What's the Name of That Book??? discussion

Looking for a book I read around 2011 or 2012, possibly earlier but only by a year or two
I dont remember much about it, other then that it was about pirates (I was going through a faze) and leviathans.
I unfortunatly don't remember much at all about the plot or characters, other then these pirates had to go through the waters where the leviathans where to get to something on the other side, and they used the skin of one to disguise the ship, rolling it down the sides of the hull.
There was a part in the book where it was from one of the leviathan's point of view, and it called the ship 'Deep fin'. I think it may have followed the ship away from the leviathan's area and maybe saved them later on?
I read it in school, so it wouldn't have been rated for anyone over young adult. The book itself seemed pretty new, wasn't terribly worn out, though I don't remember the cover or the Author but I think it may have been written by a man (Don't hold me to that though)
Read it in Australia, printed in English
I'm sorry, this is all I really remember about the book, but I remember it every now and again and I'd really love to read it again!

Could you clarify what you mean by "read it in school?" Was it an assigned read or was it something you got from the school library?

No response, moving to Abandoned folder.

Taylah (OP) was last active on the site in May 2021.