We have swimming raft where I work and they get stored for the winter in more protected waters. A few years ago a pair made a nest on one of the rafts. I had to convince the harbormaster and the local bird sanctuary to let me erect a pole and move the nest. It was a bit of a fight but they finally gave in. A buddy of mine had an old raft that was not usable any more so we made a pole on it and went out and moved the nest to the other raft. The osprey were pissed and kept diving on us but we pulled it off and they took to the new digs with no problem. We probably help them out really as the nest now had some support. The one they made was just sitting on the raft and it would have blown off at some point.