Working Anchor size formula is 6.8 x the displacement in tons. Tons are long tons which are 2240 lbs. Storm anchors should be 1.35 x the weight of the working anchor. Anchor chain should be ISO proof coil for no windlass and ISO BBB coil if you have a windlass. The links are shorter and wrap around the drum better. Anchor rode 3 strand nylon diameter should be 0.2 + Anchor wt in lbs divided by 185. A windlass should have pulling power of 3 times the combined weight of the rode and chain.