This thread prompted me to research the gound tackle topic a bit deeper also.
It appears to me that current generation anchors and recent tests are challenging conventional wisdom. Heavy chain and cantenary don’t help much unless you are in deep water so no need to carry the extra weight. Go with less and lighter HT chain. 100 ft of 1/4 inch G7 weighs 84 lbs and has a WLL of 3160 lbs., more than 5/16 in BBB. Spend the weight saving on a larger anchor.
Here is another: Nylon is the wrong rope for an anchor rode on a vessel our size. Too much stretch promotes yawing and chafing; internally generated heat robs line strength. Multi-plait polyester is preferable.
Steve Dashew, Morgans Cloud and Rocna Knowledge Base websites elaborate at length.
http://www.rocna.com/distributable/dashew-right-rode.pdf
http://www.morganscloud.com/techniques_tips/ttqaanchoring.htm
http://www.rocna.com/kb/Chain
I draw my own conclusions in a couple of recent entries on my blog.