US3906565A

US3906565A - Drifting ocean buoy

Info

Publication number: US3906565A
Application number: US455778A
Authority: US
Inventors: William T Dorrance; Norman W Schofield
Original assignee: General Dynamics Corp
Current assignee: General Dynamics Corp
Priority date: 1974-03-28
Filing date: 1974-03-28
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23

Abstract

A drifting ocean buoy is described which utilizes a drag structure which follows the water mass of the ocean as it flows in the form of the ocean current, and which also has an aerodynamically shaped low wind drag mast to minimize wind induced errors in ocean current drift measurements; the drag structure also being stable and resistant to heaving (pitch and roll) so as to maintain a mast carried antenna above the water even at high sea states.

Description

[ 1 Sept. 23, 1975 rent, and

wind

g mast to minimize wind induced errors in ocean current drift measurements; the drag structure also (pitch and roll) enna above the 3,084,354 4/1963 Lunenschloss.....,........... 3,506,841 4/1970 Majkrzak........... 3,774,563 11/1973 Anderson et Primary Examiner-Trygve M. Blix Assistant ExaminerGrcg0ry W. OConnor Attorney, Agent, or FirmMartin Lukacher, Esq.

[57] ABSTRACT A drifting ocean buoy is described which utilizes a drag structure which follows the water mass of the ocean as it flows in the form of the ocean cur which also has an aerodynamically shaped low dra being stable and resistant to heaving so as to maintain a mast carried ant water even at high sea states.

17 Claims, 7 Drawing Figures DRIFTING OCEAN BUOY ajon; Norman W. Schofield, San Diego, both of Calif.

Assignee: General Dynamics Corporation, St.

Louis, Mo,

Filed: Mar. 28, 1974 Appl. No.: 455,778

9/8 R; 9/8'R Int. B63B 35/00 Field of Search........... 9/8 R; 73/170 A, 170 R; 116/124 B, 26; 325/116; 340/2; 114/.5 T

References Cited UNITED STATES PATENTS 3/1960 Murray........................... 325/116 X United States Patent [191 Dorrance et a1.

[75] inventors: William T. Dorrance, El C U atant Sept .23,1975 Sheet 1 of2 US Patent Sept. 23,1975 Sheet 2 of2 11 HU IU H Tilllhfilll llmvllll DRIFTING OCEAN BUOY The present invention relates to ocean buoys and particularly to an ocean buoy which drifts with ocean current for providing oceanographic information.

In contradistinction to ocean buoys heretofore proposed, which are designed to stay in a fixed geographic location, the buoy provided-by the invention will drift and follow the ocean current. It tracks the ocean current and has means for minimizing the effects of wind and wave in producing motion which might alter its course from the course of the ocean current. The drifting buoy is provided with navigational aids which provide measurements of position. The buoyniay also be provided with thermal sensors for measuring horizontal and/or vertical advection in the upper layers of the ocean. Communications systems are provided for transmitting (as by telemetering) these measurements to a base station, which may be ashore or afloat.

For a discussion of. types of buoys, and bouyant platforms which are designed to maintain their location, as for position marking, reference may be had to US. Pat. Nos. 2,402,143; 3,084,354; 3,369,516; 3,453,670; 3,500,783; 3,559,223; 3,590,406; and 3,649,948. Except for wind driven devices which are designed to be blown ashore (see British Patent 23,978 of 1908) stability rather than movement in buoys has been the principal design objective.

Accordingly, it is an object of this invention to provide improved apparatus for measuring the motion of ocean currents.

It is a further object of this invention to provide an improved buoy for tracking ocean currents, alone or for the purpose of measuring advection in the upper layers of the ocean, or for providing other oceanographic information.

It is a still further object of the invention to provide an improved buoy which followsthe water mass, viz., is dragged along with the ocean water as it flows.

It is a still further object of the invention to provide an improved drifting ocean buoy having a submerged structure which has optimal ocean current-following characteristics.

It is a still further object of the invention to provide an improved drifting ocean buoy which is stable, being resistant to heaving (viz., pitch and roll) even in rough seas.

It is a still further object of the present invention to provide an improved ocean buoy having low wind drag; thus minimizing ocean current course and positional errors due to wind effects.

It is a still further object of the invention to provide an improved drifting ocean buoy which is relatively low in cost such as to minimize economic loss if lost at sea.

Briefly described an, ocean buoy embodying the invention has a hull, a mast for carrying an antenna disposed above the hull and a drag structure disposed below the hull; the entire structurehaving buoyancy such that the mast and the upper portion of the hull rides above the waterline. The drag structure is a cylindrical tube, open at the bottom, and which is vented by holes distributed over its entire surface area. The tube may have longitudinal ribs spaced around its periphery. The ribs serve to both stiffen the structure and enhance its current-following characteristics. The ribs may be hollow and filled with buoyant material, e.g., plastic foam. A ballast ring may be disposed at the open end of the tubular body. The structure is optimally matched to the current in the ocean. and is dragged along by the current; thus following the current with a high degree of accuracy. Temperature sensors in the body can measure-ocean temperature so that advection in, and the heat budget of, the ocean may be plotted. The mast has an aerodynamic shape and a low wind drag profile. An antenna extends from the mast and is maintained above the water because of the stability imparted by the drag structure.

Electronic equipment coupled to the antenna includes navigational aids for providing data as to the geographic position of the buoy and provides for the communication of such data, as well as the sensor data, by radio transmission via the antenna to monitoring stations. 7

The foregoing and other objects and advantages of the invention will become more a'pparentfroma reading of the following description in connection with the accompanying drawings in which:

FIG. 1 is a perspective view ofa buoy, embodying the invention, deployed in the ocean;

FIG. 2 is, a more detailed elevational view of the buoy shown in FIG. 1;

FIG. 3 is a plan view of the buoy shown in FIG. 1;

FIG. 4 is a fragmentary end view showing the mast and hull of the buoy;

FIG. 5 is a sectional view along line 5-5 in FIG. 4 of the mast illustrating its aerodynamic, tear-drop-like shape and a spar used in its internal construction;

FIG. 6 is a sectional view, along line 6-6 in FIG. 2, of the drag structure; and

FIG. 7 is a fragmentary view of the bottom of the drag structure.

Referring more particularly to the drawings, FIG. 1 shows the buoy l0 deployed in the ocean 12. The principal components of the buoy 10 are a hull 14,v a mast 16 from which a whip antenna 18 extends, and a drag structure 20. The drag structure may suitably be 30 feet in length and 3 feet in diameter. The. hull may suitably be about 3 feet in length and 4 feet in diameter. The diameter of the hull may be increased to say 6 feet or 8 feet in diameter to allow a greater payload. The mast 16 may extend upwardly from the hull 14, about 10 feet with the antenna extending an. additional 7 feet above the top of the mast.

The drag structure may be constructed from separate sections which are assembled together as by clamping rings (not shown to simplify the illustration). Each section may suitably be about I0 feet in length. The mast 16 and the drag structure may be constructed from non-metallic material such as sheets of laminated glass fiber which are sold under the trade name Fiberglass.

The hull 14 may be constructed from steel or aluminum. By virtue of the construction of the buoy in principal part of non-metallic light-weight materials, a total weight of under 2,000 lbs. may be obtained, thus allowing the buoy to be easily stowed and handled.

Referring more particularly to FIGS. 2 through 7, it will be noted that the hull 14 has two

compartments

22 and 24, access to which may be obtained by way of a hatch 26. The lower compartment 24 may contain

cases

28 and 30 of batteries, which supply power to communication, navigation, data and sensor electronic systems which are located in a case 32 in the upper section 22 of the hull I4. The communications equipment may be a radio receiver and transmitter which is coupled to the antenna I8. The navigation system may be an omega receiver and computation unit which calculates the geographic position of the buoy from omega signals received by the antenna 18. These position signals are then re-transmitted by way of the transmitter and antenna 18 to monitoring stations which may be shore based or based on ships.

Sensors such as thermistors 21 for measuring water temperature may be located in the drag structure 20. It may be desirable also to mount air temperature and wind velocity sensors on the mast 16 which provide signals to the electronic systems in the casing 30. These systems may be termed data acquisition systems and may operate in accordance with conventional telemetry techniques to convert the temperature, wind velocity and other sensor outputs into digital signals which are transmitted by telemetry techniques over radio channels to the monitoring stations.

It will be noted that the water line is relatively high, say approximately 1 foot from the top of the hull; thus providing a low drag above water due to wind effects. The buoy has approximately neutral buoyancy such that it rides very low in the water as indicated in the drawing.

The mast 16 has an aerodynamic shape tapering upwardly to its narrower section near the top of the mast. The shape of the mast 16 is defined by spars 34 held in lateral position by a pipe 36 which extends through openings in the spars 34 and is attached thereto. This pipe 36 may be of aluminum. The spars and the mast are of drop-like shape in cross section to define an aerodynamic shape for the exterior surface or fairing of the mast 16, which is of non-metallic construction, such as being made out of fiberglass. The pipe 36 may be bolted to struts 38 which are fastened to the hull superstructure as by bolts (not shown). The antenna 18 is also held securely in place in the mast by extending through openings in the spars 34.

The drag structure 20 is a cylindrically tubular body made of non-metallic material such as glass fiber sheets 43 (e.g., Fiberglass) which are laminated together. These sheets 43 are shown in greater detail in FIG. 6. The bottom end 40 of the cylindrical body 20 is open such that the body 20 is filled with sea water. A ballast ring 42, say of steel, may be attached by steel angle iron 47, formed in the shape of a ring, to the bottom 40 of the body 20 for ballasting purposes.

A plurality of longitudinal ribs 44, which may be about twenty in number spaced at approximately equal lateral distances from each other, are located around the peripheral surface of the body 20. These ribs 44 are parallel to each other. They are also hemicylindrical in shape and define buoyant compartments 46 therein which may be filled with foam material, such as plastic foam, foam rubber, or the like. For a three-foot diameter body the ribs may have a radius of inch and may be formed out of the sheets 43 integrally with the sheets 43 out of which the body 20 itself is formed. These ribs 44 provide stiffening or bracing for the body 20 as well as improve its drag characteristics (viz., define a drag shape which closely couples to the ocean currents such that the buoy l drifts with the current).

A lattice of holes 48 is disposed around the entire surface area of the body and vents the body to the ambient ocean water. The holes 48 are disposed in columns between the ribs 44 with holes in adjacent columns laterally offset with respect to each other. The holes 48 together with the ribs provide a drag shape which closely couples to the current having a drag coefficient C which can exceed 1.2. In addition to the drag characteristics the drag structure 20 provides stability for the hull, thus assuring that the antenna will remain out of the water even in rough seas (viz., high sea states). The drag structure construction can readily be provided with the desired buoyancy by selecting the ballast ring 42 of a requisite weight; thus allowing the hull to ride very low in the water exposing minimum surface area to wind drag. In addition, the stiffening provided by the ribs 44 allows for minimal torsional drag; thus contributing to the close coupling between the drag structure and the ocean currents. The drag structure also assists in maintaining the buoy and mast in upright position minimizing any yaw due to the current. With yaw minimized and with the aerodynamic shape of the mast 16 providing minimal wind drag, positional errors which might otherwise move the buoy to some geographic location other than that due exclusively to the ocean current are minimized. The holes 48 which vent the drag structure 20 also reduce heaving (viz., pitch and roll) and contribute significantly to the stability of the buoy and its ability to maintain the antenna 18 out of the water at all times.

The herein described ocean buoy therefore is capable of accurately tracking ocean currents as well as providing information as from the temperature sensors disposed within the cylindrical body 20 so as to facilitate the measurement of both horizontal and vertical advection in the upper layers of the ocean in which the buoy is disposed.

From the foregoing description it will be apparent that there has been provided an improved ocean buoy and while a specific configuration with suitable dimensions and shape has been described in order to illustrate the invention, it will be appreciated that variations and modifications in the hereindescribed buoy within the scope of the invention will undoubtedly become apparent to those skilled in the art. Accordingly, the forego ing description should'be taken as illustrative and not in any limiting sense.

What is claimed is:

1. In an ocean buoy, a drag structure which is matched to the ocean current and is adapted to be dragged along and follow the current, said structure being adapted to be submerged below a floating hull, said structure comprising an elongated cylindrically tubular body having its upper end attached to said hull and being open at the end thereof opposite from said hull, said body having a plurality of holes distributed between the ends thereof over substantially the entire surface area thereof and extending through the walls of said body for venting said body for passage of water into and out of said body, a plurality of ribs disposed on the exterior of said body and extending longitudinally substantially the entire length thereof, said holes being located between adjacent ones of said ribs, said holes and said ribs providing a drag shape closely coupling and matching said structure to the ocean current.

2. The invention as set forth in claim 1 wherein said ribs define buoyant cavities therein.

3. The invention as set forth in claim 2 wherein said cavities contain buoyant material.

4. The invention as set forth in claim 2 including a ballast ring disposed at the open end of said body.

5. The invention as set forth in claim 1 wherein said body is a cylindrical tube much greater in length than in diameter, said holes are distributed in longitudinal columns along the entire length of said tube, the holes in adjacent columns being offset from each other.

6. A drifting ocean buoy for following ocean current which comprises a hull, a mast extending upwardly from said hull and a drag structure extending downwardly from said hull and adapted to be submerged to a depth much greater than the submergence depth of said hull,

said mast having a fairing tapering upwardly from larger to smaller cross sectional area, and being droplike in shape in cross-section whereby to present a low aerodynamic drag profile,

said drag structure being a cylindrical tubular body open at the bottom,

a plurality of holes distributed over the entire area of said tube for venting the interior thereof to the ocean water.

7. The invention as set forth in claim 6 including an antenna of rod-like shape extending upwardly through said mast.

8. The invention as set forth in claim 7 including electronic means for position location and communications coupled to said antenna.

9. The invention as set forth in claim 8 including sensor means for measuring water temperature coupled to said electronic means.

10. The invention as set forth in claim 8 wherein said body has a plurality of longitudinal ribs, disposed thereon in parallel spaced relationship.

11. The invention as set forth in claim 10 including buoyancy providing means disposed in said ribs, and ballast means disposed on said body, said buoyancy providing means and said ballast means providing approximately neutral buoyancy in said drag structure.

12. The invention as set forth in claim 10 wherein said mast has a fairing of non-metallic material.

13. The invention as set forth in claim 12 wherein said hull has a shell of metallic material.

14. The invention as set forth in claim 6 wherein said tubular body is of non-metallic material.

15. The invention as set forth in claim 12 wherein said material comprises sheets of compressed glass fibers.

16. The invention as set forth in claim 15 wherein said hull has a shell of compressed glass fibers.

17. The invention as set forth in claim 14 wherein said non-metallic material is compressed glass fibers.

Claims

6. A drifting ocean buoy for following ocean current which comprises a hull, a mast extending upwardly from said hull and a drag structure extending downwardly from said hull and adapted to be submerged to a depth much greater than the submergence depth of said hull, said mast having a fairing tapering upwardly from larger to smaller cross sectional area, and being droplike in shape in cross-section whereby to present a low aerodynamic drag profile, said drag structure being a cylindrical tubular body open at the bottom, a plurality of holes distributed over the entire area of said tube for venting the interior thereof to the ocean water.