Mountwood was launched by Mrs Hugh Platt on 6 July 1959 into the River Dart, and after being fitted out was delivered to the Mersey in 1960.

Upon the bridge deck, in the wheelhouse, one would find the large brass helm and steering pedestal, a binnacle, and two conjoined Chadburn Synchrostep engine order telegraphs.

The telegraphs were designed to give the captain direct control of the engines (although they could still be used in the traditional signal / response manner) and as such were marked with commands such as 'brake'and 'start'.

In her early years Mountwood was an unreliable ship, breaking down several times whilst crossing the river and having to anchor.

In 2001, the Mountwood was withdrawn and taken to Birkenhead's former Cammell Laird shipyard (which became owned by A&P), and then to Clarence graving docks, where she was stripped of her fittings and parts of her superstructure were removed and rebuilt.

Noticeable changes were the addition of a new, angle fronted, large wheelhouse and bridge deck, plus her funnel, which was reinstated after the refit, was moved further back to fit with the position of the new engines.

The vessels original helm and central binnacle were reinstated and some of the other bridge items are now in Mersey Ferries' collection.

In May 2011 the ferry's nameplate was replaced and it now carried the words 'Royal Iris' in Birkenhead Corporation style script font.

Royal Iris of the Mersey is a regular vessel used on both cross-river ferry services and also Manchester ship canal cruises.

The ferry still retains many features from her days as Mountwood including the original pair of Kockums Supertyfon fog horns, as does her sister ship.

On 10 July 2016, she unfortunately struck an underwater obstruction and took on water whilst waiting for another vessel to leave the entrance to the Manchester Ship Canal.