[f. COFFER + DAM.]
1. Hydraulic Engineering. A water-tight enclosure used for obtaining a dry foundation for bridges, piers, etc.; usually constructed of two rows of piles with clay packed between them, extending above high-water mark; the water being pumped out so as to leave the enclosure dry. b. Also a water-tight structure fixed to a ship’s side, for making repairs below the water-line.
1736. N. Hawksmoor, Acc. Lond. Bridge, 26. The way he proposes to lay the foundation is with Coffer-dams.
1751. Labelye, Westm. Br., 49. Why could not the Foundations of the Piers have been laid by the Help of Coffer-dams…?
1776. G. Semple, Building in Water, 30. They have indeed, of late translated the Word Batterdeaux, and rendered it Coffer-dam, which I presume, is a Word or technical Term not used, nor even so much as known in the English Tongue before the Year 1734.
1862. Smiles, Engineers, III. 412. The piles had been driven, and the coffer-dams formed and puddled.
1890. Daily News, 28 Jan., 6/1. It was necessary to construct a coffer dam inside the ship, and after the external patching to fill this dam with cement.
fig. 1876. E. Jenkins, Queen’s Head, 10. No … substituting of modern iron bedsteads for the ancient and capacious coffer-dams wherein their ancestors used to bury themselves at night.
2. (See quots.)
1881. Advance (Chicago), 28 April, 271. A new absorbent … from the cocoanut fibre … called cofferdam, and will hold … from 12 to 14 times its own weight of water.
1885. Daily Tel., 27 May. It has been discovered … that a composition obtained from pulverised cocoanut cellulose has the … property, when penetrated by shot … of closing up instantaneously, so as to prevent the influx of water into a ship’s hold. The name of ‘cofferdam’ has been given to this preparation.
3. attrib., as coffer-dam work, work performed in, or by means of a coffer-dam.
1772. Hutton, Bridges, 93. This is coffer-dam work.
Hence Coffer-dam v. trans., to provide with a coffer-dam.
1884. Daily News, 19 Dec., 5/7. Unless the pier is immediately coffer-dammed and the masonry repaired.
