Public Armed Ship Muirchú (Irish: [ˈmˠɪɾʲxuː]) was a ship in the service of Irish Free State's Coastal and Marine Service (CMS). She was the former Royal Navy ship HMY Helga and was involved in shelling Liberty Hall in Dublin from the River Liffey with her pair of 12-pounder naval guns during the Easter Rising of 1916. Helga was purchased by the Irish Free State in 1923 and renamed Muirchú (Irish: Hound of the Sea). She sank off the Wexford coast after disposal in 1947. The wheel was recovered from the wreck by local divers and can now be seen in Kehoes Pub in Kilmore Quay.