Ultimate Survival Alaska - Season 1 - Eps 4: Sink or Swim
The eight explorers are on the fourth leg of their expedition and are struggling to stay afloat on the Talachulitna River. With currents rushing at dangerous speeds, it's no easy feat to navigate the frigid waters. Expert climber Willi Prittie teams up with Iditarod champion Dallas Seavey and his brother Tyrell to find a much-needed food source. Meanwhile, mountain man Marty Raney and his son Matt enter the river further downstream hoping to minimize their time on the water.
About Ultimate Survival Alaska

Title: Ultimate Survival Alaska
First Air Date: 2013-05-12
Last Air Date: 2015-03-22
Status: Returning Series
Rating: 8.2/10 (from 4 votes)
Language: EN
Seasons: 4
Total Episodes: 38
Network: National Geographic
Genres: Reality, Documentary
Production Companies: Brian Catalina Entertainment
Synopsis
They are some of the toughest, most extreme survivalists from across the nation. In the second season of Ultimate Survival Alaska, four teams - woodsmen, mountaineers, military veterans, and endurance athletes go head-to-head in an epic arctic competition that only National Geographic could inspire.