(Per Norfolk Dredging): The main navigation channel is open to all traffic on Marcus Hook Range. The Dredge Essex is working in the upper end of MHA and vessels should avoid that area. The lower end of MHA is open to 1 vessel anchored at a time, with a 12 hour limit, per USCG. Any vessel transiting the area should contact the Dredge Essex on VHF Ch 13, 45 minutes in advance.