Good chemistry
Both Coop and Chuck Heston create sparks playing off each other in a subtle way;there is introspection here and intial distrust for the other as each one tries to get the upper hand(one wants to keep a secret while the other wishes for the salvage of a ship for monetary gain)-and yet,before its all over,there is quiet dignity and respect for the one and the other: mutual admiration.
Indeed this is an overlooked and under-rated sea faring Tale.
-mby