deltabighat,
We left from Alameda at about 9:30 in the morning to be in San Pablo Bay close to high tide so the water depth was never less than 15 feet even at the entrance of the Petaluma River. From the “Brothers”, with a course of 345 degrees, it was easy to pick up the well marked channel. Although, at high tide you could possibly use more space depending on your draft, we did not want to take any chances and we stayed in the channel watching carefully our depth finder.