The bottom of the pylon sits on a round 2" stainless steel trailer-hitch welded to a stainless steel plate fastened to the bottom, and is held down to the plate with extremely strong Spectra line. The weight of the chains up top also help to keep the station pinned down to the ball, and also serve as shock-absorbers during heavy seas and winds.Note the zinc bar welded to the bottom plate, and the grounding plate positioned vertically on the pylon (wiring inside runs up to a lightening arrestor at the very top of the pylon). Click image to enlarge.
Photo by Bernadette Charpentier