If you share the information with Danvers you will help Bannon and he'll lower his prices. Visit Seagrave's quarters and if you're thorough, you will come across information that ties him to the slavers. Bannon will ask you to find evidence that would implicate Holmes in shady dealings. During your conversation with Bannon you'll find out that Seagrave Holmes is trying to take his place in the city hall. Similar to Megaton, the amount of caps given to him is equal to amount of karma points gained by performing this good deed. You can agree to contribute by giving him bottle caps (max 100 caps at a time). During your initial conversation with him you'll find out that he's running Saint Monica's church in Rivet City.
Father Clifford can be found in Rivet City - Bridge, Rivet City - Upper deck or Rivet City - Middle deck. If you're playing as a bad character you can share this knowledge with Sister. In exchange she'll inform about the Temple of the Union. You can give her 25 bottle caps, so that she can purchase a weapon to defend herself. Talk to Mei and listen to her story about the slavers. She can be found on the top deck of the ship or in Rivet City - Middle deck. The situation here is very similar to Megaton - you can him refined water and in 'exchange' you'll raise your karma. You should be able to encounter a beggar named Carlos near the bridge leading to Rivet City.
