COLLAPSIBLE SEA ANCHOR OR DROGUE

Abstract: A collapsible sea anchor or drogue (50) having first and second hollow frusto-conical body parts (74, 80) which are made from strong flexible material, such as canvas. Four flexible lines (60, 62, 64, 66) connect the two body parts (74, 80) together and to a nose portion (52) to which a towing line can be connected. The sea anchor or drogue (50) is very effective in that the drag is large having regard to the diameter of the body parts (74, 80) and, moreover, it can be compactly stored when in a collapsed condition.

Description: COLLAPSIBLE SEA ANCHOR OR DROGUE This invention relates to an improved drogue or sea-anchor. A device of this general description is described and illustrated in United States Patent No. 4,969,413 and has a hollow rigid body for towing behind a vessel by a hawser connected to the leading end of the body. While this device functions satisfactorily there is a need for a device which can be compactly stored and is preferably lightweight. An object of the invention is to provide a collapsible sea anchor or drogue. According to the present invention there is provided a collapsible sea anchor or drogue comprising: a first body portion which in an operative position has a hollow frusto-conical shape; a second body portion which in an operative position has a hollow frusto-conical shape; towing line coupling means for coupling a towing line thereto; means for interconnecting the first body portion, the second body portion and the towing line coupling means such that the towing line coupling means is located forwardly of a narrower end of the first body portion and the second body portion is located adjacent to a wider end of the first body portion with a wider end of the second body located adjacent to said wider end of the first body; characterised in that at least one of said first and second body portions is collapsible when in a non-operative position. Preferably, both of said first and second body portions are collapsible when in non-operative positions. Preferably said first and second body portions are made from flexible material. Preferably the material comprises canvas or fabric. Embodiments of the invention are shown, by way of illustrative example only, i the accompanying drawings, wherein: Figure 1 is a perspective view of a preferred embodiment of the invention; Figure 2 is a fragmentary view of the embodiment of Figure 1; Figure 3 is a front view of the embodiment of Figure 1; Figure 4 is a fragmentary view of part of the embodiment of Figure 1; Figure 5 is a fragmentary view of an alternative embodiment; and Figure 6 is a fragmentary view of a further alternative embodiment. The drogue or sea anchor 50 of the invention includes a nose portion 52 whic has vanes formed in a cruciform form shape so as to function as a paravane. The nos portion can be fabricated or moulded from metal or plastics material. The portion 5 includes a triangular plate 54 which forms a vane which would normally lie in a vertica plane. The portion 52 includes laterally extending vanes 56 which would normally li in horizontal planes. The plate 54 includes an eyelet 58 to which a towing hawser (not shown) can be attached. Each of the laterally extending vanes 56 includes a number of eyelets 59 to which the hawser can be selectively attached so as to cause the sea anchor or drogue to track laterally from the towing point if desired. Extending rearwardly from the extremities of the vanes are four flexible lines 60, 62, 64 and 66. Figure 4 illustrates one technique for connecting the lines to the nose portion 52. In this arrangement the ends of the vanes include slots 67 through which the lines are looped and fastened by means of stitching 69 or other fastening means. In an alternative embodiment shown schematically in Figure 5 the front ends of the lines 60, 62, 64 and 66 could be spliced directly to an eyelet 65 to which the hawser is, in use, connected. The lines may comprise of webbing, metal cable or rope. The lines are connected to first, second and third rings 68, 70 and 72. The rings are preferably formed from stainless steel or galvanised steel. Alternatively the rings could be formed from rope, webbing or other flexible material. The diameter of the ring 68 relative to the ring 70 is chosen so that the lines 60, 62, 64 and 66 lie on a generally conical surface with the ring 68 approximately midway between the ring 70 and t eyelet 56. The rings 68 and 70 together with the lines form a support surface for a fi frusto-conical cover 74 formed of flexible sheet material. The cover 74 is connected the rings 68 and 70 and the lines by bonding and/or stitching. The material for the cov may comprise of canvas, flexible plastic sheet material or other strong flexible fabric The drogue or sea anchor includes a rear portion 76 which is generally frust conical in shape but having an oppositely directed taper to the forward part of the s anchor. In the illustrated arrangement, the rearward ends of the lines 60, 62, 64 and are connected to a small terminal ring 78. A second frusto-conical cover 80 is connect to and supported by the rings 72 and 78 and lines extending therebetween. The cover again can be made from canvas, sheet plastics material or other strong flexible fabri The cover 80 may include an end portion (not shown) which spans the ring 78 so as close the rear end of the sea anchor or alternatively an opening may be left through t ring 78. When the device of the invention is towed by means of a hawser coupled to t eyelet 58 or to one of the eyelets 59, water will enter the forward end of the cover 74 an then be ejected through water outlets 82 formed by the gap between the covers 74 an 80. A small proportion of the water will be discharged through the terminal ring 7 The drag which is created when the device of the invention is towed through the wat generally speaking depends upon the diameter of the device and the speed with which is towed. Generally speaking, for larger diameters and larger speeds the drag is greate With the device of the invention, the lateral discharge of water through the outlets 8 increases the effective diameter of the device because the water flowing past the devic must be further laterally displaced owing to the water discharging through the outlets 8 Thus, the passing water has increased speed and more turbulence owing to the effect the discharge through the openings 82. As indicated earlier, the effect of these facto is to provide a drag greater than that which would normally be obtained from conventional sea anchor or drogue of the same nominal diameter. Figure 6 illustrates a further modification of the invention. In this case t stabilising vanes are formed within the first cover 74. More particularly, Figure 6 sho four fabric panels 90, 92, 94 and 96 arranged in a generally cruciform shape and havi an axis which is concentric with the axis of the frusto-conical cover 74. The panels c be stitched together and to the adjacent edges of the cover 74 or directly to the lines 6 62, 64 and 66. When water enters the forward end of the cover 74 the panels wi function as guide vanes to keep the sea anchor or drogue tracking in a stable manne The nose of this device would normally be as shown in Figure 5. Alternatively a nos portion 52 with vanes could also be used in this arrangement. The provision of th panels within the cover 70 is advantageous because stabilising vanes can be provide without adding significantly to the bulk of the device because the panels can be folde flat when the device is not in use. In a further modified arrangement, the rear portion 76 of the sea anchor or drogu could be made as a hollow rigid body for instance of pressed metal or moulded plastic material which is connected to the lines 60, 62, 64 and 66 or otherwise connected to th forward cover 74. In this arrangement the nose portion 52; lines 60, 62, 64 and 66; cove 74 and rings 68 and 70 can conveniently be stored within the interior of the rear portio 76. Similarly the forward portion could also be made as a hollow rigid body. Thes arrangements are suited to uses where space is less critical. The drogue or sea anchor of the invention can be used to assist in stabilising a vessel under power running before a sea and also as a sea anchor for a vessel without power, or for a multi-hull sailing vessel in adverse weather conditions, when streamed from the windward side, to prevent lift of the windward hull and impart stability to the vessel. Because the device of the invention can be compactly stored, it is ideal for use in life boats, life rafts and racing yachts where the provision of lightweight and compact equipment is very important. A tripping line (not shown) could be incorporated in the device and this would function in the usual way. It would normally pass through an opening in the body 52, run externally of the device and be coupled to the ring 78. Pulling the line will collapse the device and make it easier to pull back to the towing vessel. A prototype device has been made and found to perform very well. The prototy has the following dimensions: diameter of ring 68: 36cm diameter of ring 72: 60cm diameter of ring 78: 7.5cm overall length: 170cm axial length of cover 74: 46cm axial length of cover 80: 53cm axial length of gap 82: 7.5cm These dimensions can be varied to suit requirements. The embodiments of the invention herein described and illustrated by way example only may be subject to many modifications of constructional detail and desi within the ambit of the invention.

Claims: CLAIMS: 1. A collapsible sea anchor or drogue (50) comprising: a first body portion (74) which in an operative position has a hollow frusto conical shape; a second body portion (80) which in an operative position has a hollow frusto conical shape; towing line coupling means (58,59,65) for coupling a towing line thereto; means (60,62,64,66) for interconnecting the first body portion, the second bod portion and the towing line coupling means such that the towing line coupling means i located forwardly of a narrower end of the first body portion and the second body portio is located adjacent to a wider end of the first body portion with a wider end of the secon body located adjacent to said wider end of the first body; characterised in that at least one of said first and second body portions i collapsible when in a non-operative position. 2. A sea anchor or drogue as claimed in claim 1 wherein both of said first an second body portions (74,80) are collapsible when in non-operative positions. 3. A sea anchor or drogue as claimed in claim 2 wherein said first and second bod portions (74,80) are made from flexible material. 4. A sea anchor or drogue as claimed in claim 3 wherein the material comprises canvas or fabric. 5. A sea anchor or drogue as claimed in any one of claims 1 to 4 wherein said means (60,62,64,66) for interconnecting comprises a plurality of flexible lines (60,62,64,66). 6. A sea anchor or drogue as claimed in any one of claims 1 to 5 including rings (68,70,72,78) located at the ends of the first and second body portions (74,76). 7. A sea anchor or drogue as claimed in any one of claims 1 to 6 wherein there i a gap between the wider ends of the first and second body portions, said gap definin water outlets (82) for discharging in use water generally laterally of the sea anchor o drogue. 8. A sea anchor or drogue as claimed in any one of claims 1 to 7 wherein th narrower end of the second body portion (76) is closed. 9. A sea anchor or drogue as claimed in any one of claims 1 to 8 including vane (54,56,90,92,94,96) for imparting directional stability to the sea anchor or drogue as i is towed through water. 10. A sea anchor or drogue as claimed in claim 9 wherein the vanes (54,56) ar located on a nose body (52) which incorporates said coupling means (58). 11. A sea anchor or drogue as claimed in claim 9 wherein vanes (90,92,94,96) ar located within the first body portion (74). 12. A sea anchor or drogue as claimed in claim 11 wherein the vanes are formed fro perpendicular panels of fabric (90,92,94,96) connected within the first body portion or th second body portion. 13. A sea anchor or drogue wherein said second body portion (76) comprises a non- collapsible body. AMENDED CLAIMS [received by the International Bureau on 12 May 1993 (12.05.93) new claim 2 added ; claims 2-13 amended and renumbered as claims 3-14 other claims unchanged (3 pages)] 1. A collapsible sea anchor or drogue (50) comprising: a first body portion (74) which in an operative position has a hollow frusto- conical shape; a second body portion (80) which in an operative position has a hollow frusto- conical shape; towing line coupling means (58,59,65) for coupling a towing line thereto; means (60,62,64,66) for interconnecting the first body portion, the second body portion and the towing line coupling means such that the towing line coupling means is located forwardly of a narrower end of the first body portion and the second body portion is located adjacent to a wider end of the first body portion with a wider end of the second body located adjacent to said wider end of the first body; characterised in that at least one of said first and second body portions is collapsible when in a non-operative position. 2. A collapsible sea anchor or drogue (50) comprising: a first body portion (74) which in an operative position is hollow and tapers towards a forward direction of the sea anchor or drogue; a second body portion (80) which in an operative position is hollow and tapers towards a rear direction of the sea anchor or drogue; towing line coupling means (58, 59, 65) for coupling a towing line to a forward part of the first body portion; means (60, 62, 64, 66) for interconnecting the first body portion, the second body portion and the towing line coupling means such that the towing line coupling means is located forwardly of a narrower end of the first body portion and the second body portion is located adjacent to a wider end of the first body portion with a wider end of the second body located adjacent to said wider end of the first body; characterized in that at least one of said first and second body portions is collapsible when in a non-operative position. 3. A sea anchor or drogue as claimed in claim 1 or 2 wherein both of said first an second body portions (74,80) are collapsible when in non-operative positions. 4. A sea anchor or drogue as claimed in claim 3 wherein said first and second bod portions (74,80) are made from flexible material. 5. A sea anchor or drogue as claimed in claim 4 wherein the material comprise canvas or fabric. 6. A sea anchor or drogue as claimed in any one of claims 1 to 5 wherein sai means (60,62,64,66) for interconnecting comprises a plurality of flexible line (60,62,64,66). 7. A sea anchor or drogue as claimed in any one of claims 1 to 6 including rings (68,70,72,78) located at the ends of the first and second body portions (74,76). 8. A sea anchor or drogue as claimed in any one of claims 1 to 7 wherein there is a gap between the wider ends of the first and second body portions, said gap defining water outlets (82) for discharging in use water generally laterally of the sea anchor or drogue. 9. A sea anchor or drogue as claimed in any one of claims 1 to 8 wherein the narrower end of the second body portion (76) is closed. 10. A sea anchor or drogue as claimed in any one of claims 1 to 9 including vanes (54,56,90,92,94,96) for imparting directional stability to the sea anchor or drogue as it is towed through water. 11. A sea anchor or drogue as claimed in claim 10 wherein the vanes (54,56) are located on a nose body (52) which incorporates said coupling means (58). 12. A sea anchor or drogue as claimed in claim 10 wherein vanes (90,92,94,96) a located within the first body portion (74). 13. A sea anchor or drogue as claimed in claim 12 wherein the vanes are formed fro perpendicular panels of fabric (90,92,94,96) connected within the first body portion or th second body portion. 14. A sea anchor or drogue as claimed in claim 1 or 2 wherein said second bod portion (76) comprises a non-collapsible body.

Inventors: ABERNETHY WILLIAM JOHN, ABERNETHY, WILLIAM, JOHN
Applicants: ABERNETHY WILLIAM JOHN, ABERNETHY, WILLIAM, JOHN
Application year: 1992
Main classification: B63B21
IPC codes: B63B21, B63B22