Dhow Navigator
Sail from Julfar, near today's Ras Al Khaimah, with no GPS and no clock good enough to tell your longitude. You have al-Jady, the Pole Star, and a kamal: a small board on a knotted string that measures how high the star stands. Could you reach India the way Ibn Majid's navigators did?
How a kamal finds your latitude
The Pole Star sits almost exactly above the North Pole, so it barely moves through the night. How high it stands depends only on how far north you are.
At the North Pole the star is straight overhead (90°). At the equator it sits on the horizon (0°). In Ras Al Khaimah, at about 26°N, it stands about 26° up.
Arab navigators measured star heights in isba‘, a finger's width. One isba‘ is a little over 1.5°. Knots on the kamal's string were tied for the ports a pilot knew.
Sail north or south until the kamal reads your port's number, then turn and sail east or west along that line until land appears. That avoids the hardest question: how far east you are.
Longitude needs an exact clock that keeps time at sea, and those only arrived in the 1700s. Before that, pilots estimated it from speed, course and time, and the error grew every day. You saw that gap on your chart.
Ahmad ibn Majid of Julfar
Born around 1432 in Julfar, the old port near today's Ras Al Khaimah, into a family of sea pilots. His father was a well-known navigator too.
Around 1490 he wrote Kitab al-Fawa'id, a guide to the principles of navigation: stars, routes, coasts and the seasons for sailing across the Indian Ocean.
Julfar sat on the trade routes between East and West. A Portuguese traveller in the early 1500s described its pearl fisheries and merchants carrying its pearls on to India and beyond.
The monsoon decided the calendar. At the height of the southwest monsoon, roughly June to September, the west coast of India was almost impossible to approach and most harbours closed. From Oman to India, ships could sail in most months except about May to July.
Times varied with wind and route. The traveller Ibn Battuta wrote that his voyage from Calicut in India to Dhofar in Oman took about a month.
"Ibn Majid guided Vasco da Gama's ships to India in 1498."
This is very unlikely. The pilot who took the Portuguese from Malindi to Calicut appears to have been from Gujarat in India, and Ibn Majid would have been in his sixties. Sheikh Dr Sultan bin Muhammad Al Qasimi, Ruler of Sharjah, published a study rejecting the claim.
Sources: Paul Lunde, "The Navigator: Ahmad Ibn Majid", AramcoWorld (July/August 2005); G. R. Tibbetts, Arab Navigation in the Indian Ocean before the Coming of the Portuguese (Royal Asiatic Society, 1971); Philippe Beaujard, The Worlds of the Indian Ocean (Cambridge University Press, 2019), introduction on Indian Ocean navigation and monsoon seasons; The National (UAE) on Julfar's archaeology and Ibn Majid's birthplace; Gulf News on Sheikh Dr Sultan Al Qasimi's study of the Vasco da Gama claim; Duarte Barbosa's account of Julfar (early 16th century). The isba‘ as about 1°36' follows standard histories of the kamal. The game is simplified: coastlines are rough, the sea current is invented for each voyage, and the Pole Star is placed exactly at the pole. In Ibn Majid's day it sat a few degrees away and pilots corrected for that.