When the American Civil War broke out in 1861, Roach was thus already well prepared to take advantage of the huge demand for marine engines generated by the conflict. He began by contacting the shipbuilder William H. Webb, who had just secured a contract for the huge new ironclad . Webb's usual engine suppliers, the Morgan Iron Works and Novelty Iron Works, were heavily inundated with orders and unable to meet his needs. Webb was so relieved to find an alternative source of supply, he not only awarded the Dunderberg's engine contract to Roach, but also became guarantor for the higher line of credit Roach would need to re-equip his works for completing the job.Swann 1965. pp. 18–19.
