premise: young gentlemen wearing green shorts is walking towards the ocean with his surfboard. hypothesis: A man is walking outside with his surfboard.
entailment: A gentleman is a kind of man.  Oceans are typically only found outside, walking "towards" something implies that the walker is already in the general vicinity of the something (as opposed to walking "to" something, which only requires that the something be the walker's ultimate destination), and most buildings are not right next to the ocean; thus, if the man is close enough to the ocean to be described as walking "towards" the ocean, he is most likely outside.