I have always thought of "breaker" as waves that break. But Darwin evidently uses the word for rocks close to shore.
"The coast to the north of Punta Huantamó is exceedingly rugged and broken, and is fronted by many breakers, on which the sea is eternally roaring."

I seem to remember down on the Kent coast we used to refer to breakers as the man-made wooden structures stopping erosion of a beach...? ~ not entirely sure about that - meanwhile the obvious sound breaking on the beach of my mind is a poem you probably know...

http://eir.library.utoronto.ca/rpo/display/poem2115.html

edit: second thoughts, I think that was breakwaters, and breakers were indeed the waves that did... oh well, my memory also breaks down :)

Several beaches in NY have stone piers, sometimes called breakwaters, but my parents called them breakers,(there is an other term for them, and yes, they are used to catch sand, and to help keep a beach from washing away.)

breakers are also the kids/machines (old/new) that break the clumps of coal as it comes out of the mine..


Oh sure if the news is true,
a silk shirt is the first thing i'll buy,
The calico shirt i'll throw in in the dirt
If the breakers go back to full time
(a coal miners song)

Dear Mav: that poem I have always thought poignant.
I found another place where Darwin used "breakers" to mean the waves only. I have a lot more respect for him than I did before I read this.