The designation DER indicated "Destroyer Escort Radar picket ship." DERs carried no armaments, but the cannon were left in place to retain their appearances ... WDE, 487, Coast Guard Destroyer Escort. DER, 387, Destroyer Escort Radar Picket ... HAVERFIELD was converted to a radar picket ship at the Philadelphia Navy ... Search 'Destroyer Escort, Radar Picket' on Google.com! ... Search 'International Classification of Ships by Type' on Google.com! ... Destroyer escorts were also considerably more seaworthy than Corvettes. Destroyer escorts were also useful for coastal anti-submarine and radar picket ship ...