Jim and Huck find themselves stranded on a derelict steamboat that they were hoping to rummage after their raft breaks loose and drifts away during the storm. Unfortunately, the steamboat isn't abandoned; two thieves are about to turn murderers by killing the third member of their party, all of whom had the same idea of rummaging. Twain starts chapter 13 with Huck saying "it warn't no time to sentimentering," and in searching for the thieves' skiff so they could make their own departure from the wreck,
"We went a-quaking and shaking down the stabbord side, and slow work it was, too - it seemed a week before we got to the stern"
Twain's use of hyperbole here suggests the seriousness of the situation Jim and Huck find themselves -- if they don't successfully depart from the wreck, they too may be killed by the thieves if they are discovered, or they may be drowned anyway as the storm breaks apart the wreck.