An Instructor and his student aboard a Robinson Helicopter experienced an encounter with Coast Guard Helicopter while departing TOA airspace. The reporter believes the Coast Guard aircraft failed to yield right of way.

Narrative

I was just coming out of the airport airspace and was attempting to cancel with the Tower on a southern shoreline transition. I couldn't reach the Tower to cancel (because of a mountain) when I saw a military helicopter 30-40 degrees to my left at approximately same altitude on a northern shoreline transition. I was looking at my location on the map and changing frequency to common when my student mentioned the helicopter was cutting in front of us. I took controls and based on the Class B to the surface on my right I climbed above the helicopter approximately 400 FT when he passed us. He then made a right turn and continued up the shoreline.I feel that adhering to the right of way rules could have made it a better transition. It's a very busy area when you are not used to it. I feel if the other helicopter would have gone to the right as described in the FAR it would have also been no problem. I am not sure what the military's requirements are so this is why I decided to climb and watch his actions since he wasn't doing what I am accustomed to.