I'm in the CG. I do boardings, but not the type you're probably interested in. I'm an MST (Marine Science Technician, or Master of Sexual Techniques, whatever) and I do boardings of foreign freight vessels to ensure compliance with international shipping regulations. If you want to do law enforcement stuff, you'd be better off going BM or MK. If you go GM, you might end up being in charge of keeping track of sidearms at an air station, and won't get to do much boarding.
As a BM, you'll drive boats. Most likely 41' Utility boats, 44' and 47' Motor Life Boats. If you want to be a Boarding Officer, there's a school you go to where they train you how to do that. As an MK, you'll learn to be a mechanic and work on engines. Both ratings are very labor-intensive, and BMs and MKs are a dime a dozen (they're some of the most popular ratings). The upside to this is that there are LOTS of jobs available all over the country. The downside is, re-enlistment bonuses aren't very good and you're competing with a lot of guys when it comes to promotion time.
I suggest A) talking to a recruiter, or B) talking to Boarding Officers and boat crewmembers who are in the area you are interested in. The actual guys in the field are gonna be a much better source of info for you than the recruiter (I've learned this from listening to everybody bitch about how their recruiter wasn't completely honest with them).
Whatever you choose, good luck!
[i]Semper Paratus[/i]
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