There is another way for swinging ''single point'' moorings but a little labour intensive in the abscence of heavy anchors in this day and age i have found this method quite substantial.<<<From a scrapyard you want 2 engine blocks with all additions stripped off, and out, cyl/head pistons etc etc leaving if possible the crankshaft and flywheel still in position, SPIRIT CLEAN AND PREASSURE WASH THEM THOROUGHLY. you then want 2 x 10ft lengths of substantial chain a decent ring and appropriate shackles, shackle 1 length of chain to each eng/block which will use a couple of feet on each one. shackle the free ends to the large ring, your ground gear is now complete, there should be about 15ft between your block/sinkers. shackle to the ring a substantial length of chain for your ''riser'' this needs to be apx 4-5ft longer than the hight of the highest tide, shackle on a TOP QUALITY SWIVEL, finish with whatever type of bridle blows your skirt up!!!!! the empty CLEAN blocks are better laid on their sides,either by digging them in or scrounging a bit of labour from one of the divers in the club. this way they will sink in mud or sand, I know it seems long winded but I never found concrete ''blocks'' trustworty. And ''mouse'' all shackles. hope this helps. Derek,V.