Safety regulation at sea deck load laws and the 19th century timber trade

In 1839, the British parliament passed legislation restricting ships from carrying cargo on deck (called deck loads) because deck loads were believed to substantially increase losses of both ships and seamen. This early case of safety legislation was repealed in 1862. The restrictions may well have been ineffective because of substitution into other risky activities by sailing vessels. Without deck loads, crews might have been smaller or more careless, and other safety measures might not have been used. Moreover, deck loads may have been replaced with other means of earning higher revenues that were more dangerous. I examine the effectiveness of deck load legislation with data from 1850 to 1872, covering both the period when the legislation was in effect and the period after repeal, and conclude the legislation had the perverse effect of increasing losses at sea.