Three masted vessel in the English Channel off Dover?

This watercolour depicts a three-masted vessel under full sail in starboard broadside view with white cliffs and additional vessels in the background. It is signed and dated lower right ‘WA Richards / 07’. ‘St Lawrence’ and ‘Lubbock’ are inscribed on the verso. This drawing was created as an illustration for Basil Lubbock’s ‘The Blackwall Frigates’ (Glasgow: James Brown & Sons, 1922), in which it appears opposite page 148. Lubbock’s book indicates that the drawing is intended to represent the ‘St Lawrence’ of 1861, built by T. & W. Smith at Newcastle-upon-Tyne.