Researching what I could about the Forfarshire, I found the builders, Adamson and Borrie of Dundee. Adamson was the shipwright and Borrie the engine maker, and they had a partnership that built a series of steam ships through the early nineteenth century.
I found the plans of a similar ship to the Forfarshire, built by Adamson and Borrie, almost the same dimensions, built a year later in 1837, named the Sea Horse. Only difference seems to be that it was three masted instead of two masted. Interesting in that it shows the general arrangement of the ship, and where the deck houses were and the hatches and skylights and companionways which can give me some ideas for my ship. It would be unlikely that ships of a similar period from the same ship yard would have been that different.
Sea Horse sailed between Ireland the United Kingdom and later in life, in 1845 sailed to Australia and spent another ten years transporting miners for the Australian gold rush before disappearing from the registers in 1855