Plugin Recommendations?

I am trying to find a suitable membership plugin. Or that’s what I THINK I am looking for.

The idea is this: there’s a boat club. People can register to be members. Each member has one or more boats and they can register as many boats as they want under their own name.

After which, ideally, they would be able to enter races using a form and they would enter their boat by selecting one from a list of their boats.

I don’t care about boats specifically. What I need is basically a membership form where you can create many sub records.

Whether it’s boats and owners or school kids and families or houses and estate agents… it’s still the same concept as long as I can edit the fields.

Is there such a plugin anywhere or do I need to write my own?

Thanks for reading this far!