Your question needs to be referred to an insurance agent, and I'll be glad to do that, but first do you currently have Homeowner's Insurance? Secondly are you referring to the town of Ocean Isle or to the town of Oak Island, and do you know what flood zone the house is in?
If you currently have Homeowner's Insurance then your most accurate answer is going to come from your agent. I highly recommend you pick up the phone and give them a call. Or you can call any of the larger companies, Nationwide, State Farm, Farm Bureau, AAA just to name a few. There's also a number of independent agents that could easily give you a quote.
Sorry we can't assist you with a concise answer, but a Realtor's area of expertise is real property not insurance.