between about 4 and 8 km per hour, for about 20 hours in a row , in the middle of a 50 hour swim? yep , thats pretty good. 

MarathonSwimming
between about 4 and 8 km per hour, for about 20 hours in a row , in the middle of a 50 hour swim? yep , thats pretty good. 

MarathonSwimming