pretty much all moorings are granite blocks although there are a few concrete moorings. Granite has a density of 2.8 g/cc. A three ton granite block has an effective weight of a 1.92 tons or 3,800 pounds. A 500 pound mushroom has an effective weight of about 435 lbs. I will stick with my heavy lump of granite. Besides, my bottom chain weighs more than 600 lbs.