According to the terms of the treaty what would happen if portuguese ships sailing on the spanish side of the boudary line discovered land and vice versa

According to the treaty, the Portuguese ships could not sail on the Spanish side or vice versa, but with the bulls, after Columbus's trip and his discoveries, they agreed to keep the lands discovered if they did not belong to the command of the other kings.

Explanation:

With the Alcacova treaty, the kings of Portugal and Spain divided the continent of navigation through a parallel line in the Canary Islands where the Spaniards could navigate and conquer the north in that line; Instead, Portugal sailed and conquered in the south of that line .

But everything changed when Columbus had to travel south and discovered new territory, which made them sign new agreements known as bulls where the Spaniards stayed with the places found while they were no longer under the command of the kings of Portugal.

Likewise, with the Treaty of Tordesillas, the territory discovered was divided again with an imaginary line in the Cape Verde Islands, where Portugal was the west of the lands, and Spain was the east of the discovered lands.

I hope this information can help you.