Boats trips around Porto Alegre

There are boats that do trips around these islands. I know only of 'Cisne Branco' which sets off from Cais do Porto and which does some sailings on Sundays. For a one-hour trip you have to pay 5$. And there is another boat, Noiva do Cai, which does cheaper trips, for oly 3.5$. You can take it from Usina do Gasometro.