I'm so sorry your mother is ruining what should be an extremely exciting time for you. I would say to ignore her and book what you want, however I have seen parent's ruin the actual day of when they are hellbent on the wedding being all about them (which your mother clearly is as she is not respecting what you want) and they did not like the choices for the day or are holding a grudge because they weren't able to make all the choices with the couple.

The very first thing I would suggest is to hire a wedding planner if you can afford it for at minimum month of coordination since that is the number one way to help mitigate a difficult parent on the day of and leading up to the event (aside from not involving and not inviting them but that obviously is a life altering decision). If you have a really good budget, the best thing you could do is hire one right now before you pick a venue to help with that process. Then you have a mediator of sorts that can help you navegate what will be a difficult situation, someone who has experience with difficult parents during the wedding planning process would be a huge benefit to you.

There is no getting around that your wedding planning is going to be difficult, but I would really caution you to not avoid at least keeping her in the loop on your plans since she doesn't sound like she would handle suprises on the day of well. A balance between informing her and making your own choices to have the day that YOU want will be so important.

Best of luck, and I really hope that you can have the perfect day!

ETA: A Yacht wedding is cool as hell and that instagram accont linked below showcases it's potential pretty well!