Hecla-class survey vessel
 The Hecla class formed the backbone of the Royal Navy's ocean survey fleet from the mid-1960s. Three ships HMS Hecla HMS Hecate and HMS Hydra were ordered in the early 1960s to replace the aging survey ships HMS Scott and HMS Shackleton.The hull design was based on that of the RRS Discovery and the Hecla class were built to commercial standards costing £1.25 million each.