Dartmouth is one of the quarantine ports of the channel. The harbour is much frequented by steamers, and the homeward bound Dutch ships, and those of other northern nations, which remain during the time the rivers of the continent are frozen up; and is also a port of refuge for ships caught in adverse gales when going up or down channel. […]

In the latter part of the fifteenth century means were first taken for the efficient protection of the town and harbour. King Edward IV. having covenanted to pay the men of Dartmouth £30. for ever, out of the customs of Exeter and Dartmouth, on condition of their building "a strong and mighty and defensive new tower," adjoining the castle, properly furnished with arms and artillery, and always to find a chain in length and strength to be lain across the mouth of the haven from one tower to the other. Remains of these old fortifications on each side of the river are still to be seen. At this time there was another defence on the opposite side of the river, called Kingswear Castle, part of which is still standing.

[Text may be taken from a different source or edition than that listed as the source by Somers Cocks.]