If I and the majority of others understood the situation correctly it was all down to money (Discovery was not full so had fewer passengers to cover the costs) although none of the staff up to and including the Captain would confirm that! All we were told is that it is all down to the Canal authorities which ship they let through and when and we have that in writing from the MD of Discovery in the US. He must think we are all idiots to believe that load of tosh. We sat at anchor off Fuerte Amador all day waiting to go through but the Captain had already been told of a scheduled transit starting at 4.00pm which was delayed till about 5.30. Whilst we were waiting Volendam came out heading into the Pacific at about 3.00pm so had managed a daylight transit as every other cruise ship I have heard of does.Discovery knew well in advance of the schedule change but chose not to tell the passengers so the scuttlebut really got going on the subject.I confronted the Shore Excursion Manager amongst others with the simple question "are we transitting at night?" She should try going into politics to judge by her evasive answers but would probably be no good at that either! She finally admitted that the rumours were true and night it would be; for those interested I can tell you that you don't see a lot and there were very few ships going through. We finally left the Gatun locks at 1.00 am
My reason for mentioning it is that if you want to guarantee seeing the Canal in daylight choose another ship.