My experience with insurance companies is that they find loopholes in anything.
1: A friend had a neighbours tree fall through his house during a bad storm. Neither insurance covered it.
2: I had an office which I vacated and with the landlords permission left furniture and fittings in case the new tenant wanted to buy it from me. New tenant moved in when landlord was away, communications
got crossed and they destroyed, threw out and/or claimed all my stuff. No come back and insurance refused to pay. No break in. The new tenants had a right to be there and keys. Same goes for your house, and I presume boat. If anything is not locked and/or the theif did not break in then no insurance.
I reaslise both of these are dry land. But.........
Lucky you are ok and no one was hurt.
More examples: Flood damage in Qld?
I am sure we can think of heaps.
My favourite maritime insurance movie
is the Billy Connelly fim "Act of God" I think it was.