Where can I learn about the voice procedures, military jargons, submarine communications and politics involved in navy?
The best place I can suggest to turn to with this kind of open questions - on military and weapons - is 4chan/k/. It's an imageboard gathering fans of all things connected with weapons of all kinds, and military is a significant portion of their interests.
I'm not sure if they will know much detail about submarine communications and politics in the navy, but if anyone knows where to find that stuff, it will be them.
Be warned, 4chan is a specific subculture, many of its boards are NSFW and while /k/ isn't one of these, the contents of others sometimes spill over into SFW boards and you may encounter NSFW content before moderators catch it. Also, its specific culture is connected with particular jargon, ways of communication, and "traditions" - I suggest you spend some time "lurking" (just browsing the board and learning local customs) before you start asking your questions. The time spent will be useful - if your writing involves weapons, military, survival and such topics, you'll be returning to /k/ for advice.
I would advise you to get hold of a number of non-fiction naval books and start reading! Ideally look for biographic works, rather than factual books, as these will contain more insights into jargon, etc.
Do NOT use the internet as your primary source of information, as inaccuracies can slip into stuff like wikipedia and 4chan very easily.
If possible see if you can find a veteran's forum and ask questions there, from my experience ex-forces personnel are usually quite happy to answer questions.
There are several specific texts that could help you out. First is the 'Blue Jackets Manual'. This the text issued to Seamen during Basic, and covers pretty much everything you could ever want to know about functioning in the Navy (Think 'Boy Scout Handbook' for sailors). Secondly, there is a smaller text issued to officers called 'Reefpoints' that is issued to Midshipmen at the Naval Academy.
As for politics, I can't recommend 'The Caine Mutiny' highly enough (the book, not the movie). Speaking as a salvage ship veteran, that book could have been written by any of the junior officers onboard, despite being set in WWII.