The East Hampton Town Board will ask the Army Corps of Engineers to proceed with its “enhanced navigation” plan for the dredging and maintenance of the Montauk Harbor inlet. The plan will increase the depth of the inlet to 17 feet and will dig a “deposition basin,” essentially a trench, on the channel’s east side to collect sand that would otherwise allow dangerous shoaling to form. The $26 million fix will cost the town $801,000.