Answer:
This would depend on the time of the year, and I have only done it with lots of stops so its hard to say, but I would say you could do it in about 10 weeks. The first part from Buenos Aires to Angra dos Reis, would take about 3 weeks, with stops in Punta del Este and Florianapolis. From then on it really depends on where you want to stop, you could go to Joao Pessoa and from there to Salvador in another 3 weeks, and count 10 days from there to Chaguaramas. Then it`s hard to estimate as you will be sailing along the cost of Venezuela and then the ABC before Panama. Call it another 3 weeks reallistically.