Invertible trawl door with resilient edge and adjustable ballasting

Claim 1

A TRAWL DOOR COMPRISING A BODY INTENDED TO BE UPRIGHT IN USE AND TO RIDE ALONG ITS LOWER EDGE UPON THE BOTTOM, MEANS FOR SECUREMENT OF A TOWING WARP TO SAID BODY, AND MEANS FOR SECUREMENT OF SWEEPLINE MEANS TO SAID BODY, TO DISPOSE IT AT A GIVEN ANGLE OF ATTACK, IN USE, AN EDGING OF RESILIENT, RUBBER-LIKE MATERIAL HAVING HIGH EXTENSIBILITY AND FORCIBLE QUICK RETRACTION, SUCH RUBBERLIKE EDGING BEING SECURED ABOUT SAID BODY AND BEARING AT ITS LOWER PORTION UPON THE BOTTOM, OR ALTERNATIVELY A ITS ORIGINALLY UPPER PORTION UPON REVERSAL OF THE DOOR TOP FOR BOTTOM, AND A BALLAST WEIGHT REMOVABLY SECURED ALONG AND ABOVE THE EDGE WHICH IS LOWAER, TO BALLAST THE DOOR INTO ITS UPRIGHT POSITION, IN USE, AND BY ITS POSITIONS TO BE PROTECTED AGAINST WEAR.