Second World War Extended Defence Officer's Post, Beacon Hill Fort (EHER 82276)

An Extended Defence Officer's Post (EXDO) used for marine minefield control during the Second World War comprising an irregular pentagonal concrete structure and built over an earlier pillbox.

Information from NRHE Extended Defence Officer's (EXDO) post for marine minefield control during the Second World War. An irregular pentagonal concrete structure situated on the tip of the Beacon Hill promontory, looking out along the breakwater and across the Stour/Orwell estuary. It has sides of 5.88m, 4.86m, 3.35m, 3.91m and 4.25m and is built precisely over an earlier pillbox, which was adapted and remained in use. A narrow entrance provides access to both parts of the structure; the pillbox down a small shaft with iron ladder. It has embrasures for both Bren light machine guns and smaller arms. The EXDO has two rooms, a main room for communications and charts and a smaller crew duty room. The former has a large observation embrasure with remains of painted calibration marks on its lower surface. Projecting from its ceiling is a small concrete turret, 0.91m square internally, with another observation embrasure. Surveyed at 1:500 scale by the RCHME in February 1997 as part of the Beacon Hill Fort Survey. EXDO posts were manned by a naval officers and other ranks concerned with the control of marine minefields, in this case protecting Harwich harbour. <1> An Extended Defence Officers Post (XDO) controlling a marine minefield built precisely over an earlier pillbox. In pan it is an irregular pentagon with sides of 5,88m, 4.86m, 3.35m, 3.91m, and 4.25m. Concrete is used throughout, and there are patches of external rendering. The structure was probably originally camouflaged. The pillbox was designed to be reached from ground level, but is now accessed by a narrow passage at the rear of the XDO from which a ladder descends 1.77m to the original pillbox entrance passage. The XDO post has a main room (communications/chart room) with a smaller room off the NE side. A prominent observation embrasure, 0.60m high, was shortened for operational reasons. It has an external overhanging canopy and internal metal brackets for top-hinged shutters. The remains of painted calibration markers survive on the lower surface of the embrasure. Projecting from the ceiling on the NW side is a small turret, 0.91m square internally, with its own observation embrasure. [see Report for further details]. Location: Beacon Hill Fort, Harwich <2> Additional references <3> - <7>