You mention you will be on VG and going to Anegada ( assuming by ferry from Spanishtown ) There are a few ferries that do this route. The smaller one is rougher. Yes the wave motion if it is a choppy day may be an issue.

Like others have said sit and look forward, no phone, lots of water, eat light , avoid heavy alcohol day before etc.

Bonine works very well for me if needed. I rarely get sea sick but have gotten queasy on a few occasions.

Assuming you are renting from Elaine at Leverick to do the island hopping. She won’t go in unsafe seas but it may get choppy depending on weather. Same advice applies . Bonine is a 24 hr thing so first thing in the morning on “ boat days”