While I'm not a gunboat player I did draw Russia in a recent gunboat.
I kinda got lucky on number of levels with this one.
gameID=52579Germany opened to Holland (England bounced Den), and Austria opened all out south.
Which left me only with England who had opened against me and Turkey who had opened against me to worry about.
First year was a pretty standard Russian opening. Except to show that I supported Austria I offered support to gal.
The next three turns are about getting your enemies off your back.
In this case I gave up Rum, and did my best to hold off England in the north.
Now really this strategy could work with most situations. Your prime goals should be to ensure either E/G knows they have your support against the other, and A/T knows they have support against the other.
Should that fail, try and make one power a threat to the other. By giving the power a center they normally wouldn't get near a center of the other power you want them to fight.