Dhow (Arabic داو dāw) is the generic name of a number of traditional sailing vessels with one or more masts with lateen sails used in the Red Sea and Indian Ocean region. Historians are divided as to whether the dhow was invented by Arabs.[1][2] Typically sporting long thin hulls, dhows are trading vessels primarily used to carry heavy items, like fruit, fresh water or merchandise, along the coasts of the Arabian Peninsula, Pakistan, India, Bangladesh and East Africa. Larger dhows have crews of approximately thirty, smaller ones typically around twelve.The exact origins of the dhow are lost to history. Most scholars believe that it originated in China from 600 B.C. to 600 A.D. Some scholars claim that the sambuk, a type of dhow, may be derived from the Portuguese caravel.[3]
Traditionally Yemeni Hadhrami people, as well as Omanis, came to Beypore, Kerala, India along the centuries in order to build dhows. The reasons were the availability of good timber in the forests of Kerala, the availability of good coir rope and also the presence of skilled carpenters specialized in ship building. Formerly the sheathing planks of a dhow’s hull were held together by coconut rope instead of nails. Beypore dhows are known as ‘Uru’ in Malayalam, the local language of Kerala. Settlers from Yemen, later known as ‘Baramis’, are still active in the uru business in Kerala.[4]
Captain Alan Villiers (1903–1982) documented the days of sailing trade in the Indian Ocean by sailing on dhows between 1938 and 1939 taking numerous photographs and publishing books on the subject of dhow navigation.[5][6]
Even to the present day, dhows make commercial journeys between the Persian Gulf and East Africa using sails as their only means of propulsion. Their cargo is mostly dates and fish to East Africa and mangrove timber to the lands in the Persian Gulf. They often sail south with the monsoon in winter or early spring, and back again to Arabia in late spring or early summer.[citation needed]

For celestial navigation dhow sailors have traditionally used the kamal, an observation device that determines latitude by finding the angle of the Pole Star above the horizon( wikipedia)