i rather thought that poor frenssen was having a nervous breakdown, and pilgrim, bless him, was being a true friend by not abandoning him...
as fer der alte, when he does drop, he's initially lying on his side with his back to the camera. you can see some round holes in his sweater that weren't there before...
the expression in his eyes as he watches his boat go down just kills me. he's grieving for the "death" of his boat; the irony of it is evident, the men slaved to get that boat up, and now she's sunk at her moorings in her home port. he's making no effort to save himself, as if he knows he's done for, but he's still allowing himself to feel the emotions the situation evokes.