A small digression before we meet Henry the Navigator who will do much to push Europeans into the deeper oceans… any discovery of Terra Australis is also linked to the evolution of shipbuilding technology… and around the 13th & 14th century things were changing…

In the northern waters of Europe ships known as cogs evolved (from the Celtic flat bottomed boat). The Cog was a perfect load carrier, square rigged, carrying up to around 140 tonnes of cargo. By the 13th century, with the growth in in the scope of European trade, the Cog appeared in Mediterranean waters. However, with only a single mast its handling left something to be desired and was largely relegated as a cargo carrying work-horse.
However, the Cog influenced the development of the Carrack which adopted the rudder of the Cog and added a lateen rig to the mizzenmast.
Carracks became the first true ocean going vessel, with the stability and size to withstand the rigors of the deeper ocean. Carracks that were used by the Portuguese as they first ventured from their shores along the West African coast in the Atlantic.
These Caravels started out quite small at 50 tonnes, but grew larger and, in the 14th century, adopted similar rigging of the Carrack (a foresail, square mainsail and lateen mizzen).
The main reasons it was also chosen by the Portuguese for exploration were its speed, ability to sail windward and its maneuverability. Indeed, it was in Carracks and Caravels that Columbus set out in for America in 1492.
And so, under the sponsorship of Henry the Navigator, Portugal now had the technology to venture past the north coast of Africa towards the far ends of the earth…and a continent unknown…