Floating prisons known as ‘hulks’ were a regular site on the Thames in London between the late 18th century and mid-19th century, used to house convicts awaiting transportation to British penal colonies including in what is now Australia.

The ‘hulks’ were actually decommissioned warships, dismasted and repurposed for the purpose of housing prisoners.

The decision to use the former warships – some of which had a storied history – for such a purpose was initially seen as a temporary measure to ease overcrowding in the jails with an Act of Parliament in 1776 only authorising their use for two years.

But, despite rising concerns over conditions on the hulks, they remained in use until 1857 when the act finally expired for good. Some 8,000 convicts were housed upon them in the first 20 years alone.

The hulks were initially moored off Woolwich – the former East Indiaman Justitia and a former French Navy frigate Censor were among the first – and the convicts aboard them put to use working to improve the river and at Woolwich Arsenal and nearby docks. The hulks were also later positioned at sites including Limehouse and Deptford (and the idea of using hulks was also exported to colonies in Australia and the Caribbean).

The hulks were initially operated by private individuals under a government contract but from 1802 they were placed under the supervision of the Inspector of Hulks. Aaron Graham was first to hold the post while his successor John Capper, who was appointed Superintendent of Prisons and the Hulk Establishment in 1814, oversaw numerous reforms of the system. During Capper’s tenure, the use of private contractors was later phased out with the government assuming direct responsibility for the hulks.

Some hulks – like positioned at Limehouse – were used as “receiving hulks” where prisoners were initially sent for several days where they were inspected and issued clothing, blankets, and a mess kit. They were then sent to “convict hulks” where they were assigned to a mess and a work gang for the long-term. Other hulks were to serve specific purposes such as being a “hospital hulk” (there was also a hulk off Kent, the Bellerophon, which was specifically designated for boys).

Conditions on board the vessels were indeed appalling and disease spread quickly with mortality rates of 30 per cent not uncommon. Prisoners were kept chained when aboard and floggings handed out as punishment for any offences. Food and clothing were of poor quality.

Despite this, the hulks continued to be seen as a convenient means of housing convicts and, in 1841, there were still more than 3,500 convicts on board hulks in England. It was said that one ship – a second vessel named Justitia – housed as many as 700 convicts alone.

Following several government inquiries into the hulks and the construction of more prisons on land, the hulks were gradually decommissioned. But altogether, between  1776 and 1884, the British Government had converted more than 150 ships into hulks in both the UK and the colonies.