Nesting Black Swan

Three weeks ago during our daily swim, Jen and I noticed a swan nesting in the reeds on the other side of the lagoon. We swam over to check it out but didn't want to get too close as she seemed rather concerned, so have been watching each day during our swim, from a distance.
Today Hanne and I went for a swim, (and what a stunning day it has been!) so decided to investigate again. She is still sitting on the eggs, got quite het up, and we couldn't see a thing. Decided to get the row boat out so that I could take the camera and get a photo and we actually were able to get in quite close. Strangely she seemed less agitated than when we were in the water. 
I wondered how long it takes to incubate the eggs as really thought that we would have the cygnets by now, but found the following online and obviously there is still plenty of time, we just need to be patient!

"After the nest has been built, which typically takes 2-3 weeks, the egg laying process begins with an egg being laid every 12-24 hours. Once all the eggs have been laid, which can take 2-3 weeks, they will all be incubated (ie sat on to start the growth process) at the same time with hatching usually 42 days (6 weeks) later."