This has been variously interpreted as a reference to a standing naval force, similar to those maintained by Aethelred the Unready against the Vikings, or to a service restricted to the ports of Kent and Sussex which developed into the organisation of the Cinque Ports of the later middle ages. In fact, the second passage, the Customs of Warwick (WAR B6), shows that the same service was demanded of at least one inland Borough. The entry records that:
The most natural interpretation of these two entries is that they refer to the arrangements for the payment of troops engaged in naval service, this being simply one aspect of the general military obligation of the late Anglo-Saxon period. There are similar references to the naval service of Barnstaple, Lydford and Totnes (DEV 1,2), and of Bedford (BDF B1), Exeter (DEV C5), Lewes (SUS 12,1), Romney (KEN 5,178), and Stamford (LIN S1). The Lewes entry states that the money was for 'those who had charge of arms in the ships', presumably meaning the armed men. Although almost all references to naval service relate to boroughs, two entries for Bishampton (WOR 2,21) and Somerby (LIN 57,43), imply that naval service was the naval dimension of the general military obligation laid upon all landowners. The service of several boroughs is specified as being 'by land or sea', and the obligation of Malmesbury shows that service at sea, like that on land, was based upon the 5-hide unit.
As with so many aspects of Domesday Book, the obligation to naval service in particular, and to military service in general, is another of those topics erratically recorded by the commissioners.
For discussion of this topic, see C. Warren Hollister, Anglo-Saxon military institutions on the eve of the Norman Conquest (1962) and The military organisation of Norman England (1965); Richard P. Abels, Lordship and military obligation in Anglo-Saxon England (1988); and Nicholas A. Hooper, 'Some observations on the navy in late Anglo-Saxon England', Studies in medieval history presented to R. Allen Brown, edited by C. Harper-Bill, C.J. Holdsworth and J.L. Nelson (1989), pages 203-13.
See also steersman.