Lake Galena only has ~175 acres of 'sailable' water .... about 1/4" sq. mile.
Nockamixon has 1600 acres, mostly all 'sailable' .... about 2.5 sq. mile.
I live right next to Galena and keep a large sport boat at Nockamixon 15 minutes away, ... and a 'big' boat on the Northern Ches. I used to sail the Del. River but there are too damn few places to anchor and the currents can be tremendous, especially if there is heavy rain or flooding on the upper Delaware as has been the case for the past 6 weeks.