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.
Ghogha
The stone anchors have been noticed close to the present lighthouse in inter tidal zone. Being in the high tidal range, the stone anchors that are lying in 5 to 10 m water depth during high tide get exposed during low tide. These stone anchors are found either partially buried or exposed on the gravel bed. The seabed at the finding spot of the anchor consisted of gravel and fine sand. The majority of the anchors are of Indo-Arabia type and one stone anchor falls in the category of composite type. The Indo-Arabia type anchors of typically made from a vertical stone block with often square section with two lower holes are rectangular/ square and an upper circular hole. Two anchors in the group of Indo-Arab type are having uniform vertical deep and wide groove on all the four faces of the anchor. The broken single composite anchor is made of a thin limestone block with two lower holes are square and two circular holes are placed randomly on upper side. The detail measurements and drawing could be completed just of 14 anchors due to tidal time and muddy seabed and hence rest anchors were only photographed. Many stone anchors are fragmented in nature. Majority of the anchors are parted with lower 2 holes and sometimes holes also broken which might have been broken during manufacturing stage. The raw material used for these anchors are hard basaltic, sedimentary and a few of conglomeratic material. A fragmentary anchor is the biggest anchor found from here. Only lower portion is surviving and is very similar to those reported from Mithi Virdi. There is a stone block without any holes noticed similar to the Indo-Arabia type anchor.