As a former crew member of the CGC Campbell (WMEC-909) 2000-2002. First let me say congratulations to your friend on graduating the academy and assignment to Campbell. Sinbad lives!
As a junior deck officer there will be a strong likelihood that your friend will be encouraged to become a qualified boarding officer and member of a boarding team. To that end any knife you give will see hard use and be exposed to the harsh saltwater environment of the Caribbean. Also, it is very likely that as a junior officer he will either be the new Weapons or Navigation officer. Its a position often given to the newest officer who comes aboard, and in that capacity a knife would also come in handy.
Let me suggest you give your friend two knives. First a mid-tech or custom as you have suggested, engraved with his name and perhaps graduation date as a fine gift for graduating the academy and also a "Working" knife more suited for life onboard. Even if he is not doing boarding's right away a knife in your pocket onboard ship is always useful and will see immediate use. This is true for all crew members.
I would personally suggest a Benchmade Black Class, like a Contegeo, Rift or even Adamas. Or a Spyderco Manix 2 XL, Military, or Para Military. These knives will serve him very well and if lost or destroyed are more easily replaceable. During various operations any knife he has will be used and the likely evolutions he will see immediately will be Law Enforcement Boarding's, Alien Migration & Drug interdiction. Search and Rescue, and hours of flight and small boat operations.
Just tell your friend that once on patrol to keep his blade lightly oiled and clean from salt spray. The Southern patrols are brutal on knives. Tell him to go see the Gunner's Mates and they will take care of him as far as oiling up and cleaning his knife. He might be their new weapons Officer anyway.
Whatever you decide I'm sure he will be more than thankful, I just know the realities of life onboard ship and I can tell you right now that unless he keeps it in his stateroom and never carries it, any knife he carries will see use and you don't want it to be an expensive high end blade or custom.
I went threw a lot of knives doing boarding's so I can say if he does take it with him it can get damaged or lost over the side. It happens, especially when you are climbing the side of ships or boarding them. Not saying not to take a good quality knife. Just I wouldn't take a special or valuable gift with me while doing it.
As far as regulations, unless there has been some changes, I don't recall any restrictions as far as folders but keep in mind any blade carried will have to conform or blend into the uniform worn. During underway operations that won't be much of an issue. Especially during boarding's and LE operations.
Best of luck to your friend, congratulations on his graduating the academy, and thank him for his service!
I wish him all the best in the start of his new career.
