HM Coastal Motor Boat 4 is the torpedo boat used when Lieutenant Augustus Agar earned a Victoria Cross for carrying out a raid on Soviet warships in Kronstadt and sinking the cruiser Oleg. It was one of a large series of small, fast, shallow draught Coastal Motor Boats used during the First World War. She was designed by John I. Thornycroft & Company of Hampton, England, ordered in January 1916, built by them and delivered that summer. Agar’s VC is held by the War Museum in London.