Draw the polygon until you reach the node limit, and then use "ADD" to create additional polygons for the same feature you are adding. You only do one set of information, but you can do numerous polygons this way. Ensure you have an overlap as others have mentioned, and it will look like a single lake/park etc. when you are done.
http://goo.gl/TfHeJ is a link to the User Guide article about adding multiple shapes to a large river. It's the same as for a lake.