Glossary help on 'Life on the Mississippi'

[lost galaxy]

Dear friends,

I'm translating this book into Vietnamese and stuck at chapter 7.

Although I've got all the nautical dictionaries I still can't make out what's meant, for example by

'It was in the night, there, and I ran it the way one of the boys
on the "Diana" told me; started out about fifty yards above
the wood pile on the false point, and held on the cabin
under Plum Point till I raised the reef--quarter less twain--
then straightened up for the middle bar till I got well abreast
the old one-limbed cotton-wood in the bend, then got my stern
on the cotton-wood and head on the low place above the point,
and came through a-booming--nine and a half.'

I once came across a lesson plan which was really helpful but it only dealt with one chapter. So any help as to where to find all the glossary guide for this book would be more than appreciated.

Thanks.