Sea anchor or changeable drag

Abstract

A device of the nature of a sea-anchor has a body tapered to the nose where it is attachable to a cable from a boat and formed with ports normally closed by spring-loaded closures but opened, by predetermined cable tension, to increase resistance to passage through water. Tail fins behind the body, and water passages through the body restrict rotation of the device. A chamber in the body when air-filled converts the device to a distress buoy, the tail fins uppermost to serve as a radar reflector, aerial for a distress transmitter in the body and carrier for a light.

I claim: 
     
       1. A sea-anchor or like device including: a hollow body,   attachment means, movable longitudinally in relation to the body for attaching a hawser to the body,   a plurality of ports formed in the body,   closures for the ports,   spring-loading means urging the closures to closed position, and   actuating means so connecting the attachment means to the closures that, upon the application of predetermined tension through a hawser to the attachment means, the closures are moved to open position against the action of the spring-loading means to increase the resistance of the body to passage through water.   
     
     
       2. A sea-anchor or like device according to claim 1 wherein: the attachment means is on the fore-end of a shaft slidable in the body, and   the actuating means includes links connecting the shaft to the closures.   
     
     
       3. A sea-anchor or like device according to claim 1 wherein: the body has a substantially conical front part tapering to the front and a substantially frustoconical rear part tapering towards the rear,   the ports are formed in substantially equally spaced arrangement in the body front part, each tapering towards its front, and   the closures are hinged at their fronts to the body front part for hinged movement into the body.   
     
     
       4. A sea-anchor or like device according to claim 1 wherein: an assembly of fins is mounted behind the rear of the body, and   a plurality of water flow-through passages are formed through the body from its front part to its rear.   
     
     
       5. A sea-anchor or like device according to claim 4 wherein: a chamber within the rear part of the body may, by the introduction of air, be made a buoyancy chamber for bringing the body, in water, to an upright position, its assembly of fins uppermost, and   the assembly of fins serves as an aerial for a radio distress signal transmitter within the body.   
     
     
       6. A sea-anchor or like device according to claim 5 wherein: means are provided for mounting a signal light on the assembly of fins. .Iadd.7. A sea anchor or like device comprising:   a hollow body having front and rear parts, each of which has a forward and rear end,   attachment means for attaching a line to the forward end of said front part for towing the body in a forward direction,   said front part of said body having an outer surface which converges toward its forward end, and said rear part of said body having an outer surface which converges towards its rear end,   a plurality of ports formed in said body for admission of water to the interior of the body, and   at least one outlet in said body for permitting escape of water from the interior of the body..Iaddend. .Iadd.8. A sea anchor or like device as claimed in claim 7 wherein said outer surface of said front part is generally conical, and said outer surface of said rear part is generally frustoconical..Iaddend. .Iadd.9. A sea anchor or like device as claimed in claim 8 wherein said ports are located adjacent to said front end of said rear part of the body..Iaddend. .Iadd.10. A sea anchor or like device as claimed in claim 9 wherein said ports are equidistantly spaced about the periphery of the body..Iaddend. .Iadd.11. A sea anchor or like device as claimed in claim 7, further including fins to resist rotation of the body..Iaddend. .Iadd.12. A sea anchor or like device as claimed in claim 7 wherein said at least one outlet is located in said rear part of the   
     
     
        body..Iaddend. .Iadd.13.  A sea anchor or like device comprising: a hollow body having front and rear parts, said each of which includes a forward end and a rear end,   attachment means for attaching a line to the forward end of said front part for towing the body in a forward direction,   said front part tapering radially outwardly from its front end, said rear part tapering radially inwardly from its front end in a direction opposite to said forward direction,   a plurality of ports for admission of water to the interior of the body, and   at least one outlet in the body for permitting escape of water from the interior of the body..Iaddend.