Give him a chance
It took me about 1/3 of the first book, Master and Commander, to "learn" how to read his books. Like you, I started it and then stopped. I then went back and picked it up again and got to the point where I realized that I didn't need to know the name and location of every deck, sail, rigging, etc. on the ship. As you read, the story is more important then every minor detail. Also, the more you read, the more you will understand, but it will be enjoyable either way. I've read all 21 of his books and am on my second read through on them. A word of warning, they are very addicting!!!!