...

Three days. It doesn’t seem possible that it’s only been three days since Mac died, the last of a crew of seven which once seemed so few; now an unbearable weight of responsibility, a psychic pain to accompany the physical pain in your belly which is killing you. The ice has built up overnight again, heavier this time, cancelling any hope you had that the weather might turn warmer. You try to muster some grim amusement at the knowledge that you, the captain that managed to get his crew lost and icebound aboard a rust bucket you knew to be unseaworthy, would be the one who would fade out last; alone, starving and freezing in a slowly constricting cell of ice on a point of the earth no man has any right to expect better from. No, you only find yourself thinking over and over, as if to transmit your thoughts across the mortal divide to the dead men bundled below deck, I'm sorry.
Not having the strength or will left to chip away pointlessly at the ice as you have been in an attempt to keep warm and sane, you go below deck to try sleeping again. You've been huddled under a pile of blankets for what could have been hours or minutes, you've lost the ability to tell; in your blank state you only slowly recognize the tapping sound you've been hearing this whole time is patterned.
It's Morse code. You're on your feet before the realization settles. Removing and turning over the drawers of the radio cabinet you find your code translation book. You can barely hold it open with stiff, frostbitten fingers as you decipher the message.
One word, repeated over and over, making no sense, damn it; it reads:

U-N-T-E-T-H-E-R-E-D