[7] In 1862 Porcupine surveyed off the west coast of Ireland under the command of Richard Hoskyn in preparation for the laying of the replacement transatlantic telegraph cable.

Previous surveys had shown very steep descents at the edge of the continental shelf, but Hoskyn's work identified a suitable route to the west of Slyne Head.

[5]: 322  In 1869 she was chartered by the Royal Society to investigate the deep sea bed to the west of Ireland with the intention of looking for living organisms below 600 m depth.

The azoic theory of Edward Forbes hypothesised that life could not exist below this depth due to the great pressure.

The Porcupine Bank, an area of seabed to the west of Ireland partly detached from the continental shelf by a failed rift event, was discovered by this expedition and is named after this ship.