Best way to lose 40 pounds in 3 months?

Hello, im getting ready to join the Navy and i currently weigh 231 pounds and im 5’11. Thats a problem. Iv set my goal pretty high just so i can try harder and hopefully lose more than i think that i can. Problem is, is that i dont know how to go about losing that much weight. I would like to lose the whole forty pounds. If anyone can give me a link to a great or better yet awsome excersise routine that can help me to obtain my goal i would be forever greatful.

P.S. I dont have access to a pool.