A.S. GAUR, A. SUNDARESH
National Institute of Oceanography, Goa
Ancient Technology of Jetties and anchoring system along the Gujarat Coast, India
The port plays a dominant role in facilitating the sea trade and there were several ports all along the India coast since antiquity. The prerequisite of the selection of any port site include a sheltered place particularly protection from high wind and rough seas, sufficient water depth for sailing the vessel and a suitable anchoring point. The Indian coast, with a long history of the maritime activities, has been dotted with several ancient ports. The evidence for this exists in port-related structures on shore and in relics lying in the sea adjacent. Marine archaeological investigations during the last one and half decades have revealed the existence of jetties at Dwarka, Rupen Bundar, and Porbandar and of offshore anchoring points at Bet Dwarka, Miyani, Visawada and Somnath, Kodinar, Hathab and Ghogha on Gujarat coast. The preferred anchoring points fall in water depth of 5 to 7 m. The underwater observation revealed that seabed topography between Bet Dwarka on the extreme west and Somnath on the East is almost less variant particularly at Dwarka, Miyani, Visawada, Porbandar, Tukda and Somnath. The seabed topography is comprised of the rocky formations with numerous channels filled with fine sand. The stone anchors were trapped in these channels and between the rocks, which were suitable for holding big boats like Arab Dhows and Indian Vahan. The observation at Bet Dwarka and Porbandar revealed that boats of carrying more than 100 tons of cargo are anchored in a water depth of 4 to 5 m and some time they are resting on the sandy beaches during low tide.
This paper also discusses the effect of tide when using jetties and anchoring points along various parts of the west coast India. The archaeological evidences indicate that two gulfs of Gujarat coast (Gulf Kachchh and Gulf of Khambhat) witnessed the hectic maritime activities in the past. Both gulfs have very high tidal range and the Gulf of Khambhat has the second highest tidal range in the world (11 m). Ancient texts such as Vishnu Puran and Periplus of the Erythraean Sea vividly describe the tidal range and its uses for the navigation purposes. The discovery of the large number of stone anchors in inter tidal zone along the gulf region support the above references.