It is likely that the captains of slave ships kept accurate records of their voyages for a variety of reasons. One reason might have been to keep track of the number of slaves they were transporting, as well as their health and well-being. Accurate records would have also been important for logistical purposes, such as planning the route and duration of the voyage, and for keeping track of supplies and other necessities. Additionally, accurate records may have been important for financial reasons, such as documenting the cost of the voyage and the value of the slaves being transported. Finally, keeping accurate records would have been important for legal reasons, as the slave trade was a highly regulated and contentious issue.