the metrô station estação carioca is about a 10 minute-walk away from praça xv. on this link by grupo ccr it is possible to check the schedule of boats going to praia de charitas by clicking on linhas, horários e tarifas on the top of the page. to check the return schedule, click on 'charitas' on the map, and select 'rio de janeiro' in the submenu. the fares are also listed.
