A channel, about 91m wide and having depths of over 18.3m, forms the inner entrance of Expedition Harbor, between the reefs fringing Wasp Point and Satellite Point. The channel passes about 91m N of the latter point.
Middle Reef, an extensive drying shoal, lies in the middle of the fairway, abreast of Devils Point. A channel, about 183m wide and having depths of 12.4m, leads between the SE end of Middle Reef and the reef fringing Edgecumbe Point.
A drying reef extends 0.2 mile SE from Foul Point, about 0.5 mile NE of Devils Point. A channel, about 183m wide with a least depth of 23.8m, leads between the SW end of this reef and the N end of Middle Reef.