"like a hulk with two anchors"

A hulk is a ship that has been withdrawn from seafaring duty but can still perform a useful function, for example as a hospital or naval barracks. Wooden ships were often hulked when the hull structure became too old and weak to withstand the stresses of sailing; in the days of sail, many hulls served longer periods as hulks than they did as functional ships.

In Britain, hulks were often used as prison ships, particularly during the Georgian era when they provided a temporary solution to prison overcrowding. Hulks commonly held convicts awaiting transportation to penal colonies.

Two or more anchors were deployed on a floating hulk to prevent it shifting position with current or tide.

 

U.S. Navy ship of the line USS Vermont hulk (1898)
Public DomainU.S. Navy ship of the line USS Vermont hulk (1898) - Credit: Detroit Publishing Co.
The prison hulk Discovery at Deptford (c. 1824-1831)
Public DomainThe prison hulk Discovery at Deptford (c. 1824-1831) - Credit: Wikimedia Commons