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.

Besides the strengthened hull for work in ice and the provision of air conditioning necessary for work in all climates, they had modifications particular for a scientific vessel: wet and dry laboratories; a survey chartroom and photographic darkroom; oceanographic winches for deep seawater analysis and coring; stabilisers and a bow thruster, which enabled the ship to maintain her position when stopped for scientific observations.

In the 80's and 90's, 'Hecla' and 'Hecate' were equipped to make Gravity Free Air Anomaly observations over the mid-Atlantic ridge for the US Department of Defence 'Nav Star' GPS constellation of satellites.

Being the first vessel of the conflict to be in the glare of the world media, she gained a high public profile out of proportion to her ambulance ship role.

In 1969, commanded by Captain David Haslam (who retired after 10 years as Hydrographer in 1985), she landed a party who hoisted the Union Flag on Rockall, which significantly extended the UK's territory.