Wooden ships were limited in size and their hulls could be more easily penetrated than metal ships during war. Ironclad ships reduced the cost and risk of shipping by enabling larger ships that were more difficult to sink.
The first known ironclad warship was The Nemesis, built for the East India Company, in 1839. Soon, virtually all ships ー military and commercial ー were built from iron rather than wood. The Nemesis was used effectively in the opium wars.
Laird, the shipbuilder, formed his company specifically to build metal ships. Their first boat, launched in 1828, was an iron barge.
Laird was 50 when he went into shipbuilding and did not have relationships with other shipbuilders. Both his age and lack of collegiality with industry incumbents are thought to have contributed to his willingness to disrupt traditional shipbuilding.