A Charm Against Drowning

Out to the boom was easy enough, and over,
But there the treading water trod me down.
There, faithfully, I died for my instructor.

Your champion chums across the tideless bay
Half a cool mile - but, splashing awkward fins
Your drowning man is drowning all the way.

Land crawls ahead. You die a little, and lie -
Dead jaws gnashing the surf, English and mad -
...