I'm trying to catch enough info to find out the name of the company. If I do, I'll send them off an email. So far I have heard reference to a boat (tug?) called the Sara Lee (unknown spelling). Based on the strengh of the transmissions I think they are working out of the Port of Stockton and I did hear a reference to Three Mile Slough not being open. Sounds like they are moving barges around nightly on overnight trips, perhaps out towards Suisun Bay, but there are still a lot of unknowns. So, I think the quickest way to stop this is to find out who the operator is and send them a friendly email about the use of 61A. Here is one possibility: Tugboat and Barging Services | San Francisco Bay | Delta | Lind Marine