EP0145148B1 - Flotation bag assembly - Google Patents
Flotation bag assembly Download PDFInfo
- Publication number
- EP0145148B1 EP0145148B1 EP84306473A EP84306473A EP0145148B1 EP 0145148 B1 EP0145148 B1 EP 0145148B1 EP 84306473 A EP84306473 A EP 84306473A EP 84306473 A EP84306473 A EP 84306473A EP 0145148 B1 EP0145148 B1 EP 0145148B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- buoyant member
- payload
- compartment
- bag
- fluid medium
- 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.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B22/00—Buoys
- B63B22/18—Buoys having means to control attitude or position, e.g. reaction surfaces or tether
Definitions
- Objects of this invention are to make it possible to provide an apparatus for the stable support of a structure, such as an antenna, in a fluid medium, such as water; to limit the motion of an antenna supported above the surface of the ocean, within the operational limits of the transmitting system; and to support an electronics payload near the surface of the ocean such that the power loss between the electronics payload and an antenna supported on the surface is within operational limits and, specifically, less than 3db.
- Compartments 5a-5h act as containers for the fluid medium. Fluid encroaching upon bag 1 can enter the compartments through hole 6 or the opened top 7 and can drain from the compartments through the hole 6. When bag 1 rises due to the motion of the ocean, sea water will drain out of the holes 6, dissipating the kinetic energy of bag 1 created by the rising motion of the ocean. Oscillations of the flotation bag 1 within the medium W are thereby damped.
- the compartments increase the resistance to motion of damper skirt 4 by partially enclosing the fluid and by requiring the damper skirt to lift the partially enclosed fluid in the compartments as the flotation bag 1 rises in response to a wave. This acts to further decrease the heave and pitch of the flotation bag.
- this particular embodiment describes a flotation bag with a concave bottom
- the invention is meant to cover flotation devices of any material with a bottom of inwardly arched shape.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Hydrogenated Pyridines (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Description
- This invention relates generally to a stable support for structures at or above the surface of a fluid medium and in particular to a communications buoy for use in the ocean.
- Many types of flotation devices exist with differing characterisitcs.
- Damper plates and toroid shaped flotation devices have been used to create buoys which are wave followers. For example, see Buoy Engineering, H.O. Berteaux, John and Sons, 1976 Pg. 212-213. These surface following buoys are subject to strong heave and pitch due to the motion of the ocean.
- A more stable buoy can be built by decreasing the cross section of the buoy at the water level. Such devices experience less heave. The mass of the buoy can also be distributed to create a righting moment. This will decrease the pitch.
- Further stability can be obtained by surface decoupling. A buoyant cylinder with a counterweight suspended from its bottom is a typical example, Berteaux, supra. Such spar buoys cannot have much reserve buoyancy and usually have a large draft. These factors mitigate the usefulness of these types of buoys in deep water.
- It is an object of this invention to provide a communications buoy having an antenna which uses the surface of the ocean as a ground plane; such buoy having structure which limits the antenna's motion with respect to the surface of the ocean to within 4 in (10 cm.) heave and 25⁰ pitch.
- It is another object of this invention to provide a stable buoy that can withstand ocean conditions up to and including
state 5. - The buoy according to the invention may be used as part of a search and rescue system for locating downed aircraft and ships in distress. Such buoys would be carried by vehicles and be deployed when needed. Their distress signal could be received by satellites and their position located.
- A buoy according to the invention could carry various other types of payloads or support various antenna structures as well. Other possible uses include oceanographic monitoring buoys and satellite linked sonobuoys.
- Objects of this invention are to make it possible to provide an apparatus for the stable support of a structure, such as an antenna, in a fluid medium, such as water; to limit the motion of an antenna supported above the surface of the ocean, within the operational limits of the transmitting system; and to support an electronics payload near the surface of the ocean such that the power loss between the electronics payload and an antenna supported on the surface is within operational limits and, specifically, less than 3db.
- US-A-3500209 describes apparatus for the substantially stable support of a device in a fluid medium, said apparatus including:
a buoyant member;
support means associated with the buoyant member for supporting the device to be supported; and
channel means comprising at least one compartment having an upper opening and a lower opening, said compartment being connected to a side wall of the buoyant member whereby fluid which encroaches upon the buoyant member due to any motion of the member relative to the surface of the fluid medium enters a said compartment and is channeled by that compartment back into the body of the fluid medium through the lower opening, such that kinetic energy of the buoyant member associated with said motion is dissipated as the fluid is channeled back. - The present invention is characterized in that:
said compartment is open at the top to provide said upper opening and the lower opening has a cross-sectional area less than the cross-sectional area of the corresponding upper opening; and
said compartment is connected to the buoyant member with said upper and lower openings respectively above and below the mean surface level of the fluid medium when the apparatus is floating therein. - An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
- Figure 1 is a side view of a communications bouy according to the invention deployed in water.
- Figure 2 is a side view of the bouy of Figure 1 with parts broken away to illustrate internal structure.
- Figure 3 is a perspective view of a communications bouy according to the invention in an undeployed state.
- Figure 4 is a top view of a flotation bag according to the invention.
- Figures 5a -5g are graphs illustrating the operational transmission requirements and the estimated performance of an antenna system according to the invention under varying conditions of heave and pitch.
- Referring to figures 1 and 2,
flotation bag 1 is an inflated balloon-like structure having a specific gravity less than the specific gravity of fluidmedium W. Bag 1 enclosesantenna 2 and supports apayload 3 below the surface of medium W. - Although this embodiment comprises
flotation bag 1 which enclosesantenna 2, the invention includes flotation devices of any type which support structures. - Figures 5a-5g compare the estimated
performance 102 of an antenna such asantenna 3 under varying conditions of heave and pitch with theoperational performance requirement 101 for successful transmission.Antenna 3 uses the surface of the fluid W as a ground plane. Heave and pitch disturb the relationship between the radiatingantenna 3 and the ground plane, changing the radiation pattern ofantenna 3. As shown bygraphs performance 102 ofantenna 3 crosses and falls below the operational performance requirements for successful transmission between certain points on the graphs. In summary, successful transmission is not achieved whenantenna 3 undergoes more than 4 ins (10 cms) heave or 25o pitch. The apparatus according to the invention limits the motion of the antenna relative to the ground plane to within 10 cms. heave and 25o pitch, under ocean conditions up tosea state 5. - A
damper skirt 4 extends around the base of theflotation bag 1 and is made of a semi-rigid material supported in a horizontal position byribbon fence 5. - When the apparatus is afloat,
damper skirt 4 is below the surface of the medium W. The weight of thepayload 3, the shape of the bottom of theflotation bag 1 and the bouyancy ofbag 1, which will be described in detail below, are configured so thatdamper skirt 4 is below the water line when the apparatus is stable. -
Damper skirt 4 increases the surface area in contact with the ocean, offering a surface which resists motion V within medium W. In order to rise or tip in response to a wave,damper skirt 4 must travel upwardly through the fluid. The resistance to upward movement ofshirt 4 is caused by the fluid above theskirt 4. The energy that would otherwise cause heave and pitch of theflotation bag 1 is dissipated by this resistance and any resulting movement ofskirt 4 within the medium W. - As shown particularly in figure 4,
ribbon fence 5 which supports thedamper skirt 4 is a series of contiguous compartments, 5a-5g.Damper skirt 4 acts as the base of thecompartments 5a-5g ofribbon fence 5 and the side 1s of theflotation bag 1 forms the back wall of the compartments. The walls of the compartments in the embodiment illustrated comprise a strip of semi-rigid material connected to the side of theflotation bag 1 at spaced apart points P. Theflotation bag 1,damper skirt 4 and the strip form the contiguous compartments, the combination of which is referred to herein asribbon fence 5. - Each
compartment 5a-5g has anopening 6 in the lower portion thereof, where the strip joins todamper skirt 4. The compartments have an openedtop 7. When stable in the ocean, thebottom hole 6, which has a cross section less than the opening at thetop 7, is beneath the level of the medium W. The water line on the flotation bag when the apparatus is at rest in the ocean is approximately at themidpoint 8 of the height of theribbon fence 5. -
Compartments 5a-5h act as containers for the fluid medium. Fluid encroaching uponbag 1 can enter the compartments throughhole 6 or the openedtop 7 and can drain from the compartments through thehole 6. Whenbag 1 rises due to the motion of the ocean, sea water will drain out of theholes 6, dissipating the kinetic energy ofbag 1 created by the rising motion of the ocean. Oscillations of theflotation bag 1 within the medium W are thereby damped. The compartments increase the resistance to motion ofdamper skirt 4 by partially enclosing the fluid and by requiring the damper skirt to lift the partially enclosed fluid in the compartments as theflotation bag 1 rises in response to a wave. This acts to further decrease the heave and pitch of the flotation bag. - The
damper skirt 4 andribbon fence 5 are described associated with each other, constructed from semi-rigid materials for the purpose of stabilizingflotation bag 1. However, thedamper skirt 4 may be a submerged plate and the means for channeling fluid that encroaches on the device. Such structures may be used separately or in combination to decrease both the heave and pitch of the device. -
Payload 3 compriseselectronics 31 enclosed in acylindrical housing 32.Housing 32 is connected to the bottom of theflotation bag 1 bynylon cord 8. One end ofnylon cord 8 connects to a point 8a within the housing, approximately one-quarter from the top of the housing and the other end connects to the center of the bottom of thebag 8b, atbulkhead 9, which is a rigid portion.Electrical wires 311 also pass from theelectronics 31 into thebulkhead 9. Beneath thebulkhead 9 is microphonicsbumper 91. -
Nylon cord 8 and the location of the connection between thehousing 32 and theflotation bag 1, at 8a and 8b, decouple the motion offlotation bag 1 fromhousing 32 such that, over a certain range, the motion ofbag 1 does not affect the motion ofcylindrical housing 32 and the motion ofcylindrical housing 32 does not affect the housing motion ofbag 1. The range of motion depends on the demensions of the decoupling apparatus including the diameter ofhousing 32 and the distance between the top ofhousing 32 andmicrophonic bumper 91. -
Housing 32 is free to swing like a pendulum until the top of the housing 32a collides with themicrophonic bumper 91. Similarly, theflotation bag 1 can freely pitch until thebumper 91 collides with the top of the housing 32a. - This allows for 10⁰ - 15⁰ of motion of the
payload 3, measured from the vertical, before contact between housing 32a andmicrophonic bumper 91.Bumper 91 absorbs some of the energy of any impact betweenbag 1 andpayload 3, decreasing the effect such impact would have on the heave and pitch of the flotation bag.Bumper 91 also protects the electrical wiring that feed to the antenna, preventing interruption or interference with the transmission of a message due to impacts between the housing 32a and thebulkhead 9 through whichwires 311 pass. - In the embodiment illustrated,
electronics 31 is close toantenna 2 in order to minimize the power loss due to transmission of a signal fromelectronics 31 toantenna 2 viacable 311. Preferably, the power loss is less than 3db. - The
upper portion 33, ofhousing 32, referred to herein as a collar, stores the entire flotation apparatus before it is deployed, as shown in Figure 3. After deployment, theupper portion 33 floods with water, throughholes 14 in its sides, as shown in Figures 1 and 2. The flooding reduces the buoyancy of thepayload 3 which results inpayload 3 pulling theflotation bag 1 into the water, ensuring that thedamper skirt 4 andbottom hole 6 ofribbon fence 5 are submerged. This increases the stability offlotation bag 1. - The flooding of
upper portion 33 results in the center of mass ofhousing 32 being lower in the medium W, increasing the period of oscillation ofhousing 32. This stabilizes the entire structure and decreases the heave and pitch offlotation bag 1. - The center of the bottom of the
flotation bag 1 is pulled upward bystraps 13 secured at 131, along the inside wall offlotation bag 1. This reduces the buoyancy ofbag 1, aiding in maintaining the necessary waterline abovedamper skirt 4 and at the midpoint ofribbon fence 5. Thebase 16 ofbag 1 is inwardly arched at itscenter 15 so that the greatest bouyant forces are located at the outer portions of thebag 1. This decreases the pitch of theflotation bag 1 by creating a longer torque arm which must be overcome for the flotation bag to rotate. This righting moment further aids in stabilizing the flotation bag. The adhesion caused by inwardlyarched center 15 between the surface of the bottom 16 of the bag and the fluid medium W also decreases the heave of the flotation bag. - Although this particular embodiment describes a flotation bag with a concave bottom, the invention is meant to cover flotation devices of any material with a bottom of inwardly arched shape.
- The apparatus and payload are ejected in the
cylindrical housing 3, as shown in Figure 3.Antenna 4,flotation bag 1,ribbon fence 5 anddamper skirt 4 are all stored inupper chamber 33 of thehousing 32.Housing 32, which is bouyant, floats to the surface of the ocean after being ejected. The flotation bag and antenna are then deployed and the preprogrammed messages are transmitted.
Claims (9)
- Apparatus for the substantially stable support of a device (2) in a fluid medium, said apparatus including:
a buoyant member (1);
support means associated with the buoyant member for supporting the device (2) to be supported; and
channel means (5) comprising at least one compartment (5a-5g) having an upper opening (7) and a lower opening (6), said compartment being connected to a side wall of the buoyant member (1) whereby fluid which encroaches upon the buoyant member due to any motion of the member relative to the surface of the fluid medium enters a said compartment (5a-5g) and is channeled by that compartment back into the body of the fluid medium through the lower opening (6), such that kinetic energy of the buoyant member associated with said motion is dissipated as the fluid is channeled back;
characterized in that:
said compartment (5a-5g) is open at the top to provide said upper opening (7) and the lower opening (6) has a cross-sectional area less than the cross-sectional area of the corresponding upper opening (7); and
said compartment is connected to the buoyant member (1) with said upper and lower openings (7,6) respectively above and below the mean surface level of the fluid medium when the apparatus is floating therein. - Apparatus according to claim 1 characterised by a damper member (4) extending generally horizontally beneath the buoyant member (1) and below the mean level of the fluid medium when the apparatus is afloat, whereby to impede vertical motion of the apparatus relative to the fluid medium.
- Apparatus according to claim 1 including a plurality of said compartments (5a-5g) surrounding said buoyant member (1), characterised by a damper skirt member (4) extending generally horizontally around said buoyant member (1) to form a base for each said compartment (5a-5g), the lower openings (6) being formed between said base and side walls of the compartments.
- Apparatus according to any one of claims 1 to 3 characterised by a payload (3) carried by and below said buoyant member (1), said payload (3) being connected to said buoyant member by decoupling means (8) operative to decouple motions of the payload and the buoyant member from one another over a given angular range.
- Apparatus according to claim 4 characterised in that said decoupling means is a flexible member (3) connected at an upper end (8b) to a rigid portion (9) of said buoyant member (1) and at a lower end to said payload (3), said flexible member extending through a collar (33) of a housing (32) of said payload, and in that said rigid portion (9) has a bumper (91) positioned to engage said collar (33) when relative angular movement between the rigid portion (9) and the payload housing (32) attains a predetermined angle.
- Apparatus according to claim 4 or claim 5 characterised in that said payload (3) has a housing (32) including a chamber (33) within which said buoyant member (1) is stored when the apparatus is in an undeployed state.
- Apparatus according to any one of claims 4 to 6 characterised in that said device to be supported is an antenna (2) supported by said support means of said buoyant member (1), in that said payload (3) includes an r.f. signal generator (31) and in that said generator is electrically connected to said antenna.
- Apparatus according to any one of the preceding claims characterised in that the under surface of the buoyant member (1) is substantially concave (15).
- Apparatus according to claim 8 characterised in that the buoyant member is a flotation bag (1) having internal straps (13) connected between the bag walls (131) and the central portion of the bottom of the bag (16) to pull the under surface upwardly into said substantially concave condition (15).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US56176583A | 1983-12-15 | 1983-12-15 | |
US561765 | 1983-12-15 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0145148A2 EP0145148A2 (en) | 1985-06-19 |
EP0145148A3 EP0145148A3 (en) | 1988-10-19 |
EP0145148B1 true EP0145148B1 (en) | 1992-03-11 |
Family
ID=24243359
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP84306473A Expired - Lifetime EP0145148B1 (en) | 1983-12-15 | 1984-09-21 | Flotation bag assembly |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0145148B1 (en) |
JP (1) | JPH0645355B2 (en) |
AU (1) | AU565744B2 (en) |
CA (1) | CA1219363A (en) |
NO (1) | NO167192C (en) |
NZ (1) | NZ209269A (en) |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2917755A (en) * | 1957-10-01 | 1959-12-22 | Peck Ralph | Floating lantern support |
GB1072883A (en) * | 1964-11-27 | 1967-06-21 | Burndept Electronics Ltd | Radio rescue beacon |
JPS445130Y1 (en) * | 1965-12-30 | 1969-02-25 | ||
US3377615A (en) * | 1966-04-25 | 1968-04-09 | Sparton Corp | Compliant suspension system |
FR2404413A1 (en) * | 1977-09-28 | 1979-04-27 | Seban Norbert | Inflatable mattresses etc. with internal and external ties - for modular assembly of pneumatic panels of controlled depth |
JPS59863Y2 (en) * | 1978-08-31 | 1984-01-11 | 沖電気工業株式会社 | underwater anchor |
US4383831A (en) * | 1978-09-05 | 1983-05-17 | Raytheon Company | Stabilized suspension system |
-
1984
- 1984-08-10 AU AU31823/84A patent/AU565744B2/en not_active Ceased
- 1984-08-17 NZ NZ209269A patent/NZ209269A/en unknown
- 1984-08-30 NO NO843450A patent/NO167192C/en unknown
- 1984-08-31 CA CA000462265A patent/CA1219363A/en not_active Expired
- 1984-09-21 EP EP84306473A patent/EP0145148B1/en not_active Expired - Lifetime
- 1984-11-08 JP JP59235944A patent/JPH0645355B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
NO167192B (en) | 1991-07-08 |
NZ209269A (en) | 1987-06-30 |
AU565744B2 (en) | 1987-09-24 |
NO167192C (en) | 1991-10-16 |
NO843450L (en) | 1985-06-17 |
AU3182384A (en) | 1985-06-20 |
EP0145148A3 (en) | 1988-10-19 |
JPH0645355B2 (en) | 1994-06-15 |
EP0145148A2 (en) | 1985-06-19 |
CA1219363A (en) | 1987-03-17 |
JPS60177278A (en) | 1985-09-11 |
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