinking by improving stability using ballast tanks
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B11/00—Interior subdivision of hulls
- B63B11/02—Arrangement of bulkheads, e.g. defining cargo spaces
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
- B63B35/54—Ferries
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Barrages (AREA)
Abstract
An apparatus is disclosed for stabilizing a damaged ferry, the ferry having a bow incorporating a loading door for loading and unloading vehicles and the bow or loading door or any other part of the hull above the lower vehicle deck being damaged and allowing external water introduction, the apparatus comprising means for directing intake water from outside the ferry and the external water into lower stern ballast tanks, whereby the damaged bow or loading door is raised above the water line by lowering the stern of the ferry and the ferry is maintained at an even keel. The ferry can also sustain hull damage below the lower vehicle deck and remain operational by restricting incoming water introduction to a limited number of lower compartments.
Description
APPARATUS FOR STABILIZING A DAMAGED FERRY
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
This invention relates to ferry stabilization apparatuses, and particularly to apparatuses that prevent listing of the vessel while preventing, delaying, or controlling the sinking of a damaged ferry.
Standard ferry construction uses watertight decks for vehicle storage. While this may provide some advantages, the watertight decks render ferries inherently unstable in the event of water intake within the deck areas. Upper and lower vehicle decks are normally positioned above the water line, as is the weight of vehicles and most of the ship superstructure. This has the effect of making the ferry highly unstable when water is introduced to the watertight decks, such as would result from damage to the loading doors or some portions of the hull above the lower vehicle deck. The result is that the ferry can potentially list due to the weight of vehicles, the water within the watertight decks, and the ferry superstructure, and the movement of the water back and forth within the watertight vehicle decks will further this, and the ferry will eventually tip onto its side.
The development of the present invention was necessitated by the limitations of the standard ferry structure, in that some means are required for countering the detrimental effect of water introduced by loading door damage or damage to the hull above the lower vehicle deck. In particular, some means are required for maintaining an even keel during water intake, such as where water is situated in the lower stern rather than the vehicle decks, while limiting further intake of water through the damaged portion of the ferry.
In response to this problem, the present invention seeks to provide an apparatus for controlling the water intake from the damaged bow above the lower vehicle deck or at the loading door and moving it to ballast tanks in the lower stern, port, and starboard of the vessel to assist in raising the damaged portion of the ferry above the water line by lowering the stern.
Standard ferry construction fails to address this problem in this manner, employing small bulge pump mechanisms only to move the minimal amount of water that arises due to the usual seepage that develops in a ship's hull or water used for cleaning the ship's interior. While this may meet those specific needs, it cannot address the large quantity of water that is taken in through significant hull damage, nor could it address the volume of water from even a minor hull breach. This is the case with many known types of ships. Some ships address the problem by being divided into watertight compartments that serve to limit the impact of hull damage by flooding only the damaged compartment, but this fails to address instances of substantial hull breach and concerns about vessel capsize. The present invention provides a means whereby water intake from the damaged portion of the ferry is controlled and the further intake of water is limited or eliminated entirely.
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
This invention relates to ferry stabilization apparatuses, and particularly to apparatuses that prevent listing of the vessel while preventing, delaying, or controlling the sinking of a damaged ferry.
Standard ferry construction uses watertight decks for vehicle storage. While this may provide some advantages, the watertight decks render ferries inherently unstable in the event of water intake within the deck areas. Upper and lower vehicle decks are normally positioned above the water line, as is the weight of vehicles and most of the ship superstructure. This has the effect of making the ferry highly unstable when water is introduced to the watertight decks, such as would result from damage to the loading doors or some portions of the hull above the lower vehicle deck. The result is that the ferry can potentially list due to the weight of vehicles, the water within the watertight decks, and the ferry superstructure, and the movement of the water back and forth within the watertight vehicle decks will further this, and the ferry will eventually tip onto its side.
The development of the present invention was necessitated by the limitations of the standard ferry structure, in that some means are required for countering the detrimental effect of water introduced by loading door damage or damage to the hull above the lower vehicle deck. In particular, some means are required for maintaining an even keel during water intake, such as where water is situated in the lower stern rather than the vehicle decks, while limiting further intake of water through the damaged portion of the ferry.
In response to this problem, the present invention seeks to provide an apparatus for controlling the water intake from the damaged bow above the lower vehicle deck or at the loading door and moving it to ballast tanks in the lower stern, port, and starboard of the vessel to assist in raising the damaged portion of the ferry above the water line by lowering the stern.
Standard ferry construction fails to address this problem in this manner, employing small bulge pump mechanisms only to move the minimal amount of water that arises due to the usual seepage that develops in a ship's hull or water used for cleaning the ship's interior. While this may meet those specific needs, it cannot address the large quantity of water that is taken in through significant hull damage, nor could it address the volume of water from even a minor hull breach. This is the case with many known types of ships. Some ships address the problem by being divided into watertight compartments that serve to limit the impact of hull damage by flooding only the damaged compartment, but this fails to address instances of substantial hull breach and concerns about vessel capsize. The present invention provides a means whereby water intake from the damaged portion of the ferry is controlled and the further intake of water is limited or eliminated entirely.
2. DESCRIPTION OF THE BACKGROUND ART
Prior attempts to provide water craft stabilization apparatuses as part of an invention include Canadian Pat. No. 1,311,968, wherein is disclosed an icebreaking ship that, among other things, utilizes trimming and ballasting as a means of increasing the ice channel width by lowering the stern (or the bow in sternway travel). However, this invention only addresses the problem of increasing the ice channel width, and it does not discuss ways to use ballasting as a means of countering water intake from loading door damage or damage to the hull above the lower vehicle deck.
U.S. Pat. No. 3,871,320 discloses an apparatus for counteracting hull tilting during loading or unloading of heavy cargo. As an alternative to stationary or floating cranes as a means of ensuring vessel stability during loading or unloading, the invention provides an apparatus whereby supporting leg mechanisms in contact with the quay are used along with manometer-controlled ballast trimming. It is disclosed that ballast trimming alone would be "extremely risky and dangerous" during loading and unloading without the supporting leg mechanisms, so the ballast trimming is viewed as merely supplemental. There is no discussion of how ballast trimming might be used to raise a damaged portion of the vessel by lowering the opposite end, as in the present invention.
U.S. Patent No. 4,872,118 discloses a system for the automated monitoring of a vessel's trim and stability, whereby the efficiency of vessel operation and the accuracy of computation of the vessel's metacentric height are enhanced. Ballasting is used in the invention, but not in a manner addressed to the unique problem of bow or loading door damage and incoming water control.
While the prior art speaks of ballasting as a means of controlling a vessel's trim and stability, and even of lowering a portion of the vessel in the case of Canadian Pat. No.
1,311,968, nowhere is the problem of incoming water control
Prior attempts to provide water craft stabilization apparatuses as part of an invention include Canadian Pat. No. 1,311,968, wherein is disclosed an icebreaking ship that, among other things, utilizes trimming and ballasting as a means of increasing the ice channel width by lowering the stern (or the bow in sternway travel). However, this invention only addresses the problem of increasing the ice channel width, and it does not discuss ways to use ballasting as a means of countering water intake from loading door damage or damage to the hull above the lower vehicle deck.
U.S. Pat. No. 3,871,320 discloses an apparatus for counteracting hull tilting during loading or unloading of heavy cargo. As an alternative to stationary or floating cranes as a means of ensuring vessel stability during loading or unloading, the invention provides an apparatus whereby supporting leg mechanisms in contact with the quay are used along with manometer-controlled ballast trimming. It is disclosed that ballast trimming alone would be "extremely risky and dangerous" during loading and unloading without the supporting leg mechanisms, so the ballast trimming is viewed as merely supplemental. There is no discussion of how ballast trimming might be used to raise a damaged portion of the vessel by lowering the opposite end, as in the present invention.
U.S. Patent No. 4,872,118 discloses a system for the automated monitoring of a vessel's trim and stability, whereby the efficiency of vessel operation and the accuracy of computation of the vessel's metacentric height are enhanced. Ballasting is used in the invention, but not in a manner addressed to the unique problem of bow or loading door damage and incoming water control.
While the prior art speaks of ballasting as a means of controlling a vessel's trim and stability, and even of lowering a portion of the vessel in the case of Canadian Pat. No.
1,311,968, nowhere is the problem of incoming water control
3 addressed. The present invention offers a novel solution to this problem using ballasting technology.
SUMMARY OF THE INVENTION
The principal object of this invention is, therefore, to seek to provide an apparatus whereby, upon water introduction resulting from bow damage above the lower vehicle deck or at the loading door, water is taken into ballast tanks in the lower stern, port, and starboard of a ferry to lower the stern of the vessel while maintaining an even keel, raising the damaged portion of the vessel above the water line and preventing further water intake.
Water already within the vessel moves by gravity to the lower stern ballast tanks to assist in raising the damaged portion of the vessel above the water line.
Other objects will appear from the description and the drawings.
Accordingly, the present invention seeks to provide an apparatus for stabilizing a damaged ferry, the ferry having a bow incorporating a loading door for loading and unloading vehicles and the bow or loading door being damaged and allowing external water introduction, the apparatus comprising means for directing intake water from outside the ferry into lower stern ballast tanks, whereby the damaged bow or loading door is raised above the water line by lowering the stern of the ferry. Water is optionally taken into the port and starboard ballast tanks to ensure a more even keel. Water that has already entered the vessel through the damaged bow or loading door or any location above the lower vehicle deck moves across the vehicle decks and flows by gravity into the ballast tanks at stern. The result is that the damaged portion of the vessel is above the water line, further water intake is halted, and the vessel is on an even keel
SUMMARY OF THE INVENTION
The principal object of this invention is, therefore, to seek to provide an apparatus whereby, upon water introduction resulting from bow damage above the lower vehicle deck or at the loading door, water is taken into ballast tanks in the lower stern, port, and starboard of a ferry to lower the stern of the vessel while maintaining an even keel, raising the damaged portion of the vessel above the water line and preventing further water intake.
Water already within the vessel moves by gravity to the lower stern ballast tanks to assist in raising the damaged portion of the vessel above the water line.
Other objects will appear from the description and the drawings.
Accordingly, the present invention seeks to provide an apparatus for stabilizing a damaged ferry, the ferry having a bow incorporating a loading door for loading and unloading vehicles and the bow or loading door being damaged and allowing external water introduction, the apparatus comprising means for directing intake water from outside the ferry into lower stern ballast tanks, whereby the damaged bow or loading door is raised above the water line by lowering the stern of the ferry. Water is optionally taken into the port and starboard ballast tanks to ensure a more even keel. Water that has already entered the vessel through the damaged bow or loading door or any location above the lower vehicle deck moves across the vehicle decks and flows by gravity into the ballast tanks at stern. The result is that the damaged portion of the vessel is above the water line, further water intake is halted, and the vessel is on an even keel
4 to allow for continued operation of the vessel or removal of passengers without danger of capsize. The present invention seeks to provide an apparatus for stabilizing a damaged ferry whereby a ferry could sustain any reasonably foreseeable damage at any point on the hull from keel to bridge and from bow to stern and still remain afloat.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, according to a preferred embodiment of the invention:
Figure la is a cross-sectional view of a standard ferry from port to starboard, showing water trapped in the watertight decks Figure 1b is a cross-sectional view of a standard ferry from port to starboard, showing water trapped in the watertight decks and the resultant capsize;
Figure 1c is a cross-sectional view of a ferry from port to starboard that takes incoming water into the lower stern of the vessel to maintain an even keel and prevent capsize Figure 2 is a cross-sectional port view of the present invention from bow to stern;
Figure 3 is a cross-sectional port view of the present invention from bow to stern demonstrating how controlled water intake raises the damaged portion of the ferry out of the water;
Figure 4 is a cross-sectional plan view of the present invention demonstrating the placement of the four ballast tanks, the watertight engine room, and the forward watertight compartments; and Figure 5 is a detailed cross-sectional view of the grating and fire damper arrangement.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now in detail to the Figures, Figure la shows upper and lower vehicle decks 28 and 30, the weight of vehicles, and most of the ship superstructure as normally positioned above the water line 70. As a result, the ferry is highly unstable when water 72 is introduced to the watertight decks as the result of hull or door damage. As shown in Figures 1a and 1b, the ferry may list due to the weight of vehicles, the water within the watertight decks, and the ferry superstructure, and the movement of the water back and forth within the watertight vehicle decks will increase the risk of capsize.
The ferry stabilization apparatus shown in Figures 2 to 5 is a preferred embodiment of the invention, comprising a system of ballast tanks 38a, 38b, 40, and 42 and means for directing water from inside and outside a ferry 10 into the ballast tanks, whereby a damaged section 24 of the ferry 10 is raised above the water line 70.
The bow 12 of the ferry 10 incorporates a loading door 22 in order to load and unload vehicles or other cargo (not shown) as desired, in a manner standard in ferries of the type. Vehicles are loaded onto the upper vehicle deck 28 and lower vehicle deck 30, and unloaded therefrom upon reaching their destination.
Vehicles can also be loaded and unloaded using a stern door 100.
The movement of the ferry 10 is controlled from within a bridge 32, and an engine room 36 is watertight and located toward the stern 14 of the ferry 10. Movement between the various areas of the ferry 10 is facilitated by means of passage sections 112, which may incorporate stairs, elevators, and/or passageways, including watertight or semi-watertight doors.
As can be seen by reference to Figure 4, stern ballast tanks 38a and 38b are situated in the stern 14 of the ferry 10. The starboard ballast tank 40 and port ballast tank 42 are located, respectively, in the starboard 16 and port 18 of the lower section of the ferry 10, to each side of the watertight engine room 36. The lower section of the ferry 10 forward of the watertight engine room 36 is divided into three watertight compartments 142, 144, and 146. The stern ballast tanks 38a and 38b are fitted with stern fast water intake doors 46a and 46b, respectively, to allow for water from outside the hull of the ferry 10 to enter the stern ballast tanks 38a and 38b, and are also fitted with air vents 62 to allow for the escape of displaced air within the stern ballast tanks 38a and 38b upon the entry of water. The starboard ballast tank 40 and port ballast tank 42 are fitted with air vents 62. Intake door controls 76 are located within the bridge 32.
The upper vehicle deck 28 and lower vehicle deck 30 are each fitted with a ballast tank grating 60 to allow for water held on the upper vehicle deck 28 and lower vehicle deck 30 to be directed into the stern ballast tanks 38a and 38b. The water passes into the stern ballast tanks 38a and 38b through the opening of fire rated dampers 68 which are situated beneath the ballast tank grating 60. As can be seen in Figure 5, the upper ends of the fire rated dampers 68 are attached to a deck 30 by means of hinges 116. Structural beams 120 are spaced as required to support the deck 30 and its load of vehicles. The structural beam 120, which supports the grating 60, also supports steel hangers 119 which in turn support the platform 69. The fire rated dampers 68 are normally in a closed position, their lower ends in contact with the platform 69 due to the action of hydraulic cylinders 148a and 148b. The hydraulic cylinders 148a and 148b are designed to control the opening and closing of fire rated dampers 68. Water passes through the grating 60 and collects on the platform 69, and the hydraulic cylinders 148a and 148b are employed to open fire rated dampers 68 and allow water to pass into the stern ballast tanks 38a and 38b and to close the fire rated dampers 68 when water ceases to flow through the grating 60, preventing water in the stern ballast tanks 38a and 38b from being reintroduced to the deck 30. Controls 108 (see Figures 2 and 3) are located adjacent the hydraulic cylinders 148a and 148b so that the ~ter~~ ballast tanks 38a and 38b can be left empty or filled to any desired level, with additional master controls 109 (not shown) on the bridge 32.
The water level in the bow 12 of the ferry 10 is monitored by means of loading door television cameras 26, with bridge television monitors 34 located on the bridge 32. The water level in the stern ballast tanks 38a and 38b, starboard ballast tank 40, and port ballast tank 42 is monitored by means of ballast tank television cameras 44 which are trained on water level markings 114 on the tank sides, with bridge television monitors 34 located on the bridge 32.
Having fitted the ferry 10 with the ferry stabilization apparatus described above, the utility of the present invention becomes clear in the following situation. Objects in the water or heavy wave action can cause damage to the bow 12 or loading door 22 of the ferry 10, leading to water intake at the damaged section 24.
Wave action will increase the amount of external water coming in through the damaged section 24, so the captain of the ferry 10 should turn the bow 12 of the ferry 10 away from the wind and waves in order to decrease introduction of more external water.
Stern fast water intake doors 46a and 46b are opened fully, allowing for intake water to move rapidly into the stern ballast tanks 38a and 38b and displacing any air within the stern ballast tanks 38a and 38b through air vents 62. Since ferry designers would probably include beams, floors, and partitions inside the stern ballast tanks 38a and 38b for structural reasons, openings in the floors and partitions would be necessary for the passage of water, and the presence of these structural obstacles would hinder the rapid motion of water within the tanks.
The controlled introduction of intake water to the stern 14 of the ferry 10 by means of intake door controls 76, which are similar in operation to the controls used on submarines for fast water intake hatches, will cause the stern 14 to settle lower, resulting in a corresponding rise of the bow 12, which slows down or halts new external water entry at the damaged section 24 by raising the damaged section 24 above the water line 70. The ferry 10 will likely only need to be inclined to a maximum of 6 degrees off the level of the water line 70.
When required to maintain an even keel starboard to port, some of the water in the stern ballast tanks 38a and 38b can be moved into the starboard ballast tank 40 and port ballast tank 42 by means of vertically operated flood gates 102a and 102b, respectively. Where conditions are such that the ferry 10 is subject to rolling from side to side, similar amounts of water should be introduced to the stern ballast tanks 38a and 38b as the ferry 10 rolls alternately to port or starboard, assisting in maintaining an even keel. However, should an uneven amount of water accumulate in the stern ballast tank 38a or 38b, the extra water could be moved by means of flood gates 102a or 102b. Flood gate controls 106 are located on the bridge 32. Maintaining an even keel will enable the officers and crew to keep the ferry 10 afloat and operational longer, also increasing the possibility of a safe and orderly vessel abandonment by passengers on a passenger deck 20 into life boats 64, should this become necessary given the extent of vessel damage or the weather conditions. Holding the water in the lower section of the ferry rather than trapping it within upper and lower vehicle decks 28 and 30 helps prevent listing of the ferry 10 to starboard 16 or port 18.
The stern tank is divided into stern ballast tanks 38a and 38b by means of a stern tank divider 110. This division allows for more effective control of the water contained therein. The stern tank divider 110 is fitted with stern tank floodgates 104, which are controlled by flood gate controls 106. When the ferry 10 is rolling due to external conditions, stern tank floodgates 104, which are normally in an open position, can be closed to prevent ballast from surging back and forth from starboard to port, thereby considerably reducing the degree of roll.
The external water that has already entered the ferry 10 will need to be directed away from the bow 12 of the ferry 10 to allow for the rise of the bow 12 due to the settling of the stern 14.
For this purpose, gravity flow is employed. Water on the upper and lower vehicle decks 28 and 30, given the tilt to stern 14 due to the settling of the stern 14, will flow toward the stern 14.
The fire rated dampers 68 would open by use of the control 108 and activation of the hydraulic cylinders 148a and 148b, allowing for movement of the external water into the stern ballast tanks 38a and 38b. This assists in the settling of the stern 14. The system of grating and fire rated dampers could also be used on ferries incorporating inclined vehicle decks. The external water that has settled in the bow 12 of the ferry 10 moves into the stern ballast tanks 38a and 38b, and then into the starboard ballast tank 40 and port ballast tank 42. Loading door television cameras 26 and ballast tank television cameras 44 are used to monitor the movement of water within the ferry 10, with bridge television monitors 34 being located on the bridge 32.
In the event that damage occurs at some other section of the hull, the various empty ballast tanks and forward watertight compartments could act as flotation means, increasing the stability of the ferry 10. For example, where damage occurs to the front or midship area below the lower vehicle deck 30, that area would flood and act as ballast but other sections-specifically the area above the lower vehicle deck 30, tanks 38a, 38b, 40, and 42, and watertight engine room 36-would provide flotation for the ferry 10, promoting stability and maneuverability despite the incline to the bow 12. In the event of damage to the stern 14 above the lower vehicle deck 30, some external water would flow through the grating 60 and into the tanks 38a and 38b, settling the ferry 10 by the stern 14 and enabling an even keel, and preventing water movement to the bow 12, tanks 40 and 42, and watertight engine room 36, assisting the forward section of the ferry 10 in flotation. If the tanks 38a and 38b fill to capacity, some water may rest on the aft portion of the deck 30, but the flotation provided by the tanks 40 and 42, watertight engine room 36, and the forward section of the ferry 10 will counteract the inflow and will eventually force a generally stable water level on the aft of the deck 30.
In addition, four deck water release doors 130, 132, 134, and 136 are incorporated, provided fore and aft on both vehicle decks 28 and 30 along one side of the ferry 10. In the event that hull breach results in a very significant inflow of external water that quickly fills the tanks 38a and 38b and begins to proceed up the vehicle decks 28 and 30, deck water release doors 130, 132, 134, and 136 can be employed to release water back into the ocean, sea, etc. to prevent the possibility of instability and capsize.
A bow fast water intake door 140 is also incorporated, controlled from the bridge 32. In the event that major hull damage occurs at the bow 12 above the lower vehicle deck 30,.allowing a large volume of external water to enter the vehicle deck areas quickly and removing the possibility of countering by lowering the stern 14, the bow fast water intake door 140 can be employed to provide ballast to the lower section of the bow 12 and prevent instability and capsize, the aft section of the ferry 10, various tanks, and watertight engine room 36 providing flotation.
However, whenever possible, the captain should attempt to provide an incline to stern to keep the propellers and rudder well into the water to allow for more effective control of the ferry 10.
Inclusion of watertight compartments 142, 144, and 146 will limit external water introduction to a given location within the vessel structure, and accordingly limit the impact of external water entry.
Once the ferry 10 has been stabilized, extra pumps can be brought in by service ships or helicopters to place on board the ferry 10 and assist the ship's pumps in removing the external water, particularly in the event that there is seepage around the watertight or semi-watertight doors.
It will be clear to any person skilled in the art that modifications of and adjustments to this invention, not shown, are possible without departing from the spirit of the invention as demonstrated through this preferred embodiment, as is the use of the present invention or variants with other types of water craft to delay or prevent sinking after hull damage.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, according to a preferred embodiment of the invention:
Figure la is a cross-sectional view of a standard ferry from port to starboard, showing water trapped in the watertight decks Figure 1b is a cross-sectional view of a standard ferry from port to starboard, showing water trapped in the watertight decks and the resultant capsize;
Figure 1c is a cross-sectional view of a ferry from port to starboard that takes incoming water into the lower stern of the vessel to maintain an even keel and prevent capsize Figure 2 is a cross-sectional port view of the present invention from bow to stern;
Figure 3 is a cross-sectional port view of the present invention from bow to stern demonstrating how controlled water intake raises the damaged portion of the ferry out of the water;
Figure 4 is a cross-sectional plan view of the present invention demonstrating the placement of the four ballast tanks, the watertight engine room, and the forward watertight compartments; and Figure 5 is a detailed cross-sectional view of the grating and fire damper arrangement.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now in detail to the Figures, Figure la shows upper and lower vehicle decks 28 and 30, the weight of vehicles, and most of the ship superstructure as normally positioned above the water line 70. As a result, the ferry is highly unstable when water 72 is introduced to the watertight decks as the result of hull or door damage. As shown in Figures 1a and 1b, the ferry may list due to the weight of vehicles, the water within the watertight decks, and the ferry superstructure, and the movement of the water back and forth within the watertight vehicle decks will increase the risk of capsize.
The ferry stabilization apparatus shown in Figures 2 to 5 is a preferred embodiment of the invention, comprising a system of ballast tanks 38a, 38b, 40, and 42 and means for directing water from inside and outside a ferry 10 into the ballast tanks, whereby a damaged section 24 of the ferry 10 is raised above the water line 70.
The bow 12 of the ferry 10 incorporates a loading door 22 in order to load and unload vehicles or other cargo (not shown) as desired, in a manner standard in ferries of the type. Vehicles are loaded onto the upper vehicle deck 28 and lower vehicle deck 30, and unloaded therefrom upon reaching their destination.
Vehicles can also be loaded and unloaded using a stern door 100.
The movement of the ferry 10 is controlled from within a bridge 32, and an engine room 36 is watertight and located toward the stern 14 of the ferry 10. Movement between the various areas of the ferry 10 is facilitated by means of passage sections 112, which may incorporate stairs, elevators, and/or passageways, including watertight or semi-watertight doors.
As can be seen by reference to Figure 4, stern ballast tanks 38a and 38b are situated in the stern 14 of the ferry 10. The starboard ballast tank 40 and port ballast tank 42 are located, respectively, in the starboard 16 and port 18 of the lower section of the ferry 10, to each side of the watertight engine room 36. The lower section of the ferry 10 forward of the watertight engine room 36 is divided into three watertight compartments 142, 144, and 146. The stern ballast tanks 38a and 38b are fitted with stern fast water intake doors 46a and 46b, respectively, to allow for water from outside the hull of the ferry 10 to enter the stern ballast tanks 38a and 38b, and are also fitted with air vents 62 to allow for the escape of displaced air within the stern ballast tanks 38a and 38b upon the entry of water. The starboard ballast tank 40 and port ballast tank 42 are fitted with air vents 62. Intake door controls 76 are located within the bridge 32.
The upper vehicle deck 28 and lower vehicle deck 30 are each fitted with a ballast tank grating 60 to allow for water held on the upper vehicle deck 28 and lower vehicle deck 30 to be directed into the stern ballast tanks 38a and 38b. The water passes into the stern ballast tanks 38a and 38b through the opening of fire rated dampers 68 which are situated beneath the ballast tank grating 60. As can be seen in Figure 5, the upper ends of the fire rated dampers 68 are attached to a deck 30 by means of hinges 116. Structural beams 120 are spaced as required to support the deck 30 and its load of vehicles. The structural beam 120, which supports the grating 60, also supports steel hangers 119 which in turn support the platform 69. The fire rated dampers 68 are normally in a closed position, their lower ends in contact with the platform 69 due to the action of hydraulic cylinders 148a and 148b. The hydraulic cylinders 148a and 148b are designed to control the opening and closing of fire rated dampers 68. Water passes through the grating 60 and collects on the platform 69, and the hydraulic cylinders 148a and 148b are employed to open fire rated dampers 68 and allow water to pass into the stern ballast tanks 38a and 38b and to close the fire rated dampers 68 when water ceases to flow through the grating 60, preventing water in the stern ballast tanks 38a and 38b from being reintroduced to the deck 30. Controls 108 (see Figures 2 and 3) are located adjacent the hydraulic cylinders 148a and 148b so that the ~ter~~ ballast tanks 38a and 38b can be left empty or filled to any desired level, with additional master controls 109 (not shown) on the bridge 32.
The water level in the bow 12 of the ferry 10 is monitored by means of loading door television cameras 26, with bridge television monitors 34 located on the bridge 32. The water level in the stern ballast tanks 38a and 38b, starboard ballast tank 40, and port ballast tank 42 is monitored by means of ballast tank television cameras 44 which are trained on water level markings 114 on the tank sides, with bridge television monitors 34 located on the bridge 32.
Having fitted the ferry 10 with the ferry stabilization apparatus described above, the utility of the present invention becomes clear in the following situation. Objects in the water or heavy wave action can cause damage to the bow 12 or loading door 22 of the ferry 10, leading to water intake at the damaged section 24.
Wave action will increase the amount of external water coming in through the damaged section 24, so the captain of the ferry 10 should turn the bow 12 of the ferry 10 away from the wind and waves in order to decrease introduction of more external water.
Stern fast water intake doors 46a and 46b are opened fully, allowing for intake water to move rapidly into the stern ballast tanks 38a and 38b and displacing any air within the stern ballast tanks 38a and 38b through air vents 62. Since ferry designers would probably include beams, floors, and partitions inside the stern ballast tanks 38a and 38b for structural reasons, openings in the floors and partitions would be necessary for the passage of water, and the presence of these structural obstacles would hinder the rapid motion of water within the tanks.
The controlled introduction of intake water to the stern 14 of the ferry 10 by means of intake door controls 76, which are similar in operation to the controls used on submarines for fast water intake hatches, will cause the stern 14 to settle lower, resulting in a corresponding rise of the bow 12, which slows down or halts new external water entry at the damaged section 24 by raising the damaged section 24 above the water line 70. The ferry 10 will likely only need to be inclined to a maximum of 6 degrees off the level of the water line 70.
When required to maintain an even keel starboard to port, some of the water in the stern ballast tanks 38a and 38b can be moved into the starboard ballast tank 40 and port ballast tank 42 by means of vertically operated flood gates 102a and 102b, respectively. Where conditions are such that the ferry 10 is subject to rolling from side to side, similar amounts of water should be introduced to the stern ballast tanks 38a and 38b as the ferry 10 rolls alternately to port or starboard, assisting in maintaining an even keel. However, should an uneven amount of water accumulate in the stern ballast tank 38a or 38b, the extra water could be moved by means of flood gates 102a or 102b. Flood gate controls 106 are located on the bridge 32. Maintaining an even keel will enable the officers and crew to keep the ferry 10 afloat and operational longer, also increasing the possibility of a safe and orderly vessel abandonment by passengers on a passenger deck 20 into life boats 64, should this become necessary given the extent of vessel damage or the weather conditions. Holding the water in the lower section of the ferry rather than trapping it within upper and lower vehicle decks 28 and 30 helps prevent listing of the ferry 10 to starboard 16 or port 18.
The stern tank is divided into stern ballast tanks 38a and 38b by means of a stern tank divider 110. This division allows for more effective control of the water contained therein. The stern tank divider 110 is fitted with stern tank floodgates 104, which are controlled by flood gate controls 106. When the ferry 10 is rolling due to external conditions, stern tank floodgates 104, which are normally in an open position, can be closed to prevent ballast from surging back and forth from starboard to port, thereby considerably reducing the degree of roll.
The external water that has already entered the ferry 10 will need to be directed away from the bow 12 of the ferry 10 to allow for the rise of the bow 12 due to the settling of the stern 14.
For this purpose, gravity flow is employed. Water on the upper and lower vehicle decks 28 and 30, given the tilt to stern 14 due to the settling of the stern 14, will flow toward the stern 14.
The fire rated dampers 68 would open by use of the control 108 and activation of the hydraulic cylinders 148a and 148b, allowing for movement of the external water into the stern ballast tanks 38a and 38b. This assists in the settling of the stern 14. The system of grating and fire rated dampers could also be used on ferries incorporating inclined vehicle decks. The external water that has settled in the bow 12 of the ferry 10 moves into the stern ballast tanks 38a and 38b, and then into the starboard ballast tank 40 and port ballast tank 42. Loading door television cameras 26 and ballast tank television cameras 44 are used to monitor the movement of water within the ferry 10, with bridge television monitors 34 being located on the bridge 32.
In the event that damage occurs at some other section of the hull, the various empty ballast tanks and forward watertight compartments could act as flotation means, increasing the stability of the ferry 10. For example, where damage occurs to the front or midship area below the lower vehicle deck 30, that area would flood and act as ballast but other sections-specifically the area above the lower vehicle deck 30, tanks 38a, 38b, 40, and 42, and watertight engine room 36-would provide flotation for the ferry 10, promoting stability and maneuverability despite the incline to the bow 12. In the event of damage to the stern 14 above the lower vehicle deck 30, some external water would flow through the grating 60 and into the tanks 38a and 38b, settling the ferry 10 by the stern 14 and enabling an even keel, and preventing water movement to the bow 12, tanks 40 and 42, and watertight engine room 36, assisting the forward section of the ferry 10 in flotation. If the tanks 38a and 38b fill to capacity, some water may rest on the aft portion of the deck 30, but the flotation provided by the tanks 40 and 42, watertight engine room 36, and the forward section of the ferry 10 will counteract the inflow and will eventually force a generally stable water level on the aft of the deck 30.
In addition, four deck water release doors 130, 132, 134, and 136 are incorporated, provided fore and aft on both vehicle decks 28 and 30 along one side of the ferry 10. In the event that hull breach results in a very significant inflow of external water that quickly fills the tanks 38a and 38b and begins to proceed up the vehicle decks 28 and 30, deck water release doors 130, 132, 134, and 136 can be employed to release water back into the ocean, sea, etc. to prevent the possibility of instability and capsize.
A bow fast water intake door 140 is also incorporated, controlled from the bridge 32. In the event that major hull damage occurs at the bow 12 above the lower vehicle deck 30,.allowing a large volume of external water to enter the vehicle deck areas quickly and removing the possibility of countering by lowering the stern 14, the bow fast water intake door 140 can be employed to provide ballast to the lower section of the bow 12 and prevent instability and capsize, the aft section of the ferry 10, various tanks, and watertight engine room 36 providing flotation.
However, whenever possible, the captain should attempt to provide an incline to stern to keep the propellers and rudder well into the water to allow for more effective control of the ferry 10.
Inclusion of watertight compartments 142, 144, and 146 will limit external water introduction to a given location within the vessel structure, and accordingly limit the impact of external water entry.
Once the ferry 10 has been stabilized, extra pumps can be brought in by service ships or helicopters to place on board the ferry 10 and assist the ship's pumps in removing the external water, particularly in the event that there is seepage around the watertight or semi-watertight doors.
It will be clear to any person skilled in the art that modifications of and adjustments to this invention, not shown, are possible without departing from the spirit of the invention as demonstrated through this preferred embodiment, as is the use of the present invention or variants with other types of water craft to delay or prevent sinking after hull damage.
Claims (10)
1. An apparatus for stabilizing a damaged ferry, said ferry having a hull and a bow incorporating a loading door for loading and unloading vehicles to and from lower and upper vehicle decks, said bow or loading door or any other part of the hull above the lower vehicle deck being damaged and allowing external water introduction, said apparatus comprising means for directing intake water from outside the said ferry into lower stern ballast tanks, whereby the said damaged bow or loading door is raised above the water line by lowering the stern of the said ferry.
2. An apparatus as in claim 1 further comprising means for directing said intake water into port and starboard ballast tanks located in the stern of the said ferry to ensure an even keel and to assist in lowering the stern of the said ferry.
3. An apparatus as in claim 1 further comprising means for allowing said external water that has already entered the said ferry through the said damaged bow or loading door to flow across the vehicle decks by gravity into the said lower stern ballast tanks.
4. An apparatus as in claim 1 further comprising automatic means for controlling the introduction of the said intake water.
5. An apparatus as in claim 1 further comprising a watertight engine room located between the said port and starboard ballast tanks.
6. An apparatus as in claim 1 further comprising television cameras adjacent to the said loading door, the said lower stern ballast tanks, and the said port and starboard ballast tanks, and television monitors in the bridge of the said ferry, whereby visual monitoring of the introduction and flow of the said external water within the said ferry is enabled.
7. An apparatus as in claim 1 further comprising ballast tank grating and fast water intake doors, whereby the said intake water is directed into the said lower stern ballast tanks.
8. An apparatus as in claim 1 further comprising air vents, whereby air within the said lower stern ballast tanks and the said port and starboard ballast tanks is allowed to exit.
9. An apparatus as in claim 3 further comprising fire rated dampers.
10. An apparatus as in claim 9 further comprising hydraulic means for opening and closing the fire rated dampers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2354729 CA2354729A1 (en) | 2001-08-03 | 2001-08-03 | Apparatus for stabilizing a damaged ferry |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2354729 CA2354729A1 (en) | 2001-08-03 | 2001-08-03 | Apparatus for stabilizing a damaged ferry |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2354729A1 true CA2354729A1 (en) | 2003-02-03 |
Family
ID=4169669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2354729 Abandoned CA2354729A1 (en) | 2001-08-03 | 2001-08-03 | Apparatus for stabilizing a damaged ferry |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2354729A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105649461A (en) * | 2015-12-30 | 2016-06-08 | 王静 | Raising and laying down sensing system of ship bow door |
| EP2305555A4 (en) * | 2008-08-12 | 2017-01-11 | Mitsubishi Heavy Industries, Ltd. | Righting moment recovery apparatus for marine vessel, and automobile carrying vessel equipped with the same |
-
2001
- 2001-08-03 CA CA 2354729 patent/CA2354729A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2305555A4 (en) * | 2008-08-12 | 2017-01-11 | Mitsubishi Heavy Industries, Ltd. | Righting moment recovery apparatus for marine vessel, and automobile carrying vessel equipped with the same |
| CN105649461A (en) * | 2015-12-30 | 2016-06-08 | 王静 | Raising and laying down sensing system of ship bow door |
| CN105649461B (en) * | 2015-12-30 | 2017-09-12 | 王静 | Sensory perceptual system is put in rising for ships and light boats bow door |
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