Sorry for self-quoting. But we have a new data point!OK, we have an N=2! I went sailing this weekend and repeated the procedure. Same result: the water that dripped off the chain was a bit muddy but not a single clump in the links, until the very end, a foot or two before the anchor came up (and even there only very little). This would probably easy to get rid off, by letting'er swing a bit, as several have suggested.
This was in a different anchorage (within APG). However, N=2 is not exactly a huge number. And of course this is still the same season (fall) and RichH noted that the mud problems might be more acute in summer. May well be, have to wait for the new season.
I will continue to employ this procedure, though likely not many more times this year. Indeed, this one may well have been my last outing for 2016.
After a (too-long) winter on the hard, last weekend was my first outing for 2017: a night in Fairlee Creek again. Anchored with 60' of chain in a spot where the depth meter jumped between 5' and 9' (must have been a hole and some bumps there). I actually had all forgotten about this thread but after I pulled up the first 10' of chain, all the following links were full of 'baby poop' again. Fortunately I remembered my discovery from last year and enjoyed having a chance to repeat the experiment.
Went back smartly twice with ~2000 RPM, noticed the boat came to a nice stop and then drifted forward. Then pulled up the chain again and --drum roll!-- NO mud any more, until the very last foot of chain at the anchor. And of course the anchor (Delta) itself had a few pounds of mud on it. Water dripping off the chain was dirty but all I had to to do when the anchor was up was to throw two buckets of sea water on the deck and it was reasonably clean.
So, we have three out of three success stories right now.
To be continued!