This was indeed a very unique film. It was an unusual way of telling a story - but it was a way that actually worked. I am surprised that very few other British films have not been made in the same way.
The film was unusual, inasmuch, as none of the actors actually spoke. The dialogue was put over purely by narration.
This type of film would have been easier to sell to a country where English is not the first, nor accepted language - dubbed dialogue can sometimes be a bit irritating and subtitles tend to distract the cinema audience from what is actually happening on the screen.
However, I think the ending may have been sadly misunderstood, especially by younger audiences, but there was probably a moral or a message in there somewhere, but I do not know where. Perhaps the film makers were trying to say: "The sea gives, and the sea takes away - without any thought for the innocent".
My own thoughts would be that you should never underestimate the power of natural adversity, whether it be weak or strong; and, as well as good training, experience is sometimes the most influential teacher.
Learning the hard way only benefits those who sadly and helplessly look on.
The sea cannot be tamed, trained, nor subdued - it should always be respected.