There is no guarantee that boats will be able to make it to the face of the glacier in Tracy Arm. The fjord is 22 miles long and twists and turns its way through a flooded Yosemite Valley. If the floating ice packs up due to wind and currents, you won't make it to the glacier itself. The comparison to Yosemite is not just hyperbole. The rock is similar, the waterfalls are frequent, even the carved domes are the same shape. If Tracy Arm were Yosemite, the Sawyer Glacier face would sit roughly at Happy Isles, and perhaps also just beyond Mirror Lake. To finish the comparison you have to mentally flood the Valley, sort of like Hetch Hetchy. As we got closer to the glacier the bergs crowded in, but always left us enough room to get through easily. We could just pick a path and go slowly.