CALL THE USCG. I don't know if they are or are not prohibited from responding, but generally they will find a way to respond IF they have any available resources, AND by doing so they can save lives or property--which would include preventing the oil spill and submerged wreck that this situation could easily cause.
If you couch it in those terms--preventing an imminent disaster with immediate threat to an environmental incident--they may be able to tow away both vessels, or at least add anchors to them.
For an overworked, underpaid, harried organization with too few resources, they still manage to go out of their way to outperform the "requirements".
Call 'em. Pitch it to them as preventing etc. as above. If that doesn't work, use the stick: Start down your list again, and at each agency, tell the person on the phone "OK, now what is your name and position please? I'm documenting these calls so we have a record of exactly who is responsible for the damages that are about to happen." If necessary, call the local waterside businesses or civic associations, local ward or other lowest-level political rep, mayor's office, etc. And again remind them--this is like a house on fire, if everyone ignores it, it could spread and there could be more losses and damage to the community (the waterfront).
(I'm hoping the one first call to the USCG does it.)