Tell her to man up and get a #1.
This is a simple thing. Does she, in other areas like excitement? If so lure her onto the boat with the promise of dinner or whatever. Talk to her about shoes..that can work.
Give her a job on the boat (like keeping fish off the tramp) in mid wind strengths and let the boat tip little more than it might and then tell her you could not have done without her. Tell her she has NEVER looked more beautiful.

Go to a sauna or somewhere special as a wind down and she will be hooked.

However if you think that what you really have here is a beach princess, (if she did not come with her own PDF or a photo of an outboard motor this could be an indicater) face up to it, buy a sandbag and put it on its own traveller.
The veiws expressed here do not neccesarliy represent those of bla bla bla.