Only another four miles today but not the easiest,first we found the tide to be stronger than expected. Then the big road bridge that should have opened regularly didn't so we had to wait around for 2 hours, there was nowhere to tie up so we went back about a mile and found a large steel post to tie too. We then had to wait another hour to get into the very small marina. The reason for staying at this marina was so we could visit the world famous windmills of kinderdijk, which are 2 miles away by bike. They are in fantastic condition having been there since 1738. They have been restored many times and have steel arms, but still looked great. After we got back to the boat we were sat enjoying the evening sun when two big burly police men marched purposely down the jetty to us. They were a unit of the immigration and customs special force. They asked us a lot of questions, wanted to see all our papers and the ships papers, they then photographed the boat and the documents. Then they phoned there boss and asked a few more questions. They then thanked us and left seemingly happy. No sooner had they gone, then the harbour master turned up to see if everything was ok. They had told him we were registered as a fishing boat. We caused quite a commotion in the marina as they had never been visited by this unit before. The reason that we were mistaken for a fishing boat is that when our new instruments were fitted, the engineer must have set it as a fishing boat instead of a sailing boat. We now have to find out how to change it before we enter another country or risk another visit.