History of the anchor
Until the beginning of the 19th century anchors were of imperfect manufacture, the means of effecting good and efficient welding being absent and the iron poor, whilst the arms, being straight, generally parted at the crown, when weighing from good holding-ground. A clerk in Plymouth Yard, named Pering, in the early part of that century (1813) introduced curved arms; and after 1852 the British admiralty anchor, under the direction of the Board, was supplied to H.M. ships, followed by Lieutenant ("afterwards Captain") Rodger's anchor. Rodger's anchor marked a great departure from the form of previous anchors. The arms were formed in one piece, and were pivoted at the crown on a bolt passing through the forked shank. The points or pees to the palms were blunt. This anchor had an excellent reputation amongst nautical men of that period, and by the committee on anchors, appointed by the British admiralty in 1852, it was placed second only to the anchor of Trotman.
Later came the self-canting and close-stowing Martin anchor, which, passing through successive improvements, became the improved Martin anchor made of forged iron. A projection in the center of the arms works in a recess at the hub of the shank; the vacancies outside the shank are filled by blocks bolted through on each side, and are flush with the side plates, which keep the flukes in position.
The introduction of cast steel in 1894 led to the improved Martin-Adelphi pattern, in which the crown and arms are cast in one, and, with the stock, are made of cast steel, the shank remaining of forged iron. A projection in the crown works in a recess (right image), and is secured in its place by a forged steel pin, fitted with a nut and washer, which passes through the crown and the heel of the shank.
Traditional climbing
When a climber has reached the top of a climb an anchor must be set up to allow the leader to bring up the seconder safely. An anchor has a number of different components which should be put together in a redundant way to make the anchors safe.In some cases a traditional climb may be too difficult or there might not be enough time to complete the climb before dark. The lead climber may decide to abort the climb (or "bail") and descend to the ground before reaching the top. To do this an anchor is set up mid-climb and whatever protection that is required to ensure a safe descent is left on the rock after the climbers abseil to the ground.A number of types of rock are climbed on each with a varying degree of suitability for traditional climbing. Some examples are sandstone, granite and limestone.