Ok, so now I'm cleaning coffee off of my monitor. Some may recall an incident I had two seasons ago. I had written a bit about it. The wording you posted is ironically close to what was on my insurance policy. Yep, you goota read that stuff CLOSE. Mine also had that limitation. The options on mine were:
A) maine to Virginia (Tidal Waters)
B) Maine, NH, MA, RI, CT, NY (Non-Tidal Waters)
The Non-Tidal Waters was not very clear (above is abbreviated). Both I and my ins. agent knew where I was boating. We both missed it. It was pointed out to me when the insurance company denied a claim. I'll dig around for that old thread. At the end of the day, no matter what, it's still the captains fault.
Nice catch. Call your agent and make sure she calls the underwriter for clarification on what you need to be properly covered. This is what I found to be the problem. Your agent can't possible know everything about ALL insurance policies and things insured. They have to know cars, trucks, planes, boats, motorcycles, construction equipment, personal lines, business lines, property insurance. They have to know the nuances of multiple insurance companies since an agent represents several. Insurance agents are extrememly knowledgable and can typically answer most questions. They can look up what they are unsure of. Most importantly they can call the underwriter at the insurance company for ultimate verification. A good agent will do so automatically. In this case, I'd point it out and ask the agent to verify what changes you need to make.
On a side note, expect your premium to go up a lot. I increased the insured value and tacked on replacement for itemized contents and my premium more than doubled.