When we think of big ships, we tend to think of tankers or aircraft carriers, but in medieval times, ocean-going vessels were much smaller.
The caravel, made famous by the Nina and Pinta, was common in the early fourteen hundreds and was somewhere between 50 and 70 feet (15 to 21 metres) in length. The Santa Maria, considered a carrack, was only a little longer, at approximately 77 feet (23.5 metres).
The Sao Gabriel, Vasco da Gama’s flagship during his first voyage, was a carrack with a length of roughly 88 feet (27 metres), only a little larger than Santa Maria.
On his third voyage, da Gama sailed in the Santa Catarina do Monte Sinai, a carrack of approximately 124 feet (38 metres).
To put all of this into perspective, the PT boats of World War II fame were 80 feet (24 metres) long, roughly the size of a carrack.