the company that operates quite a few of them is Tidewater. I have a friend who did a stint with them as an AB and said it was awful. Im sure there are a few other companies that also run supply boats out there. Good luck
Gulf offshore logistics runs out of Hueneme along with the tidewater boats. SoCal ship services runs workboats and crewboats out of long beach an Hueneme. Then there are some companies that have lightering contracts using supply boats out of long beach. I believe it's gulf mark and skaugen petro trans.
Tidewater has 2 OSVs out there and Gulf logistics has the 1 OSV. As far as I know So Cal Ship services only has a couple of older crew boats working out there also.
I can't speak for Gulf logistics or So Cal Ship services but I can speak for the TDW job. It's one of the better OSV jobs I've had for sure! If you live in the area and the boat is in port you can go home for a few hours. You can even run ashore and grab a good meal and a movie if you wanted. None of the other OSV companies I've worked for would allow that. The pay kind of sucks I've been told. 200-240 a day for AB and QMED 350-450 for captain and CE.
I have not worked out there for the past 4 years so it might has changed but I don't think it has based on what friends have told me.