Reasonable people thought that the ocean (without america, there would be no separate atlantic and pacific ocean) was considerably smaller than it really is, no

Reasonable people thought that the ocean (without america, there would be no separate atlantic and pacific ocean) was considerably smaller than it really is, not least due to the impossibility to reliably measure longitude, so they vastly overestimated the east-west extension of eurasia. Just look at the globes Behaim made in 1491-1493 (based on data by Pope Sixtus IV) which shows a really small ocean: http://en.wikipedia.org/wiki/Martin_Behaim#The_Erdapfel http://en.wikipedia.org/wiki/Martin_Behaim#The_Erdapfel According to the best contemporary data, the investment would have been highly speculative (as all voyages across the sea), but not insanely so.