fascinating paper here.
British slave traders were early and rapid adopters of the new technique of sheathing ships' hulls with copper. From the 1780s this innovation increased sailing speeds of British slave ships by about a sixth, prolonged the ships' lives by at least a half, and reduced the death rates of slaves on the middle passage by about half. It was, above all, the fall in death rates, and possibly the improved condition of surviving slaves, that made the investment so compelling. Copper sheathing may have paid for itself in a single voyage, even though it was usually good for several. By the 1790s few slave ships, even if making only a single voyage, were uncoppered. These results confirm that copper sheathing was one of the major improvements in shipping productivity before the use of iron and steam in the mid-nineteenth century.
I am not sure if this would be really that appreciated by the slaves, what would you prefer? an agonising death on the slave ships or a life of slavery?
one thing which I have read about slave ships is how the British squadrons came to know about the slave ships. Besides intelligence and beating about the mouths of African rivers to capture the slavers, they used the power of smell. Slave ships were extremely odorous. truly disgusting, specially on the trans Atlantic voyages or up to Europe. first, the slaves would be chained down spoon fashion for the voyage. they would be crammed in tightly as a sardine in a can, with multiple decks. layer after layer after layer. they wouldn't be fed that frequently either. They will piss, shit, vomit, sweat, drip blood, die, all in the same area. if they were lucky,they were brought up to be given a drenching in the cold sea water, but no captain would risk a mutiny or rebellion so death rates of up to 50% were accepted.
so anything that reduced the voyage time, would help increase the survival rates…
here are some of the photographs from our visit to Portsmouth…you can see the photograph showing the shelf in which you as a slave will be curled up in chains for 2 weeks, the gaps in the wood will let all the bloody fluids and sewage from top drop on you.