Out of curiosity, what is your birds name? Its just the last time your bird escaped it was called Poncho and you referred to it as a he, and now you refer to the grey as Bappy and female. Have you changed the name and sex of your bird, or did "Poncho" escape again?
With all due respect, and I sincerely do not mean this as an attack, personal or otherwise, but I do find your logic regarding Bappy flawed.
If you leave your bird free flighted in order to ensure she can fly back to you should she escape, she may well get tired, try to land on the ocean, get wet, be unable to fly and drown.
If you give your bird a severe wing clipping, and she gets spooked, flaps a little and manages to make it over the side of the boat, she will also drown.
Since you seem to be unclear as to which you are doing, perhaps you should also consider the third option of harnessing your bird when outdoors, as to the best of my knowledge there is no dangers associated with a harness.