In Salvador you can stay in the marina "Centro Náutico da
Bahia," which is in a very good location, just below the Lacerdo elevator and near the municipal market. It's inexpensive and has easy access to the sights in Salvador.
Socicam - Terminal Tur?stico N?utico da Bahia (TTNB)
After visiting the city, most people go to the island of Itaparica, where you can
anchor near the town (water, groceries etc.). Then there is the rest of the
Bahia de Todos os Santos to explore.
Are your friends going north or south after Salvador?