diameter of the support shaft 36 c immediately below the support shaft 36 c said first end 36 a of the lower rod 36 has an annular flange 36 h with a diameter that is also greater than the diameter of the support shaft 36 c the cylindrical plate 36 d and annular flange 36 h along with the support shaft 36 c which has a smaller diameter and is disposed solidly between said cylindrical plate 36 d and annular flange 36 h that are of greater diameters forms a locking groove 36 h that receives the first locking flange 26 a of the slide 26 the upper rod 34 of the hydrostatic release 10 also comprises a first end 34 a fig7 and a second end 34 b fig7 the first end 34 a of the upper rod 34 includes a necked flange 34 c that is comprised of a small preferably cylindrical support shaft 34 d supporting a centrally positioned cylindrical plate 34 e the diameter of the cylindrical plate 34 c is greater than the diameter of the support shaft 34 d likewise immediately below the support shaft 34 d said first end 34 a of the upper rod 34 has an annular flange 34 f with a diameter that is also greater than the diameter of the support shaft 34 d the support.