How can i use my navy experience to qualify for hours worked on a ship for upgrading my master's cert?

You have to submit your papers for evaluation by the USCG. All the forms and instructions can be found at www.uscg.mil. Unless you have command experince, it's not likely they will allow you to take the master's exam right off the bat. You may have to first qualify for a deck officer's license, get some sea time on it and then upgrade.

Your DD 214 will provide all the evidence the CG needs. If you were a yeoman, gunner or mess cook it would be of no assistance. You would have to be deck department and get a testimonial for your immediate supervisor that navigation/handling fo the ship was part of your responsibility. In any case, unless the Navy was willing to put you in command of the ship you will have to work your way up through tonnage or rank. Good thought but a bit Naive.

I had to have a( transcript of sea service )from my navy records in the 80's

Just as merchant marine experience isn't any real help in the navy, navy experience isn't any real help in the merchant marines. Your sea time could allow you to skip the ordinary seaman job directly to AB, but that's probably as far as you'll get. Don't worry, a good AB job pays better than a navy officers job anyway.