The paddle steamer was built by William Denny from Dumbarton and equipped with a 30 HP side-balancing steam engine by David Napier.

But soon the advantages of the steamship were recognized, as it travelled regardless of the weather and only needed 2 hours and 45 minutes for the crossing, which began to be reflected in a growing number of passengers and volume of freight.

In August 1821, the Roy Rob met the oncoming sailing ships Lord Duncan and Prince Leopold on the way to Calais.

The successful use of the Roy Rob led to traditional parcel ships being replaced by steamers on many routes in a very short time.

[3] The French government was interested in acquiring the Rob Roy, but a British export ban on machinery prevented the ship's owners from selling.