The Early Development of Hatch Covers

Abstract

There is a Chinese proverb which runs: ‘Water can both float and sink a ship’; a literal reading of which encapsulates one of the central dilemmas faced by naval architects through the ages. In order to comply with the laws of hydrostatics, a ship must be arranged so that its hull is buoyant and keeps water out. Yet if it is to be more than a simple raft, a ship must be arranged to allow access to its interior. To be buoyant in all the conditions that it is likely to meet in service, the ideal hull would be a hollow, watertight chamber, yet to provide access it is necessary to destroy its watertight integrity by cutting openings in its shell. Throughout maritime history many solutions to this problem have been devised, but the number of fundamentally different ways of providing access to a ship is limited to three.