The Orca times listed above are my understanding as well. :)
I think Tracy Arm might be cancelled at last minute for a variety of situations - in particular, the ice conditions. Since there's a bunch of calving that takes place off the Sawyer Glaciers, depending on the conditions, it might not be safe for the catamaran to get close - therefore, the excursion gets cancelled. This is obviously out of the control of anybody - all we can do is roll with the punches if this happens.
Masaki
