The Arab efforts in the development of marine science and its impact on the maritime influence in the economic development and the spread of Islam and Islamic civilization in China and East Africa since the advent of Islam to the Portuguese occupation 913 AH / 1507 AD
Arab ships did not sail between Socotra Island and the Somali coast because the strong wind severely blew it ا was stronger from large flood waves ـ Zhonـ ـthese waves were entering from a strait between Socotra island and the head of gardfree ـthe whirlwinds headـ Arab Ships were forced to sail to Aden as that they sailed back to Muscat again and let the Socotra island on ships right even if they exceeded the great waves area they turned around Socotra Island then they sailed to Somali coast , they were not able to pass these seas with risk but renowned Omani sailors ـ Arab Azd ـ dared to fight these dangerous seas In order to get the goods, all Chinese were already desired in, reaping huge profits.
They brought from Yemen leather, because Yemen had huge animal wealth and tanning seeds which helped revival of leathery industry though Egypt preceded Yemen in tanning industry, which Egypt knew since Middle Egyptian dynasties age (2140 – 1785 BC) as we saw evidence of superiority of ancient Egyptians in the tanning at Beni Hassan tombs, ancient Egyptians engraved tanning pictures on the walls and Yemen likely took the tanning industry from Egypt in modern Egyptian dynasties age (1580 – 1084 BC), ancient Egyptians used acacia and safflower seeds in the tanning ,the Arabs have established settlements along the coastline from Mokadiso to Sufala and neighboring islands for trading,* the ships carried the goods from Muscat in order to sail from the head of skull ـ Ras Elgumguma- sailing in Dllaroy Sea ـArab sea ـ to reach to port of Dayble to carry the goods which the convoys had crried to this port then they sailed to Mansoura, capital of Sind, to sail south to Herkend Seaـ strait between west Indian coast and Maldive Islands ـ , AlFal andـ Allakadif Islands – Zibat Elmahl – which bordered that sea west these islands had great deal of amber, Arab traders replace the silk and cotton cloth with amber. .
while they were sailing in the Bay of Bengal -Shalahet Sea – where there were Linjebalos and Nekobar islands they replaced amber and Cocoa –nut with iron and clothes crossing Malacca Strait to South China sea to arrive to Hai – Nan ـ Taiwan nowـ and Arrameni Islands in Tin – king Bay finally they arrived to Canton – Khan- Fu – and landed Shang -hai-which was called now Yang- chou – to carry types of the goods as Sticks of incense, Musk ,Sable Pottery, camphor and Alkmkha – type of silk ـ from China they sometimes sailed to Yellow Sea to arrive Korea – Silla – in Chile Bay the Chinese ships arrived Seraph -on the eastern coast of Arab gulf to carry the goods ,which were carried from Basra and Oman to Seraph, the Chinese ships did not exceed Seraph because of the large waves in Arab gulf and the little water in some paces because the Chinese ships had a great load and they could not descend farther from Muscat port ,Whose eyes are open to the wide world, to take their need of fresh water from wells , there was place called the role role -Dour Dourـ Strait between two mountains – light boats followed only, Omani Arabs – Azd – made these boats to be suitable for this sea, we have to know the reason why the Chinese ships did not sail in Aden Gulf -Berbera Sea – the great waves forced Chinese ships to not keep at a large distance from Siraph because there were many whirlpools and the difficult windings, the most difficult pace was between janaba and Basra .it was fearful and excited, all ships were exposed to sink the sailors were afraid for the big Chinese ships, because load of a ship was from 50 to 60 tons.