Answer:
"Narrow clip" means a close call. "Broken sea" is referring to the waves on the ocean.
Explanation:
"Narrow clip" most likely means a close call, or a dangerous situation that he only just made it out of. He appears to repeat the phrase over and over again almost in astonishment, and it seems like that is what this refers to.
"Broken sea" is probably referring to the waves on the ocean. Water is often thought of as still, so with waves, it will probably look almost broken.