I had a horrendous time finding this, but I am a very persistent and determined person!
A walkthrough for this game can be found at the following link:
http://rayearlesgamehelp.info/Wfiles/Whale's_Voyage.html
I found a German version of this on
www.dlh.net, and no online translator could translate it properly, or completely, which made me more determined to find this one, which is the same walkthrough! It is on the page for solutions for Amiga games, but it should be compatible with the DOS version (I hope!)
I also found out from Mobygames that "Whale's Voyage" is the European name for this, the U.S. release of this game was called "Distant Frontiers" for some reason.