The following are the meanings listed in the dictionary against the phrase ‘take on’. In which meaning is it used in the third paragraph of the account:
take on sth: to begin to have a particular quality or appearance ; to assume sth
take sb on: to employ sb ; to engage sb
to accept sb as one’s opponent in a game, contest or conflict
take sb / sth on: to decide to do sth ; to allow sth/sb to enter e.g. a bus, plane or ship ; to take sth/sb on board
In the third paragraph of the account the word ‘take sb on’ means to employ some body.
For example:
‘We took on two crewmen—American Larry Vigil and Swiss Herb Seigler—to help us tackle one of the world’s roughest seas..........’