That actually sounds much better than the usual "puzzle-style" interview questions I hear. I'd personally begin by asking for high-level details. What applications do you have in mind? Alternatively, are you looking for a specific sort of boat? Without knowing the first thing about boats, there are obvious orders-of-magnitude design, process, and resource differences between building a kayak, say, and an oil tanker. Note here that I'd be careful to avoid detailed design or requirement questions: by my own admission, I don't know how to build boats, so the resulting "requirements discussion" would almost surely be "bike-shedding."
Next, given that there's (presumably) a well-established industry selling ____ boats, why are we assuming at the outset that we should build rather than buy? Suppose the answer is "we're not an end-user, our business plan involves breaking into boat manufacturing."
Fair enough. Then doing profitability requires both building and selling boats in a market with established players, and, by our (my) own admission, we (I) don't yet know how to build a boat, let alone do so well enough to make a manufacturable and marketable product (not to mention the highly nontrivial matters of actual marketing and manufacturing "at scale"). So unless we already have a crack boat-design team at our disposal (in which case, why are you asking me?) it might bewiser, at least for a few years, to get our feet wet by OEMing third-party boats, building something related but less ambitious like "boat accessories", etc., before committing to full-on "boat-building."
And so on. Presumably this is the sort of discussion they want to hear?