Duck Island Roads is a ruthless test of anchoring. Nasty mix of weeds and scoured hard, hard sand.
Back in the 70s, when my parents had a Pearson 30 and cruised between NYC and Marblehead every summer, we used a 12H, and never had a problem. A 20 would seem more than adequate. (but of course, your milage may vary)
As Feriation has observed, scope is your friend. Also remember that with a Danforth, getting the anchor dug in is vital, so backing down is also your friend, especially in areas with dubious holding ground.
Of course, anchoring isn't in our racing kit bag, except in foul current an no breeze, so I'm somewhat out of practice :-)
- David
