What if the Danes Were Trying to Make Landfall?

So what if the Danes weren't truly trying to make landfall? What if they were using their knowledge of the English military structure to absolutely demolish the English naval capacity. By striking so many harbors on the way to Northumbria, William would find it very difficult to quickly relocate large numbers of troops north. It might also explain why we don't have any records of William using sea power in response to the Danish threat. He and his bros were out there just hoofing it, and this could explain why.