Ocean flying has very specific deviation rules. Anything more than 10 miles left or right of track requires ATC coordination. As always, the trick is to put in your deviation request well in advance, as it sometimes takes ATC quite a while to get back to you. Absent that, you can change your altitude +/- 300 ft (depending if you are eastbound or westbound) and deviate as required, while broadcasting your intentions on 121.5 or 123.45 and illuminating all exterior lights.