Here is an article I wrote listing the graduate and double bachelors programs that are offered by the 7 maritime academies.
In your case, you have proven that you can compete at the collegiate level. If you don’t have a burdensome amount of debt I recommend you pursue the masters or even a double bachelors.
The study habits you have built over your first degree will give you an edge over 18 year olds fresh out of high school.
In addition to having an edge over other freshmen, professional administrators file your documents for you. They will ensure that all your paperwork is in order which saves you time and the cost of having to consult a licensing professional when it’s time to upgrade.
In addition, the 3 year masters is faster than hawsepiping. 1080 sea days are needed to take the 3rd mate classes and exam at nautical training schools such as PMI. The fastest you could possibly accomplish the sea time requirement would be in 2 years sailing non-stop on a vessel granting 1 1/2 days of sea time for every calendar day. A more reasonable time frame would be 4 1/2-6 years allowing you to take time off every year. After getting the seatime you would have to spend weeks in classes in order for you to be certified to test for your license.
The only viable circumstance I would recommended hawespiping would depend on your current financial situation. A master’s degree will likely incur costs between $90,000-$120,000. Your post-baccalaureate loans are likely to be interest bearing.
If you already have interest bearing debt, that debt will grow while you are in college. You could very well have a 3rd mates license and 6 figures of debt at the age of 30.
This could mean that you could be spending $3500-6000 a year paying back the interest alone. Assuming you netted $50,000 after taxes, you would be spending over 10% of your take home pay on your loans. These loans may take decades to pay off at that rate. At 30, you may want to buy a house. This will be much harder with such a high pile of debt hurting your credit score.
In summary, post baccalaureate canidates can get their license fastest through a 3 years master’s or double bachelors degree program. However, you should consult a financial advisor on your financial health and determine wether or not graduate education is a sound investment.