I would suggest picking up a mooring if one is to be found. I have anchored many times in Tashmoo and Cuttyhunk west of bouy#6. I agree it is you best bet if you need to anchor. The only two times I ever dragged anchor was in Tashmoo and the outer harbor at Cuttyhunk. The eel grass is pretty healthy and we had a squall sneak up both times after midnight. Lucky we dragged east and not north towards Pease Ledge. You should have seen the ball of mud my Mason Supreme pulled up the next morning.