Hi,
I have anchored there but never spent the night. I don't think it
would be a problem though. There is a pretty strong tide current going
in and out of the delta under the San Rafael / Richmond bridge and
that will probably cause you to turn around with the tides.
I would recommend staying at the mooring at Ayala Cove on Angel Island
instead though. They charge $5.00 / per night but it's well protected
and you can go ashore to the bathrooms and even take the ferry to
Tiburon and San Francisco.
Jeannette Bristol 32, San Francisco
http://www.eblw.com/contepartiro/contepartiro.html